Pump question

[Rjung1]

Can anybody tell me if I will get more flow from a Mak-4 than an Iwaki WMD 30RLXT? At 6 feet of head? I've read the Iwaki chart - it says max flow 19 gpm, or 960 gph at 4 foot head. The Mak-4 says max flow 1190 gph, and the graph on the box is in liters and meters - argghhh! Can someone just tell me the answer?

 

[Rjung1]

No one?? I can't believe it!! Opinions from anyone who has owned these pumps are most welcome.....

 

[Rjung1]

OK, by my calculations the MAK-4 pumps 1050 gph at 6 feet of head; the Iwaki pumps 900 gph at 6 feet of head. Does that sound right?

 

[reefland]

MAK4 is a very good circulation pump but suffers under back pressure. If you're going to use it under pressure I would recommend an Iwaki 55RLT instead.

 

[Rjung1]

Richard, excuse my ignorance, but what exactly is "back pressure?" I would be using the pump as a return from my sump back up into the tank. The return line goes up approximately 4 feet and then goes thru two PVC 90's to go over tank's upper edge.

 

[reefland]

Richard, excuse my ignorance, but what exactly is "back pressure?" I would be using the pump as a return from my sump back up into the tank. The return line goes up approximately 4 feet and then goes thru two PVC 90's to go over tank's upper edge.

You'll be fine with a MAK4 then. "Back Pressure" is when you try to squeeze water through some kind of obstruction like a beckett injector on a skimmer. Plenty of people still use MAK4's for pressure applications it is just so you are aware that its GPH drops off under pressure.