How much water should you change each month?

There is a lot of discussion on this topic. First, we suggest that you consider what you hope to accomplish with your water changes. Andrew with Andrews Koi in Anaheim, California, has been conducting a koi growing contest with his customers each year for over ten years now. His primary reason for water changes when he began was to see how large they could grow koi in a single season. Andrew started ten years ago, recommending changing 10% each week. After examining the growing contest results every year, he now favors a 10% water change each day.

At Sacramento Koi, we tried something a little different. Rather than just growing large koi, we were more concerned with a regular water change’s primary health benefits. We set up a drip system in half our tanks that automatically exchanged 10% of the water each week. In our other tanks, we didn’t perform any water changes other than the filters’ regular backwashing. We conducted this test for one year. While the koi in the tanks receiving a 10% water change did indeed grow faster, the most significant benefit we noticed was that the koi were much healthier. Additionally, the water looked noticeably clearer. 

What became apparent is that regular water changes are significant to not only the growth, but the health of the koi. You have to decide what you are hoping to accomplish with your koi. If you are looking to raise your koi and keep them healthy, you should consider performing at least a 10% to 20% water change each week if possible. If your goal is to raise your koi to their full potential, both in color and size, you might want to consider performing even more substantial water changes. There seems to be a direct correlation between koi health and growth, and how much water is changed each week.

How much should you change at one time?

Many individuals like to perform occasional large water changes, up to 70% at one time. The logic is that the more water you change at one time, the more of the old water you are replacing. When you change smaller amounts regularly, you end up changing out some of the new water you recently added along with the old water. Large water changes may be a more efficient way to replace the old pond water, but it can cause more stress to the koi than is necessary. Koi do not like significant changes to their environment, such as water temperature, ph, alkalinity, or salinity.

Changing smaller amounts of water on a more regular basis limits the stress on the koi. The new Advantage GROW System offers the best of both worlds. It allows you to perform routine water changes at a rate that will not stress the koi and, at the same time, enables you to perform these water changes without wasting a drop of water.