The Aquaclear is the best HOB filter on the market as far as I'm concerned. The Tidal 75, I am not familiar with, but there is nothing wrong with running it at 50%. Matter of fact it may clean even more. I have the Fluval FX5's, and only because 1 was given to me, and the other was the closet you can get to be free. I am one of the biggest fans of Eheims classic line, and I think a 2217 would do very well on that tank. You would also have a longer cleaning interval.