My old pond

Here you can see a picture of my old pond. it was 3500 liters and i kept 10 koi in there. I had a 3 chamber RVS filter with 10 black night brushes in the first chamber, PPC mats in the second chamber and in the thirth chamber springflo. The filter had two drains in the first two chambers which were operated by 1 vaulve and once a year i cleaned out the rest of the debris and cleaned the mats a little bit. I had three airballs in the filter to add oxygen to the filter for the bacteria and a 11 watt UV clarefier made sure my water was always crystal clear.  It worked great but because of the fact that the koi were growing very fast and i had to adjust my pond to make it a bit safer for the kids i made a new bigger one.

As you can see this pond was getting to small for the koi. In the winter i always placed a tent over the pond to prevent that the temperature dropped to fast which would cause problems for the fish. Although the watertemperature was sometimes very low i never experienced problems.