For the small 0.5 acre pond a 1/4hp unit is very adequate providing plenty of cfm for mixing the two basins and the underwater ridge. In my experience on the reduced scale, one 9" disk diffuser in each basin would adequately mix each basin. The ridge will mix naturally down to about 5ft deep in your area. Beyond that depth a little bubbling from a shallow center diffuser will help blend the two basins. Shipping a unit to you from the US will be costly, you should be able to find a source in Canada.
Last edited by Bill Cody; 06/18/12 01:29 PM.
