Our pond is 33′ x 18′. The depth is from 3′ – 4.5′. It has 2 Savio skimmers with 1 Savio UV light in each. 2 Savio pumps pushing about 3700 gallons per hour. There are 10 koi and about a dozen goldfish-also, there are a lot of mosquito fish(very helpful). My suggestion to anyone wanting to build their own Koi pond- make it as big as you can the first time!!!!!- this was my 4th time!!