The importance of pond water changes

Water changes are simply the removal of some old pond water, and the replacement of that old water with new water. It sounds so simple but there are problems, nationwide. First, water can be chlorinated. Second, alot of people don't do water changes, at all. Thirdly, failure to do pond water changes allows the accumulation of background pollution such as phosphates and proteins which inhibit pond fish health and growth. Finally, water changes need to replenish trace elements and minerals in the water which koi fish need.

Chlorinated and chloraminated water is usually supplied to hobbyists "at the tap" from municipal water supplies. The water company adds these two chemicals to disinfect the water. Each day, municipal source-water is tested for eggs, spores, ova and cysts of various pathogens. If any are found, it may be that the municipal water authority will double or triple the chlorine or chloramine concentration. Spritzing the water into the koi pond slowly WILL dissipate a lot of chlorine, but will it dissipate all of it? Dechlorinate. By dechlorinating the water, you can be 100% sure the chlorine is gone and will not harm your koi and pond fish. When your municipal water supply uses Chloramine, you will be relieved to know that dechlorinator can still bind the harmful Chlorine. The remaining Ammonia should be no match for a cycled (properly functioning, well colonized) filtration system.

In speaking to people from across the country, I found that about forty percent of the hobby is not doing ANY pond water changes at all. This accounts for recurring illness among the  koi fish, slow growth, and poor color. This is the most common cause of the "seven inch, seven year old" Koi. A koi in good water with plenty of water changes should grow at least 3-4 inches per year. Hobbyists should be encouraged to follow a pond water change regimen as outlined in the chart below.

"Topping Off" the koi pond is not a water change. You should know this about water: The solids in water do NOT evaporate, nor do many of the chemicals in the pond water. This means that the nitrates, phosphates, a good bit of the carbon dioxide, all the salt, minerals, etc NEVER leave the  koi pond and accumulate over time. As the pond water level goes down by evaporation, you may notice that the koi fish perk up as you add water back. There is a transient increase in water quality after the addition of 'new" water but it's rapidly offset by the dissolution of the existing background pollution. So, "topping off" actually concentrates solids and organic chemicals in the water over time. Real water changes should be endeavored.

If you are performing the recommended water changes, you should have robust, hungry and healthy koi fish.pond fish may still become ill, of course, however it is much less common in well managed koi ponds with LOTS of FRESH Water. Fact is, if you wouldn't swim in your koi pond, your pond fish shouldn't be.