Gal Waste

Gal Waste


Koi Pond Construction: Is a bottom drain really necessary, and is river rock ok on the bottom?

I've read a lot of info that says you need a bottom drain. I'm building about a 1500 gal koi pond. I have a savio skimmer and filter waterfall. Do I need to get a bottom drain also? I also read that gravel on the bottom is a bad deal because it leaves a place for waste to sit and rot. Is that true? I have some river rock I was going to put on the bottom. Is that ok or will I have problems later? Any help would be appreciated

You don't "have" to have a bottom drain, but they make maintenance much easier and, I think, contribute to better water quality and health of your fish. Plus, you can hide your pump easier that way, too.

I have had two 500-750 gallon ponds, and niether had a bottom drain. But, we were constantly cleaning muck out of the pump bucket and the submersible pumps were an eyesore. Also, you usually can't get submersible pumps with much head pressure to run a good-sized waterfall.

We now have a 3,000 gallon pond with a bottom drain and an externa pump, and it is SO much easier to clean. As waste drifts to the bottom of the pond (it is about 3 feet deep, below ground level, at its deepest), the solid waste material gets sucked into the drain and deposited in our 500 gallon veggie filter. The muck settles in the veggie filter where the water iris just thrive on it. Their roots scrub the water clean, where it then falls down our 8' waterfall and back into the pond. The pump is hidden in a cedar box on our nearby deck, that appears to be (and is used as) just a bench.

We clean the leaf basket out of the pump about every 2-3 weeks, squirt the filter pad of the skimmer and empty its leaf basket about once a month, and clean our veggie filter once a year, is all. And, we do virtually NO maintenance to the pond itself - the bottom drain and the skimmer and the filter do it all. We just add any water lost from evaporation. When enough muck builds up on the bottom of the pond, we'll drain it most of the way and clean it out, but that's once a year at the most, too. More like every other year.

As to your other question about river rock on the bottom of the pond, there seems to be two schools of thought on this issue. One is that the rocks do allow for a greater accumulation of muck and gasses, etc. The other is that its simply a greater surface area for beneficial bacteria to colonize and so is actually helpful.

My personal experience is that rock-bottomed ponds are MUCH more maintenance intensive - the muck really does accumulate and it has to be cleaned out more often than ponds with just liner in them, and believe me - THAT is a nasty job (one year I got contact dermatitis up to my elbows from getting in their and cleaning it out - it took months to go away!). I tend to think that whatever benefits you get out of the extra bacteria are more than cancelled out by the extra muck, the smell as the gasses escape, and the associated extra work in maintenance.

One other thing to consider: do you want a natural-appearing pond, or do you want to keep fish? The ponds I have seen locally with really big, fat, and happy koi, seem to be "liner only" ponds with rock coping and/or sides. The ones with rock bottoms may look more "natural," but the fish in them seem only to be "so-so." Fish will flash, i.e., rub themselves on the sides of the pond, etc., and rocks can scrape more scales and do more damage than will a plain EPDM liner.

Hope this helps. Feel free to e-mail me through my profile if you have any questions - good luck!