Hi Cary,
I don't know the exact amount of water as I never gauged it. The Pond is 17 X 10 and 4 feet in the middle. I usually add water in the afternoon to cool the pond down or to make up for evaporation. Not only are there two above ground filters but there is also an in pond filter that goes through a sterilizer before dumping into the pond. The other two filter dump water back in via 1.5" PVC pipes about 6 to 8 inches above water surface. Actually my one concern is that there is a quiet place in the pond for fish to rest so that they are not always fighting a current. Oh, the pond guy in this area says to keep the sterilizer off for a month or two while the pond gets back to normal. Most of the fish seem to be loving it at this point. More water tests tonight.
Thanks for your reply!