Quick Guidelines For Effective Water Quality Management
Water Quality is the most important aspect of fish keeping. Most beginners and many experienced hobbyists make the mistake of not managing the quality of water effectively. Poor Quality water introduces stress in the fish and creates the right environment toxins which can ultimately cause death. So, here are some Do's and Don'ts:
- Do not overfeed. Overfeeding is one of the most common mistakes and is one of the biggest causes of death. Only feed with enough food that the fish will happily consume within 5-10 minutes. Only feed twice a day. Do not feed your fish when the temperature falls below 50℉. Uneaten food will sink to the bottom of the pond and will rot. Rotting food is eventually broken down into ammonia which is poisonous to fish. Uneaten food should be removed from the pond by netting off or vacuuming the bottom of the tank. Overfeeding also causes excess excreta from the fish which in turn when broken down will cause harmful ammonia.
- Treating newly introduced tap water (at pond set up stage and at water changing stage) with a proprietary de-chlorinator and conditioner. Tap water that is made fit for human consumption is rich in chlorine. Chlorine agitates fish causing them to scratch or flick against hard/sharp surfaces. Flicking may cause damage to the fishes mucus membrane and scales, leading to infection.
- Plants will help to reduce the onset of ammonia by utilizing some of the fish excreta and uneaten foods as fertilizer.
- Regular pond and filter maintenance will help to maintain safe water. It is recommended that you clean filters every 4 weeks. Clean filter media with pond water (not tap water) and remove sludge from the bottom of the filter. Filter media should only be cleaned to a level where some of the filtered material remains on the filter media. Heavy cleaning will kill any helpful bacteria from the filter media rendering your filter biologically ineffective for a number of weeks. In effect it's like returning the filter back to its new state where it will take a number of weeks to mature.
- Increased oxygenation and filtration helps to maintain good water quality. Oxygen is required by the fish to breathe and a lack of oxygen will lead to stress and the onset of illness. Good mechanical and biological filtration is also required to help remove impurities from the water.
- Remove dead leaves or those that have been eaten away from the main stem of the plant to prevent them from rotting and polluting the water. Rotting plant material also increases ammonia levels in the water.
- Remove dead fish or other aquatic life such as freshwater mussels as soon as they are noticed. Dead fish will cause dangerous ammonia levels in the water as well as breeding infection.
- Regularly monitor ph levels, levels of hardness and ammonia and nitrate levels. Proprietary kits are available to test each element as appropriate.
How frequently do I have to add water to my pond?
This depends on the size of your pond. For instance, under a normal circumstance, the water level of a 6'x8'x3' pond may drop 1/4" to 1/2" inch every week because of evaporation. When there is a high wind situation, the speed of evaporation may be faster than you expect. Sometimes water can drop a couple of inches overnight. If this happens simply add more water to return the pond to the proper water level.
What is a skimmer basket for?
Skimmer baskets establish the water level, house the pump and plumbing, remove floating debris, serve as biological filters, and circulate oxygenated water back to the pond. They also protect the pump from clogging. The filter mats and debris nets are very easy to remove and service.
How often do I have to clean the skimmer basket?
The skimmer basket is designed for catching the debris from your pond and housing the pump. In the autumn season, if your pond is built around the trees, you may check out the skimmer basket at least twice a week. If leaves block the entrance of basket the pump may not have sufficient water to circulate. You may hear the pump sucking air or see air bubbles coming out from your bog filtration pond. This is an indication that you need to clean the skimmer basket immediately otherwise pump may get damaged and void the warranty.
Pea soup in my pond (Green algae)?
One of the most misunderstood happenings every year in the life of pond keepers is the spring PEA SOUP. While this can be scary it really isn't so bad.
The winter pond is very much like a refrigerator. It stores up all kinds of leftovers and organic material (leaves, fish droppings, etc). The food in the refrigerator doesn't rot too quickly, but when we pull its plug and leave the door open for the spring-clean out- WATCH OUT! All of the leftovers have had time to age and now they process into other forms - very rapidly. Much of the leftovers in the pond has converted from ammonia to nitrites to nitrates already and the rest is ready to convert very quickly. But these nitrates (nitrogen fertilizer) have had nowhere to go. The plants have been asleep in the winter chill and have not been able to convert them to plant stuff (plants eat the nitrogen through their roots and convert it into more plant cells to make the plant bigger. In other words, the plants take the fertilizer out of the water and purify the water. Remember, the plant may be "in" the water but the fertilizer itself is no longer in the water: it is in the plant, which is only surrounded by the water) When Mother Nature hits the pond with a good warm sunny day, the water warms up enough to allow algae to grow. After all, the pond is full of nitrogen fertilizer (algae food). So the algae starts growing geometrically - that is, for example, each day it might double in quantity as it eats, grows, and reproduces.
But, it is saving your pond. Remember all of that nitrate that had built up all winter? Well, the algae is there to balance the pond and get rid of that potentially deadly nitrate by converting it to safe algae. So, the smart pond keeper encourages the Pea Soup to grow as fast as it can, to convert all of winter's chemical buildup into little obnoxious plants just as fast as it can. Meanwhile, the pond keeper needs to start housekeeping and clean the pond of all of the larger items such as leaves, sticks, etc from the pond's bottom with a skimmer net. Then one day after a week or two the pond is clear as a bell. Now you, the pond keeper, have to act to do your part. The pond is clear only because the algae have converted all of the nitrates to algae. Then they rant out of food - no more nasty nitrates - and all of the algae died of starvation - all at the same time. The pond keeper now has to quickly take his/her siphon hose or vacuum and do a 20% water change OFF OF THE BOTTOM. What you have just accomplished is that you have chemically cleaned the pond water of all of the winter build up. You now have a pond with its normal stability, buffering, hardness, aging, etc., but with no nitrate.
In a week or two the weather will allow the regular pond plants to start growing and they will continue the job of removing the nitrate as it is produced. There will be no more pea soup in a balanced pond for the rest of the year.
Yuck! I have green string algae?
Green string algae is the biggest headache for pond keepers. It is caused by too much nutrients in the water. This algae is found most commonly during spring and summer. To eliminate this problem, the proper filtration of the water is important. Either biological or mechanical filtration is required to remove the highly fertilized water and reduce this algae problem.
How often do I have to feed the fish?
Generally speaking, you should not feed your fish more than twice per day, and not more than they can eat within five minutes each time. Excess uneaten food pollutes the pond and creates toxic ammonia. You should not feed at all when the water temperature is 50 degrees or below. Colder temperatures slow down the digestive system of fish making it difficult or impossible to digest most fish foods.
How important are fish in a water garden?
Fish are one of the components in balancing a successful water garden. Fish also add color and movement; they bring your pond alive. Fish help the ecological balance of water gardens by acting as pond gardeners. They trim excess foliage and eat algae, mosquito larvae, aphids, flies and other insects. Koi are the most popular pond fish. They are intelligent, hardy, responsive to humans and come in a beautiful array of colors.
How long do I leave the light on each day?
Plants want a definite daily light and dark cycle each day; 10-14 hours is fine; twelve hours is the duration on the equator, where many tropical plants are found. You should buy a timer to automatically turn the lights on and off for you, since the plants (and fish) prefer a regular cycle to an erratic one. If the plants need more light, you should not extend the light period, as that will only help the algae. Rather, install another fixture and increase the intensity of light.
Do I need to have my pump(s) running all the time?
Pumps give your pond water circulation. If they are the right size for your pond and are properly placed, they eliminate stagnant water and provide oxygen to your pond. If they are connected or pumped to a filter, you reduce the effectiveness of the filter if your pump is not on and may end up having unsightly water and elevated levels of ammonia providing you have fish. Please keep in mind that you need to have at least 1/2 the total gallons of your pond pumped every hour for good water circulation.
How often should I backwash my Ultima II filter?
Once a week with a normal amount of fish and plants, twice a week for a large amount of fish and plants. Please do not forget to rinse (1/2 to 1 minute) the filter after you backwash (1/2 to 1 minute). Important note for Ultima II filters:
- You must turn off the pump each time before you rotate the valve from one position to the next one.
- Valve has to be rotated clockwise only. Failure to do so, valve and filter can be damaged and warranty will be void.
Water pH & Water Hardness
What is pH and Hardness? pH refers to the acidity or alkalinity of water. Different fish have learnt to adapt to different pH levels, thus, it's important to know the requirements of your fish. Although many fish can adapt to a range of pH levels, fluctuations outside this range may well prove fatal. It is important therefore to remember that readings should be taken regularly from specimen water samples and adjusted as appropriate. Proprietary water treatments can be bought which will alter (buffer) pH levels. There is a direct relation between pH levels and the toxicity of ammonia. When pH levels are low, ammonia is less toxic.
The origin of your water determines its hardness. Water originating from rain absorbed through the likes of chalk, limestone and clay is hard. That absorbed through clay being of Permanent hardness, and that through chalk and limestone being of Temporary Hardness.
Water originating from rain absorbed through peat or other organic matter will be Soft. There is a link between Hardness and pH in that Hard water is either neutral (pH 7.0) or alkaline (above pH 7.0) and Soft water is acidic (below pH 7.0).
How does pH impact on fish?
A pH measurement will help us determine if our water is a proper place to put the fish. For our Koi ponds, the pH should normally be between 7.0 and 8.5, but it is probably acceptable to be anywhere between 5.5 and 9.0. Although most of the fish could tolerate a pH as low as 5.0, bio-converter bacteria are subject to damage. Long term conditions above 9.0, can cause kidney damage to the Koi. pH impacts fish in several ways:
- First, if the pH is too low, a condition within the fish called "Acidosis" results.
- Symptoms are anorexia, and then production of excess slime, isolation, and resting on the bottom, finally, streaking of the fins, and death will occur.
- If the pH is too high, the fish will produce excess slime, and will gasp at the surface. Losses can be major. "Alkalosis" is hard to reverse once it occurs.
- On the other hand, Acidosis is rapidly corrected once the pH is brought up to a suitable range. IMPORTANT: pH is an indicator that shows the toxicity of Ammonia.
- At higher pH values, ammonia is more toxic.
- Below pH 7.2 most Ammonia is ionized to "Ammonium" and is far less toxic. This has relevance if you are considering raising the pH in a system with accumulating ammonias Test kits are available that use drops, pills, or powders with a color chart to show various ranges of pH. A wide range pH test kit (Range 5.0 - 10.0) is considered as a requirement for all ponds. If higher accuracy is desired, one or more limited range test kits are nice to have for the ranges most often encountered. Battery operated, digital electronic pH meters are available that measure from 1-14 in 0.1 increments. Most of the inexpensive versions of these ($100 or less) provide readings that are both temperature and battery condition dependent. All require periodic calibration and the less expensive ones usually require calibration prior to each use. Since doing this calibration is more involved than making a chemical reading of the pH, an electronic pH meter is not considered appropriate for most pond keepers. Those who have difficulty distinguishing the small color differences of the chemical test color charts find them wonderful. pH is prone to "fall" in un-buffered systems, and can fall precipitously due to Oxygen consumption, accumulation of Carbon dioxide, decay of fish and other wastes, and the normal activity of nitrifying bacteria which reduce Ammonia to Nitrite.
"Crashes" from a normal pH all the way down to pH 5.5 can occur overnight. At 5.5 the filter bacteria that may have contributed to the crash will shut down, preventing the crash from dropping yet further.
In systems where the pH has been chemically stabilized by any of the commercial buffers, the pH crash phenomena is not commonly seen. You may already have noticed that the water pH even fluctuates during a day. For example, the reading is the lowest at the dawn but the highest in the afternoon. According to a study conducted by the University of Maine, the water pH will increase as the water temperature increases. However, the effects of photosynthesis on the plants life in the pond is far outweighed the effects of the water temperature. Plants give off more oxygen through photosynthesis than they give off carbon dioxide (CO2) through respiration. As oxygen increases and the carbon dioxide decreases, it results the water pH to go up.
Much more important than either the actual pH and alkalinity measurements, assuming they are both in the acceptable ranges, are CHANGES to them. A typical established pond will normally settle down into an equilibrium state with a pH of about one half unit above or below the pH of the tap water used for replenishment. Over time (months), all of the inhabitants (bacteria, plants, and the fish) become acclimated to their environmental conditions. Stress occurs in all of them if they must adjust to any changes. Rapid changes in pH can cause extreme stress to the fish similar to shock in humans. A sudden change of a half or more pH unit in an established pond is an indication that something happened and the cause should be determined. Slow, longer term, changes provide other indications. Increasing pH and/or alkalinity trends in a pond are normally caused by lime leaching out of concrete and to a lesser degree by concentration due to evaporation and decomposing organic matter. Decreasing pH and alkalinity tendencies are primarily due to bacterial action that release acidic compounds. Concrete ponds usually stabilize at a slightly higher pH value than ponds with liners.
Established ponds will normally maintain their equilibrium pH value if sludge and decaying organic material is routinely removed from the pond, mechanical filter, and biological converter. Scheduled water change outs (10% per week for a small pond, less for larger ponds) are also helpful. Monitoring the pH by recording weekly readings (before the water change outs) can provide an excellent indication of any developing problems. pH values do change somewhat during each 24 hours, depending upon the temperature, quantity of plants (algae and others), and the size of the pond, so try to take the measurements at about the same time of day. Alkalinity measurements can provide a warning that a pH problem may be imminent.
If the pH gets out of control, high or low, increase aeration and conduct daily water change outs to bring it back into range. Recheck after each water change out and again in 24 hours. At a pH of 6 or 9, do daily 10% to 25% water change outs. For a pH of 5 or 10, do 25% to 50% water change outs. At pH extremes approaching 4 or 11, remove any remaining fish. CAUTION: Be sure and check and treat for any Ammonia presence BEFORE attempting to raise pH through either chemical or water change out means. Only under EMERGENCY conditions should chemical means be used to adjust the pH in a pond. Attempting to lower the pH chemically can be particularly hazardous to you, the biologic converter, and the fish (not necessarily in that order).
Repeating for emphasis, the value of the pH measurement, within the acceptable limits, is of little importance. A change, whether sudden or a slow trend, to the pH of an established pond, indicates action may be required and is why periodic pH measurements are important. Further, if your pH is reasonably stable and anywhere between 7.0 and 8.5, not only is there no need to attempt to adjust it, you probably will do more harm than good by trying to change it.
Ammonia is toxic to fish. Exposure to ammonia results in an increase in mucus on the fish. The increased mucus may harbor bacteria and parasites which will cause infection. Gills may also become swollen and both will result in the reduced ability of the fish to absorb oxygen. Typical symptoms include:
- Increased mucus layer on fishes mucus membrane.
- Swollen gills.
- Fin rot.
- Flicking against hard surfaces.
- Gasping at the surface of the water.
- Inability of fish to maintain its balance in the water.
Ammonia is present in water as a result of the following:
- Excreta (overfeeding produces more excreta).
- Decaying, uneaten food.
- Decaying plant material.
- Dead and decaying livestock.
- Filters can become blocked by any of the above thus reducing their efficiency.
- Filters that are deprived of oxygen can cause ammonia to be returned to the aquarium.
Reduce Ammonia by the following:
- Reduce feeding.
- Reduce stocking levels if overstocked.
- Feed with a good quality food substance.
- Remove dead and decaying leaves and plants.
- Clean tank regularly (bi weekly recommended).
- Clean filters according to manufacturers instructions.
- Ion Exchange Filter Media such as Activated Carbon, Charcoal and Peat can remove ammonia.
- Partial water changes.
There are two different types of ammonia; Ammonium and Free Ammonia. Ammonium is relatively safe for fish, whereas Free Ammonia is extremely toxic. There is a direct connection to temperature, pH and Ammonia as follows:
- High Temperature & High pH = High levels of Free Ammonia.
- Low Temperature & Low pH = Low levels of Free Ammonia.
- Proprietary kits can be purchased to monitor levels of ammonia.
Nitrites in the water are caused by the breakdown of ammonia. High levels of nitrites are also toxic to fish. Those steps listed above to reduce ammonia should effectively reduce levels of nitrites. The most common sign of nitrite poisoning is the fish gasping at the waters surface. Proprietary kits can be purchased to measure nitrite levels.
Nitrates are the end product of the breakdown of ammonia. It would be more worrying if Nitrates were not present in the water as this would tend to suggest that the filter is not functioning correctly. High levels of nitrates aren't generally harmful to fish, but there are some very delicate species that will succumb to illness if exposed to high levels for a long period.
Levels of Nitrates can be reduced by changing water and increasing planting (which will absorb nitrates as fertilizer). Proprietary kits can be purchased to measure nitrate levels.
Surface area is all important to the oxygenation of the pond water. Aeration increases the surface area of water that comes into contact with the air.
In warm temperatures, the amount of oxygen that can be dissolved in water decreases. At the same time, fish are more active in warmer temperatures and thus their requirement of oxygen is greater. The complete opposite happens in cooler temperatures where the water can dissolve plenty of oxygen. Fish that are deprived of oxygen may cause suffocation. Symptoms include:
- Gasping at the water surface.
- Congregating near oxygen sources.
- Fish may stop eating.
Too much Carbon Dioxide (CO2) in the water can also lead to Oxygen Starvation. As a bi-product of photosynthesis and respiration, plants produce Carbon Dioxide at night. High levels of Carbon Dioxide can decrease pH levels, thus oxygenation is essential.
One way to increase oxygenation is through aeration from either a returned filter outlet, a waterfall, a fountain or an air pump. Water returned from a filter can agitate the waters surface thus increasing the surface area and in turn, the amount of oxygen the water can dissolve. Air pumps will also create oxygen rich water by introducing oxygen directly into the water along with the fact that submerged bubbles will increase the waters surface area. Many smaller bubbles provide a greater water surface area when they submerge compared to fewer, larger bubbles.
Chlorine & Chloramines
Chlorine (Cl) is a gas which is added to municipal water systems to control harmful bacteria. In the United States, if you don't have a water well on your property, you probably pay for chlorinated water. Test kits are rarely owned by the pond hobbyist because it's an "all or nothing" sort of thing..... If you use well water, you don't have chlorine. If you don't use well water, you do have chlorine and need to take care of it before (or while) adding water to your pond. Most city systems run a chlorine content of 0.5 to 3.0 ppm, but will sometimes "flush" the systems with higher concentrations. Check with your local water authority to find out if chlorine is present in your water.
Chlorine is very deadly to fish in even very small concentrations, less than 0.5ppm. If affects the fish's gills causing severe tissue damage. Larger fish usually die more quickly than smaller ones and at a lower ppm. Even minute quantities of chlorine can also severely damage the bacteria in your biofilter system. Often times, the disruption of the biofilter (and the resulting ammonia/nitrite spike) following the initial damage to the fish is what causes them to die 3 or 5 days after the chlorine event.
Because chlorine is a gas in solution in the water, it dissipates into the air with relative ease. Simply spraying the water from your hose through the air on it's way to the pond will allow about half of the chlorine present to dissipate into the air. Never stick the end of the hose into the water when adding chlorinated water to the pond.
De-chlorinator chemicals are used to bind the chlorine still in the water until it dissipates naturally. We recommend using a de-chlorinator added to the pond anytime you need to replenish more than 10% of the pond volume (in small ponds, 2-5% in large ones). Small additions of water to the pond need not be treated in most situations.
In a brand new pond just filled with chlorinated water, about 1/4 of the chlorine will dissipate each day. If left to sit for 5-7 days, there is no need to treat the water for chlorine.
Chloramines is a compound which contains chlorine and ammonia that is also used in some parts of the country to control bacteria in water systems. This compound also results when sodium hypo chlorite powder is added by the water department instead of chlorine gas as a water treatment method. Water companies like this compound because it remains in the solution for a LOT longer than plain chlorine.
To test for the presence of chloramines take a 5 gallon bucket of tap water and use a de-chlorinator as directed. Next, test the water for ammonia. If ammonia is present, you've got chloramines. There are several de-chlorinators on the market which will take care of both the chlorine and the ammonia. Alternatively, if you have an established biofilter, it will manage the left behind ammonia after using the less expensive plain de-chlorinator to treat the water.
Adding Fish To Your Pond (How many fish can I put in my new pond?)
Fish stocking density is affected by many different variables. Larger fish require a LOT more water than smaller fish. The number of plants in your pond, the type of filtration system, and the dissolved oxygen levels in your pond affect it. The waste handling capacity of your filter system and how much of what quality food is fed plays a big role.
In other words, that's a tough question to give a definitive answer to. Suffice it to say that it's likely to be a whole lot fewer fish than you initially planned on getting. Most small water gardens (under 500 gallon) should stick to goldfish and avoid the much larger koi. Remember that the little fish you buy will grow FAST in a pond environment, and if too numerous, they can outpace the capacity of the filter system and result in dead fish. Besides that, within a season or two you'll start seeing baby goldfish who will ALSO grow to full size.
In general, each adult goldfish needs at least 15-25 gallons of water and each adult koi needs 100-300 gallons or even more. Unless you plan on substantially increasing pond size and/or filtration systems, you should plan for the eventual growth of the fish and keep the numbers down. Work closely with your local pond dealer to make sure you don't overpopulate your pond. Having a few very healthy fish who grow to attain their full color and size potential should be desirable over a whole herd of stunted sickly fish.
Adding new fish to an Existing Pond Population
Great care should be taken when purchasing a new addition to the pond. While koi and goldfish are rugged and hardy creatures, they suffer tremendously from the stress of transport to a retail facility. They usually arrive at your dealer with their immune system suppressed from the strain of transport and can be harboring deadly disease and/or parasite problems. These are things that you DON'T want to have to deal with in your pond. In particular, avoid the big super-chain stores that occasionally get large batches of fish in for cheap prices. Take note of the above info on overcrowding and picture the poor transport-stressed fish crammed 30 to a 20 gallon tank just like the tropicals.......... then look closely for the ones that float or lay quite still on the gravel, they're dead, you know! Either buy fish from a reputable dealer who quarantines his newly arrived fish, OR, build yourself a quarantine facility and keep the new guys isolated for at least 3-4 weeks BEFORE adding them to your pond.
Some folks like to add fish of other species to their goldfish and koi ponds. Pleocostumus, or algae eater or sucker fish, are usually one of the first choices. This is usually not a good idea for several reasons. All of those other fish are tropical, and have different water temperature requirements than cold water koi and goldfish. A Pleco may do fine all summer, but it'll die if left in the pond over winter. Besides, the only "algae" they eat is the beneficial carpet algae that grows on the bottoms and sides of the pond.
Add Only a Few Fish At A Time
Don't add more than 1 to 3 fish to your pond at a time. Adding too many fish at once will produce more waste than the filter can convert. Allow about 10 days for the biofilter to increase it's capacity and absorb the increased waste in the pond before adding another 1 to 3 fish.
Barley Straw and Algae Control
What's the newest, most innovative and cost effective way of controlling the simpler forms of algae in a water gardening setting? Well, how about tossing a small bale of Barley Straw into the pond? Yep, we said "Barley Straw". Farmers in Scotland have used this method to control green floating algae in farm ponds for centuries (or so the story goes). Nobody knew how or why it worked, but the farmers would toss in a couple bales of their straw every spring. The United Kingdom's IACR-Center for Aquatic Plant Management (formerly the Aquatic Weeds Research Unit) has conducted extensive testing into the dosage regimen and method of action for Barley Straw's algaecidal reputation.
How Does it work?
When the Barley Straw is introduced into the pond, it soon begins to decay (decompose, rot). Though not fully proven, it is suspected that the rotting straw releases lignins into the water. In the presence of plenty of oxygen, the lignins are oxidized into humic acids and other humic substances. It is also known that when sunlight penetrates water containing humic substances and dissolved oxygen, very small amounts of hydrogen peroxide are produced. Very low levels of hydrogen peroxide are known to prevent algae cells from reproducing and inhibit the growth of existing algae cells.
Since the barley straw releases it's active ingredients while decaying slowly, there is a constant low dose supply of these algae inhibiting chemicals. The existing algae cells are not killed outright, but since they no longer grow and cannot reproduce, the algae bloom will be controlled or prevented. When Barley Straw is applied to a pond that is already pea soup green, it can take up to several months for all of the existing algae to die off and the water to become clear. If added in the early spring, or in a new pond start-up, Barley Straw can prevent the algae from ever becoming established.
What Types of Algae Does it Work On?
Barley Straw works VERY effectively to control the planktonic floating green algae that makes our water look like pea soup. Research indicates it can also be a valuable aid in controlling string algae. It is most effective against string algae if applied before the stuff ever develops. In our experience, it works wonders at keeping the water clear, but doesn't work nearly so well against string algae. But what the heck, you can't ask for everything, can you?
Barley Straw has absolutely no detectable effect on any higher order plant or animal life. In fact, some folks think their koi and goldfish are healthier because of improved water conditions and the presence of small invertebrates (read as fish food) in and around the straw bale.
Dosage. How much to use and how often to use it? The single most important factor in determining dose is the surface area of the pond to be treated. Depth does not appear to greatly affect dosage schedules. This sort of makes sense when we remember that the sunlight penetration into the first couple inches of water is where the conversion to peroxide occurs, and that the surface layers is where most of the algae is.
The Center for Aquatic Plant Management recommends that "still" bodies of waters require a minimum of 10 grams of straw per square meter of surface area. This minimum dose roughly translates into about 1/3 ounce of straw per square yard of surface area. Most commercial pond companies we've found offer 4 ounce bales. Use common sense in modifying the dosage. In water that is very heavily laden with algae, doses of 50-100 grams (roughly 2-4 ounces) per square meter may be required initially, then may be decreased once the algae is under control. Higher doses are also indicated in very muddy or turbid waters. In very large bodies of water, the straw bales should be dispersed evenly around the pond for better effect.
The rate of decomposition of the straw is very dependent on water temperatures and levels of dissolved oxygen. In colder water, the straw may take up to 6-8 weeks to become effective. Water temperatures over 75° allows for faster microbial activity and the straw becomes effective in about 1-2 weeks. While most folks can expect to get five or six months out of each bale of straw applied, we poor southern warm weather folks usually need to replace the decomposed bales every 3 months or so. The algaecidal activity continues until the straw is completely decomposed (read as "gone"), but to maintain continuous coverage you need to start a new bale before the old one disappears. We make sure there fresh bales of straw in all our ponds early in February to ensure they'll become active by the time the spring algae bloom tries to occur.
How and Where is it Applied?
There are two varying schools of thought as to how best to use Barley Straw. The initial researchers recommend that the straw be placed in loose bales or in net bags and positioned where there is strong movement of freshly oxygenated water.
In our experience, in smaller garden ponds that are 3 foot deep or less, it really doesn't matter how you apply it. Just chunk it in the pond. You can use bales, tied sheaves, scattered loose straw, or the neat little net bags. The straw can be put in most biofilters, floated in the pond, stuck up under the waterfall, or put in the middle of the pond weighted down with a rock. As long as the pond has good healthy water flow and adequate aeration, it really doesn't matter a lot how you use it. In dirt bottom farm ponds, it may make a difference, but not in most water gardening situations.
Can I Use Other Types of Straw?
Folks who are trying to use non-barley types of straw report varying degrees of success. Those with good results have used wheat and rice straw, but at significantly higher doses and with less dramatic results when compared to Barley Straw users. If Barley Straw is absolutely out your reach, try to find straw from wheat, linseed, oil seed rape, lavender stalks, or maize. It's likely that you'll have to use 5 times the dose or more and apply it more frequently, but it can work.
The Negative Side of the Reports
Some folks have reported that their ponds fill with small chunks of floating straw and that these clog the pump and/or filter. There was some straw escape from the first bundles we ordered too, though we didn't see it as a problem. To correct it, however, we sell our straw bales in a close knit (800 micron) net bag which holds the big stuff in. Some folks have also said they saw no difference in their pond at all after adding barley straw. In closer questioning, we've found most of them to fall into two groups, ones who had already clear ponds and those who applied too small of an amount for too little time to a pond already too far gone in algae due to "other" design or care elements.
Math & Conversions
For a square or rectangular pond volume in gallons:
(Length) x (Width) x (Depth) = cubic volume
If measured in inches divide by 231
If measured in feet multiply by 7.5
For a round pool in gallons:
(Radius) x (Radius) x 3.14 x depth in feet = cubic volume, convert as above.
Note: for most ponds, calculate the volume as if the pond had straight sides and a flat even floor. To compensate, we then multiply the volume by .75 to .85
Feet Head (of water) x 0.433 = PSI (pounds per square inch)
PSI (pounds per square inch) x 2.31 = Feet Head (of water)