Anyone have experience with these? I'm going to be needing some pretty high flow for my river tank, and most of the powerheads either aren't strong enough or are prohibitively expensive. The Azoos are rated at a much higher gph than other pumps of the same price. Of course, I'm concerned with the quality of the pumps. With such a price gap, I'm hoping to find some people who have had experience, either good or bad, with them.