Flow question

I just put a mag 9 on my 90 gallon tank as a return. I am running a 20 gallon fuge as filtration. I have the mag wide open and that is the fastest I have had on the return side. I made sure it would not overflow with a power outage and all is good. Do you think the mag 9 wide open is too much or should I just see how what goes on from here?

Thanks

 

it comes out to 47x/hr depending on the coral, yes as long as your overflow can handle it along with the sump.

 

I have a mag 9 on my 55 full throttle and is fine so you should have no problem with it, like reef-guru said, as long as the overflow can handle it.

 

Isn't a mag 9 turning 900 gph ? in a 90 tank that's turning 10 times per hour. Less your head pressure, so your not really getting 900/hour. But then again, if this is a reef you have displacement....

I am not sure about Reef Guru's calculation - but you would need to be pushing over 4,000 gallons per hour to turn 47/per hour. I like to always say that what works for one might not work for another, but turning a tank 47 times in an hour would be too much in my opinion.

Edit - forgot to answer your question ! No, I do not think a Mag 9 full open is too much - I think your just about spot on where you want to be.

 

It may be too much flow for your overflow. Is it a standard durso standpipe "reef ready"? I had a mag 9.5 on my tank and down graded because it was too much flow, and eheims were just a better choice for me in the end.

 

Well, seems the responses are kind of all over the place. The GPH is irrelevant here because we are not talking about that per se'. We are not talking about flow in the sense of "over all" flow. In simplest terms, relating to a tank with an overflow and sump, the return pump must accommodate the overflow rate. If the return pump is keeping a steady pace with the overflow rate as to not pump too much, too fast (causing flushing from the overflow trying to catch up) and not too slow, too little (causing the sump to over fill) then you have the correct return pump (flow).

 

I believe ReefGuru was referring to the turn over in the sump, as in this conversation, the turnover in the DT is irrelevant. Using the mag 9 should be fine. However, if you choose to add a refugium within your sump, that flow will most likely not allow adequate filtration of the water. It may also prevent the skimmer from functioning to its fullest. You may want to keep these things in mind.

 

The way I set my overflow is to max out the return pumps flow at first. If you get that loud and annoying flushing noise, back off the flow until the noise is gone. This is also minimize the amount of air bubbles that flow through the overflow's return line into your sump.

I currently have about 6x turnover through my sump, but my overflow and return does not effect the the turnover rate in the DT (which is around 30x) because the return line dumps into a seperate section of the overflow where my powerheads are for the DT..

 

The Mag 9 at a typical 5-6 feet of head(vertical distance plus a few fittings) pumps about 700 GPH. Thats pushing it for a 20G sump and may lead to microbubble problems due to velocity even with good baffles . You can always install a ball or gate valve on the discharge side of the pump and throttle it back for your conditions. Ball valves work fine, we are not talking rocket science here so getting the flow close is good enough. Valving the discharge will not hurt the pump in any way, in fact for most pumps it improves the performance by allowing you to find the pumps best efficiency point or sweet spot. It will also reduce the power consumption and heat generated by the pump slightly. By using the valve you can adjust it where ever you want it and alway open it fully if thats what works best.

Most people will tell you 3 to 5x the display tank volume is a good return flow but you also have to consider the size and configuration of the sump. If the sump is as big as the display, let it rip but if its relatively small then you need to use caution.

My display is a 100G and sump is a 30G long. the return is an Ocean Runner 3500 with almost identical specs as the Mag 9.5. At full open the 3500 is borderline, I get bubbles in the sump if I do not monitor the air intake on my Stockman standpipe and it can get noisy. If I valve it even slightly it quiets right down. My refugium is fed with a 1/2" line coming out of a tee on my overflow piping so I can regulate the flow so it is no problem.