Why is my pond foaming
A healthy pond should be relatively bubble-free. If you have some bubbles forming on the surface of your pond, it is typically caused by a build-up of dissolved organic compounds. Several things can cause this build-up of organics in the pond.
The most common cause is overfeeding your koi. But what if that isn’t the case? The next step is to look at your filtration.
If it is early in the spring and the beneficial bacteria in your filter has not had a chance to recover from the cold winter water, that too can cause bubbles. Try cutting back on feeding for a while to see if the filter can catch up.
However, if it’s mid-summer and you’re still having issues, your filter may be too small to handle your current fish load. Consider either reducing the number of fish in your pond or moving up to a larger filter.
If suddenly over a one or two day period you get a lot of bubbles on your pond surface, it may be that your koi are spawning. Look carefully at the sides of the pond. If your koi have spawned, you will likely see hundreds, if not thousands of tiny eggs, about the size of the head of a pin, attached to the sides of the pond. If this is the case, you will need to check the pond’s water quality over the next two weeks carefully (See test kits for koi ponds).
When larger koi spawn, they release a considerable amount of organics into the pond and filter system. Most filters bacteria is not prepared to cope with this extra load. You may get a spike in the ammonia and nitrite levels. It is best to clean your filter as soon as possible to remove much of this organic load. If you are hoping to get some new koi from this spawn, you will more than likely have enough eggs in the pond to have some survivors. If you don’t clean your ﬁlter, your water quality may degrade to the point of endangering all of your koi.
Want clear water ALL the time? Your filter may not be up to the task! Consider upgrading your filter system. You may also need water treatments!