Mag Drive Pumps

[Jobu]

I'm looking into getting a Mag Drive pump to put in the 30-gallon sump of the 80-gallon tank I recently purchased. I was planning on ordering it from Drs. Foster and Smith, here. I wasn't sure which model would be best though. From what I've read on these forums, for a reef tank you want a turnover rate of at least 10x per hour, so it seems like the Mag 950 would be sufficient (950 gph). On the other hand, I've also read that the pump loses a little bit of that power when pumping against gravity back up to the tank (it'll be a distance of roughly 4 feet that it'll have to push water up in my setup). So maybe the 1200 would be a better investment (at 1200 gph)? More flow isn't a bad thing from what I've read.

Which would you recommend for an 80-gallon - the 950 or the 1200? At the moment I'm thinking I'll just go ahead and get the 1200 to be on the safe side, and if it ends up being too much flow I can throw a ball valve on it to reduce flow. Any input is appreciated. Thanks!

 

[fishfreek]

Buy the pump that flows no more water at 4' head than your overflow will remove. With that said if your overflow is rated at 600GPH you do not want a pump that does more than 600GPH or you will run into serious issues unless you use a ball valve to throttle the pumps flow.

If you click on the More information button and then the Flow Chart link you will see the predected flow chart for the given size at the head height of 4'. Each horizonal line is 1'. So a mag 9.5 will flow about 800GPH at 4' head and a mag 7 will flow about 450GPH at 4' head. Its ok to flow less than the overflows max rating but you cant flow more than the overflows max rating.

 

[Reese]

All depends on the rate at which water is returning to your sump. You can only return water to the main as fast as it exits. I just purchased a mag 9.5 and did the ball valve thing. What you want to do is put a T in the line and then a ball valve off of the T and a tube/pipe back into your sump. That way you're not restricting flow (fighting the pump) but merely diverting a portion of the return water. My overflow is only rated for like 650 gph so I almost have to have the valve completely open or else I'd have a waterfall pouring out of my hood.

Mag Drives are great pumps BTW. Good luck...

 

[Jobu]

OK, that makes sense...you only wanna pump back in as much or less than what's getting drained. Thanks to both of you for saving me from making a huge mess! LOL

I'm not sure what my overflow is "rated" at, but it is a hole drilled into the bottom of the tank that accepts 1.5 inch diameter pipe (after bulkhead installation). I believe I read somewhere (possibly on these forums) that the general rule is 600 gph per 1" of pipe diameter. So would it be accurate to say that my overflow is rated in the neighborhood of 900 gph?

 

[Reefer Guy]

For a tank that size a Mag 9 will be more then enough I'd consider a mag. 7 if it where my tank.. Good luck

 

[zuzecawi]

I have a 20 gal sump/refugium under my 58 Oceanic reef ready, and I run a Mag 9.5 with no problems and no restrictions. The stock 1" overflow built into the tank handles it just fine, and with the baffles in my refugium, there's no problems of washing out the fuge quicker than I want it.

 

[Jobu]

Good deal. I think I'm gonna go with the 950 and just throttle it back if need be. Thanks for the help!