Let me try to understand. There is an annual clean up that required to empty the pond out and refill?
Yes. I don’t have a bottom drain. I have rocks and gravel. So, technically, the serious “koi people” would say that I don’t have a “koi pond”. They prefer deep ponds with vertical sides (like a swimming pool) with bare liners with bottom drains. And no rocks or plants. Very sterile. Their reasons are the bare bottom with bottom drains will remove fish waste as the water is pumped out to the filters. And, they use filtration systems that are more like a swimming pool. The water is returned back to the pond via a pipe, and is often just that, a pipe. The benefit of such a system is there is very little for a fish to hurt himself on. The deep sheer sides prevent Herons or raccoons from fishing. Fish waste doesn’t accumulate. The fish can be fed fish food that sinks to the bottom. Koi are natural bottom dwellers and their mouths are positioned to eat off the bottom. The drawbacks are they tend to hang out on the bottom, and you can’t see them well. The fish get bored since there’s nothing to do. With no plants or rocks, the view is rather stark.
What I have is a “water feature with koi”. Yes, it’s a pond. The filtration system is a “bog filter”. Water from the pond is pumped up above the waterfall, and down into the bottom of the bog. From there, it rises through layers of rock, eventually rising thru a bed of pea gravel and coming to the surface as if it were a spring. I’ve got plants planted in the pea gravel. The plants remove the nitrate so the water stays pure. The nitrogen cycle is handled perfectly in a natural way via this system. The only bad thing is the fish poop. It will settle on the bottom. Now, most of it breaks down by bacteria, but it does accumulate. So, once a year, we pump out the water (saving as much as we can) and pressure wash everything to get rid of the sludge. The plants stay in there. The dirty water is pumped out onto the lawn. Then the old water is returned to the pond, and I top up with fresh. Obviously, we add something to detox the chlorine.
My fish are happy, they get to nuzzle around in the gravel looking for what ever it is they hunt for. They like to nibble on the plants some. They like to hide in the nooks and crannies of the rocks, and they’re constantly sucking on them to eat the small amount of algae that grows on the rocks. Now, I will admit, occasionally, I’ll notice that one or another of them will ”bump their head” on a rock, and knock some skin off. It usually repairs itself in a couple of months. So, if I were trying to raise perfect koi for a show, this is not the kind of pond to have. But, I like the beauty of mine, and the fact that all the filtration is natural. I never have to add any chemicals to the water to adjust for “hardness” or anything. I do have to top it up every 3 or 4 days for evaporation if it hasn’t rained. Usually about 30 minutes of adding water does it. oh, I forgot, the fish have developed a taste for water lily flowers. They don’t eat the leaves, but they like the flowers. I think they do that to get me to feed them more!
