Hey docb,
RC51 here,
Yes you could use 2 of those fusers instead of 3 for your size pond. And I bet you could get by with the Eco 5 instead of the Eco 7 if you put your fusers somewhere in the middle around 7 to 8 feet. If you want it at the deepest end in 10 feet I would go with the Eco 7. I have the 7 and run it 8 hours a day and it cost me like 11 bucks for the month. So it's not to bad on the pocket book either if that's what your worried about. Hey good luck and let us know what you do.
