pond water quality

Experienced koi keepers are often heard to remark "We are keepers of water". Of course water is the environment we keep are fish in and it is dramatically differs from our terrestrial lifestyle

Without a regime of regular water changes and parameter testing, you will not be able to detect water quality issues in their early stages. This detection allows you to take preventative action and restore parameters to ideal conditions. When poor water quality parameters persist, parasite populations can explode, ulceration can develop and the fish can start dying off - and it can happen quickly

Water Test Kits and Meters

Buy a complete test kit which would include reagents to test pH, ammonia, nitrite, GH and KH. These are the most important parameters to test. Also deserving strong testing consideration are Salinity, ORP, Oxygen and Nitrate. Test kits derive results by mixing reagents with the pond water. Add the required number of drops as directed and compare colours with the provided colour chart. A salt meter is a highly recommended purchase and will pay dividends

With some tests such as GH [general hardness], a simple titration is performed to an end point [colour change]. It's important to realize reagents have a shelf life. pH is purported to last the longest at about 2 years, but readings from other reagents this old cannot be taken as accurate. Bottom line, purchase a fresh test kit every year - far cheaper than medications and replacing lost fish

ORP Meters

ORP meters [oxidation reduction potential] are also popular with the more serious enthusiasts as they provide an accurate snapshot of your water quality. The higher the reading, the greater the oxidation potential, the cleaner the water. Abundant organics, low dissolved oxygen and poor filtration will reflect a low ORP reading [<200 mv]. ORP meters are also very useful in the correct dosing of Potassium Permanganate, particularly for the 2nd. and 3rd. treatments when properly judging the water colour becomes difficult

Nitrification - The Key

Ammonia

NH3, is produced by predominantly by fish but decaying matter. It is toxic in even minute quantities [0.25mg/L] - damaging gills and skin, red blood cells [oxygen carrying] and increasing osmoregulation demands. It is far less toxic in cold water [2-3x] which is natures way of allowing fish to survive during the Winter when nitrifying bacteria do not function. As an ion, NH4+, it is not toxic. Because a higher pH has fewer H+ ions available, less NH3 is ionized into Ammonium and therefore there is more free ammonia. This explains why TAN [Total Ammonia Nitrogen] toxicity is a greater problem with higher pH levels

Nitrite

NO2-, nitrite can be a stubborn problem as it takes some time to cycle - 8 weeks or more. These bacteria require warmer temperatures [15 celsius+] and grow better in higher pH and lower salinity. They also require phosphorus to form ATP and fix Carbon Dioxide to obtain carbon. I have seen effective NO2- conversion at temperatures as low as 12 Celsius. Fish can absorb up to 30x the amount of nitrite that exists in the water into their bodies

Nitrate
NO3-, is far less toxic than NH3 and No2- as it is has minimal uptake by the fish. It is however, an immunosuppresentThese typically low level chronic conditions wear away at the fishes constitution by challenging the immune's system. The weakened fish is then more susceptible to more severe pathogens which can lead to a disease state and even sudden death. It also slows growth, promotes lethargy, jaundice and even blindness with extreme levels. Tap water in our area already has a reading of 12.5 mg/L nitrate. A level of 50 ppm is not ideal, but not of a great concern either

What Should you do when you have bad water quality ?

Maximize Aeration

Ammonia and Nitrite interfere with gills and the bloods ability to carry oxygen so maintaining a high saturation level is key

Add Salt

The increased ionic strength of a solution [water] helps turn ammonia into ammonium [non toxic] as well as limit the amount of NO2- getting into the blood stream. Levels of at least 0.12% are desired, 0.20% is a good target

Reduce Feeding

Feeding fish directly increases ammonia production. About 40% is barely digested and higher protein foods will increase NH3 levels. Feeding 1-2x per week can be a huge help in getting bad levels down and switch to a lower protein food

Ammonia Binders

We use CloramX and it instantly destroys ammonia. This is a great short term solution

Increase Filtration / Reduce Fish Load

Fish release ammonia constantly when breathing, and 60% of the ammonia present comes from gills. Increasing your filters capacity and / or reducing the fish load will have a immediate impact. Trickle towers & Rotating Media Filters are great, and a stocking rate of 1 lb. of fish / 100 gallons is reasonable with a adequately sized seeded filter

Water Changes

I find that water changes don't accomplish a whole lot in terms of actual impact on levels. I have done 100% water changes, only to find nitrite levels marginally improved retesting just 5 minutes later. Fish can actually store up to 30x the nitrite in their systems that is in the water and I surmise this is released back from the fish

Filter Bacteria Keys

Bicarbonates are essential for nitrification, along with 02. We already mentioned the importance of aeration, but maintaining adequate alkalinity levels is key. Using the tetra kit, you want to be at least 5 drops before a colour change. This equates of almost 90 degrees german hardness. Just add baking soda [sodium bicarbonate] for a quick boost in KH, but be mindful of the potential pH change. 1/2 cup per 1K gallons will increase pH 0.5 pt and KH at least 1 degree hardness [1-1.5 drops with the tetra kit]. Sodium Bicarbonate will ultimately buffer your pH to 8.4, whether it be 7 or 9

Managing Temperature
Being over 21 [70 Fahrenheit] is great for bacteria growth and the koi's immune system. Be careful however, because warmer water increases the toxicity of ammonia, as does a rise in pH. So there is a balancing act required, getting the water warm enough to encourage bacterial growth and conversion but to also manage the toxicity increase of NH3. Established systems with bioconvert down to 13 celsius even though nitrosomonas prefers warmer temps of at least 15

Bio Seeding for New Pond Syndrome

It is a normal process for a new pond to experience spikes in ammonia and then nitrite. It may take 8-10 weeks for the cycle to complete and decent WQ parameters to be recorded. It will take years for the system and media like kaldnes and japanese matting to fully mature

I do question the efficacy of bugs in a bottle. It seems to be very hit and miss and certainly not validated as clients do not employ the scientific method when dosing. The best results come from capturing the dirty water that results from squeezing out seeded filter media ie. sponge, from an established filter system. This brown water is then placed in your filter, with the filter turned off. Nitrifiers are sessile, so allow 20-30 mins. before turning your filter back on. I have observed good results with this method fast tracking the maturity of a new filter

We Perform Complete Water Testing at the Shop and on Service Calls

Water quality can go bad quickly, that is why we test our own tanks in the shop at least every 2 weeks. Remember, levels can be toxic and yet the fish will appear fine. When the fish show you there is a problem ie. clamped fins, lethargy, not eating etc. then the situation is advanced