That PH is probably model #PS-20 which pumps 160gph which adds about 5 to your total turnover rate. (gph
divided by total tank volume)
A good turnover rate on an average SW
reef tank to shoot for is between 25-30 when you add together all pumps, PH, filters, etc.
Personally I don't like the rotating powerheads (wavemakers) because the rotating part always seems to end up breaking on me, and sticking in a weird position long before the full life of the pump motor.
(I've got 4 of them and they're all stuck like that)
Less moving parts = less to go wrong in my book
, I would always go with a PH that's rated for bigger than the actual tank.
I figure over time all pumps gradually lose head pressure so it's better to start with an excess anyway.
You can always use a valve/nozzle to diffuse or decrease the output, but you really can't do anything to increase it. (unless you buy the type you can take apart and mod, but that's another topic.)
Also, if I remember correctly, (I don't have a box to check) the gph
rate that's printed on the box is normally what the pump will do at surface level.
If I'm not mistaken, I've seen some PH that come with a chart on their literature or box that shows less gph
the deeper underwater the PH is used.
Of course you don't want to get something so oversized that it turns your tank into a sandstorm, but the general concensus seems to be "bigger is better".