how many GPH for return pump - NEW question please read post #39

+1, you will want the 3.0 if that is the brand you go with.

 

Find the pump curve. Since shutoff head or 0 flow on that pump is only 6.5 feet I doubt it will do 5x or a little more the display tank volume at 4 or 5 feet of head.
Places like Premium Aquatics and Marine Depot have most all pump curves on the website for comparisons. As tgp4274 said, look for something close to 500 GPH at 4-5 feet of head so you have a little room to play with by adding the valve on the discharge side of the pump. Don't grossly oversize but I'll bet something like a Eheim 1260, Ocean Runner 2500, MaxiJet 3000 Utility, Sicce Synchra 3.0 or 3.5 or Water Blaster HY-3000 or Octopus OPT-3000 would get you where you need to be.

 

I'm using a mag 7 with a cpr cs90 siphon overflow in my 65g. Working well for me. Put in float sensors and check valves to avoid any disasters.

 

Please don't depend on check valves, they are a false sense of security at best and will fail, not if but when. There is absolutely no reason for check valves in a properly designed sump system, none at all. As long as you can provide an air gap and your sump has sufficinet freeboard to contain a couple extra gallons a flood is not an issue at all, it will not happen.

 

Oh it has an air gap and won't overflow without the check valve. I just like redundancy. It won't overflow if the siphon fails or gets totally clogged, but I use float switches just in case. Never know what will happen.

I should add that for mag 7 flow at 3' head is 500gph, 4' 480 gph. I wanted about the same as you, 500 gph so the mag 7 looked good and is working well. It is a bit loud though.

 

Mag pumps are louder than many more modern and efficient pumps, they also use more power and run hot. The one good thing they have going for them is they are reliable, the same design has been in use for decades with no changes.

 

The mag 7 is also under $70 and draws less power than the Eheim 1260. Not that it's a better pump, but it still has a few things going for it.

Though it would be nice to have something with rubber feet on it. I cut and glued tubing on the mag 7 so it wouldn't vibrate on the sump bottom.

 

Mags don't draw less power than comparabe Eheims. Eheim is very conservative in their published figures, you will find they pump more than advertised and draw lower wattage than advertised. Mag on the other hand, in the tests I ran using a Kill A Watt meter, pressure gauge, 1" flow meter and valving drew more than advertised and did not reach some of the points on the curve they publish. I think this is common with many pumps on the market. You get what you pay for. If noise, heat and power consumption 24/7/365 are not an issue buy an inexpensive pump but if you are conservation minded and want a true value then look at better, more modern pumps.

 

Ok, you win! I submit.

 

Thank you all for the advice! I really appreciate it.