This is my frontosa pond, although I keep koi in it as well. The pond iteslf is 6,500 gallons with a square bottom, measuring 17 feet long by 10 feet wide by 6 feet deep. I built a bridge that crosses the pond right where it drops from the 2 foot shallow end to the deep end. It took me 6 months and countless hours with a jackhammer before I finally finished.
The problem was that 2 feet down I ran into slag (a byproduct of making steel). On the East Side of Chicago where I live, there used to be swamp, as it is very close to the lake. When they began building on the land here, they used this slag as backfill. Slag is like concrete, only a little softer but still hard enough for a garden hoe to not get through. So, I borrowed a jack hammer and a compressor from a buddy and jacked through it and dug, and dug, and dug ...
After digging out the crater like I wanted it, I laid the EPDM rubber liner and secured it with rocks along the perimeter, which were then cemented in place. Built into the side is a waterfall, two feet above the pond’s surface. This is used as the return from my filter, which pumps 5,000 gallons an hour. I have a UV sterilizer hooked up to the filter to keep algae to a minimum, keeping the water clear to bottom.
From late Spring to early Fall I raise most of my medium-large frontosa in this pond. I have to be careful they’re not too small or they’ll get sucked up into the filter. To accommodate the 5,000 gph load, the intake valve had to be quite “large.” They experience great growth while in the pond and when I pull them out, their color is just outstanding.
The koi stay in the pond all year. When the water is warmer, the koi stay near the shallow end. I feed them first, dropping in some koi food. They make a lot splashes snatching up every last piece of food, which attracts the fronts from the bottom of the deep end. They’ll swim up under the bridge to see what the fuss is all about with the obnoxious koi. From the bridge I can see the Blue Zaires hovering from just under the bridge all the way down to 6 feet. Then it’s their turn; I’ll drop them a small pile of sinking pellets and they’ll gobble it down. □