WHAT IS THE BEST WAY TO DETERMINE WHAT SIZE RETURN PUMP I NEED

[chumbucket]

I was thinking of running a mag 9.5 and teeing it off to run a return to each side figuring with elbows, tees, and head loss i would probably be down around 600 to 650 gph. Any thoughts would be appreciated

[brewercm]

That should be fine. I was running a Dart with two 1" bulkheads, granted a little dialed back but quite a bit more output than a Mag 9.5 probably between 3 and 4 times.

[azcummins]

I'd suggest getting a 900+ gph pump and on the return line(s), put a T- fitting that returns some flow back to the sump/refugium. If you put a ball valve off the T, then you can dial in how much flow you want going to your tank.

I have a 90g and I have an Eheim 1262. Plumbing the pump straight back to the tank caused a rip current that was too much for my tank. The T-fitting approach lets me dial in how much flow I want and it can be changed if needed.

[thedude]

We size our return pumps to circulate 4-5 times the tank volume through the sump, per hour. This slower flow allows your protein skimmer to work more efficiently, cuts down on salt creep, noise, bubbles, and the heat of a bigger return pump. With your tank at 65 gallons, I would have you shoot for flow 250gph - 350 gph.

If it were my tank, I'd take a look at the eheim 1250 (little to no heat, small size). If you are going to run your return into a chiller, or other flow restrictive devices, go up to the eheim 1260 but it is a larger pump and will put out more heat.

The flow in your tank should be entirely "in-tank" ie: closed loop, tunze's, vortech's, powerheads. Your return pump is simply to take water out of the tank, into your filtration, then back up into the tank.

John

[wkada]

I have a 65g with single 1.5inch overflow and dual 3/4 inch returns. I have a "tee" off of the main return with ball valve to feed my refugium which draws off quite a bit of flow. After doing the head loss calcs, etc., I ended up getting a Mag 12. If I run it wide open , its way too much! I'd recommend a Mag 7 or 9.5 max.

[R.Allard]

IMO and you have the space and funds go with a iwaki extenal

[mariog]

I have the same dimensions of tank but with one overflow. I am using a rio 2500+ and don't have any issues. I have used a mag7 with the same results, either of them work well for me. It's about 5' of head from the pump to return.

[R.Allard]

the external wont put as much heat in the water as a internal. big plus if your runnin halides or PCs. and you can T off to run other things. just depends on what you prefer