I tried it last year with my Brookies in my ground sourced pond last year and couldn't keep the temperature under control even pumping in 5-8gpm of well water. I had ran the water thru a degasser system which also bumped up the oxygen level and actually decreased water temps but it was still no use unfortunately. I landed up buying a 500 gallon tank and moving them in doors and sure glad I did...I used less water and the growth was amazing!!! Search a few of my older posts and you will see my setup....going even bigger this season smile

Ryan