Water Treatments

Dechlorinator for every refill, beneficial bacteria to start and restart your filter, KH buffer to stop pH crashing overnight, plus ammonia binders, barley clarifiers, sludge treatments and montmorillonite clay. Microbe-Lift, Aqua Meds, Kordon, PondMax, API and TetraPond.

Two habits worth building. Treat the water going in, every single time, because chlorine and chloramine kill the bacteria colony you spent two months growing. And test KH, not just pH: koi ponds consume carbonate hardness continuously, and when it runs out pH stops being anchored and swings hard overnight.

Four white pond treatment bottles with black caps and a graduated measuring cup on a stone ledge beside a koi pond, for dechlorinating, buffering and dosing pond water.

Worth knowing before you buy

Ground rules and answers from the ponds we run every day in San Jose.

Know your real gallons

Every number in this hobby is dosed or sized by volume. Measure once, write it on the filter housing in marker, and stop guessing. Most people overestimate by a third.

Dechlorinate every refill

Chlorine and chloramine kill the bacteria colony you spent two months growing, and damage gills on the way through. Treat the water going in, every single time.

Turn the UV off while you medicate

UV-C degrades most treatments, and activated carbon strips them out entirely. Bypass both for the duration of a course, then bring them back online.

Common questions

How much water should I change, and how often?＋

Around 10 percent a week is a good habit for a stocked koi pond, either in one go or trickled continuously. Water changes are how nitrate and dissolved organics actually leave the system, and they replace the carbonate hardness your pond consumes.

Always dechlorinate. If you are adding a large volume at once, match the temperature reasonably closely and treat the incoming water rather than dosing the pond afterwards.

My pH keeps crashing overnight. What is going on?＋

That is almost always low KH, or carbonate hardness. KH is the buffer that holds pH steady, and koi ponds consume it continuously through the nitrification process. When it runs down far enough, pH stops being anchored and swings hard between day and night, which is far more stressful for fish than a stable pH at the wrong number.

Test KH, not just pH. If it is low, buffer it. Chasing pH with pH-adjusting products while KH is on the floor makes the swings worse, not better.

I am not sure what I need. Can you just tell me?＋

Gladly, and this is genuinely the fastest route. Send us your pond volume, your depth, roughly how many koi you keep and how big they are, your plumbing size, and the height from the pond surface up to your filter return. That is everything we need to size a system properly.

We have been building and maintaining koi ponds from San Jose since 1998, and we run this gear on our own systems. We would rather talk you into the right pump than sell you the biggest one.

Have us size your systemFull pond guide & calculator