Max GPH through overflow?

Vauche · 01/31/2009, 12:36 PM

I need a little help. I have an AGA 90G with built in overflow and I need to know what the max GPH it can handle is so I can match a return pump to it. Current pump is a Mag 5 that is connected via 1/2" PVC that is underpowered for the overflow.

Also with a total water volume of about 140-150G what should my flow be?

As far as I can tell the bulkhead has a 3/4" barbed connection and the standpipe is 1" diameter.

I currently have PVC 1/2" return line (killing my flow currently) and I am willing to re-plumb with either PVC or flexhose of any diameter if it will help.

Any help is appreciated.

reefnetworth · 01/31/2009, 12:53 PM

the more GPH you pump into your tank, the more GPH it will drian through the overflow.
in a 90G display i would have a Mag-9 min. or a Mag-12 to make up for head loss.
that way you get at least 10X's turnover ratio which is the norm in a SW tank.

as far as plumbing, i would go with 1.0" hard line, flex will restrict the flow some. and use 45 degree fittings, 90 degrees will also reduce flow.

MotherFish · 01/31/2009, 02:10 PM

The average rule-of-thumb on drainlines is approx 600gph for each 1" bulkhead.

Your Mag5 is pushing about 250gph at a head height of 5'.
A Mag7 will push about 420gph at 5' and a Mag9.5 will push about 750gph at 5'.
You can see a maximum flow chart for different head heights here: http://img79.imageshack.us/my.php?image=magpr6.jpg

If you go with an oversized pump then remember to put a valve on the output side of the pump so you can restrict the flow to the proper level.
*Never restrict the intake of a pump, only the output.

As for the total turnover rate for your tank that depends on what you are going to be keeping.
Some corals and species like a low flow, others like a very high flow.
What are you planning to stock?

Vauche · 01/31/2009, 02:49 PM

Thanks for the info.

I have been looking at the Mag 9 and need to make sure that the bulkhead I have in the overflow can handle that amount of water.

Interesting though I was under the impression that flex hose restricted flow less than PVC.

kraze3 · 01/31/2009, 02:59 PM

It depends how you have the flex hose. If its just a drop with a small arch you 'll be fine. If its making alot of corners or is pinched or misshaped in any way thats where the restrictions come from.

Vauche · 01/31/2009, 03:06 PM

As for total tank turnover I understand that concept, with the SPS I currently have about 2600GPH.

I guess I was really asking is what is the recommended turnover between display and sump, i.e. with 150G total volume what is the ideal GPH running to the sump.

What I think I'm hearing is there isn't such a thing as too much flow between DT and sump all things considered go as big as your overflow can handle.

kraze3 · 01/31/2009, 03:14 PM

Well there is another theory or opinion. SOme believe that the tunrover should be whatever your skimmer can handle. And all flow should come from your PHs or closed loop. The theory is that by slowing down the flow, more of the water is getting skimmed/filtered before returning to the DT. There is a large thread somewhere on RC.
Otherwise though as long as your setup can handle it you can go as big as you want.

Vauche · 01/31/2009, 09:59 PM

I guess the first theory is the one I was working on from the beginning.

So a stupid question.

If I plumb 1" PVC to the current bulkhead, which has a 3/4" barbed end, to me it seems that I would loose the advantage of the 1" return line as flow would have to be restricted down the 3/4" pipe at this point. Correct or grossly wrong?
Therefore, I would need to change the bulkhead to fit 1" PVC or go with 3/4" return line?

It's the details on how to plumb the thing I don't get, lol, the concept I understand just fine.

Vauche · 02/01/2009, 12:29 AM

Was doing a little reading at WetWebMedia.com and they seem to state that 1- 1" bulkhead for a return can only handle 300GPH safely. If you go more GPH you encounter problems, the least of which is noise.

What is the general opinion on this here?

Stanley-Reefer · 02/01/2009, 07:47 AM

I run a Mag 9 in my 90 and 2 Koralia 3s. If you can Y-split the return into 2 pipes, one shooting towards the long end (after the overflow) and the other back to the short end, they will give you all the flow you need.

I only have 60 net gal of water with 150# LR, 100# sand, and a small sump.

In that 60 gallons, I have 15 fish and over 55 colonies of soft, leather, sps, and lps. It's enough flow to keep staghorns, echinatas, millies, pavoa, torts, tablers--I owe much of that to my Euroreef RS-135

MotherFish · 02/01/2009, 09:21 AM

Quote:

Originally posted by Vauche
Was doing a little reading at WetWebMedia.com and they seem to state that 1- 1" bulkhead for a return can only handle 300GPH safely. If you go more GPH you encounter problems, the least of which is noise.

What is the general opinion on this here?

I agree that it's always safer and more quiet to run well below the maximum flowrate, and it's always better to have more than one drain incase one gets restricted or blocked.

While I have run some commercial systems at near maximum capacity without problems (other than the loud intermittent sucking sounds), the main display tank in my living room runs at about 40% of drain capacity and it is near silent.

The maximum flowrates listed by the bulkhead mfg are the maximum rate of water that can pass through that size opening at a full siphon.
Looking at a few bulkhead and holesaw mfg sites it looks like a consensus of those rates are:

1/2" ---- 150gph
3/4" ---- 350gph
1" ------ 600gph
1 1/2" -- 1300gph
2" ------ 2500gph

Unfortunately looking back at your setup, with a single bulkhead w/ a 3/4" ID barbed fitting it looks like the mag5 was already putting out the proper amount of flow to keep it slightly above half-capacity of the drain.
Unless you are planning to add additional drains then maybe you should just increase your turnover rate with powerheads.

Vauche · 02/01/2009, 10:45 AM

Well you answered my question there Motherfish.

It looks like I may have mislead unintentionally though, my drain is 1" my return from sump to tank is currently the 1/2" pipe, with the 3/4" barb. (don't ask, not sure what I was thinking)

I've also read about turning both the overflow holes into drains and then just plumbing up the back of the tank for the return to the DT, this may be a way to go for me.

Wonderful, thanks for the help!! I appreciate it!

Sounds like an awesome tank Stanley. Thanks for the input, will see about a Y split. How far away from the pump would you put that Y-split? I mean if you Y split close to the pump it would seem that you would greatly increase head pressure on the pump with 2 long runs.

01/31/2009, 12:36 PM	#1
Vauche Registered Member Join Date: Apr 2008 Location: Michigan Posts: 340	Max GPH through overflow? I need a little help. I have an AGA 90G with built in overflow and I need to know what the max GPH it can handle is so I can match a return pump to it. Current pump is a Mag 5 that is connected via 1/2" PVC that is underpowered for the overflow. Also with a total water volume of about 140-150G what should my flow be? As far as I can tell the bulkhead has a 3/4" barbed connection and the standpipe is 1" diameter. I currently have PVC 1/2" return line (killing my flow currently) and I am willing to re-plumb with either PVC or flexhose of any diameter if it will help. Any help is appreciated.

01/31/2009, 12:53 PM	#2
reefnetworth Premium Member Join Date: Mar 2006 Location: U.S.A. Posts: 3,810	the more GPH you pump into your tank, the more GPH it will drian through the overflow. in a 90G display i would have a Mag-9 min. or a Mag-12 to make up for head loss. that way you get at least 10X's turnover ratio which is the norm in a SW tank. as far as plumbing, i would go with 1.0" hard line, flex will restrict the flow some. and use 45 degree fittings, 90 degrees will also reduce flow. __________________ GIVE A MAN A FISH, YOU FEED HIM FOR A DAY. TEACH A MAN TO FISH, HE FEEDS HIMSELF FOR LIFE. (NEVER, underestimate another man's greed) Current Tank Info: SPS dominated barebottom display with BB sump since 2005, most consistant parameters in 19+ years of reefkeeping.

01/31/2009, 02:10 PM	#3
MotherFish Registered Member Join Date: Jan 2009 Location: Florida Posts: 208	The average rule-of-thumb on drainlines is approx 600gph for each 1" bulkhead. Your Mag5 is pushing about 250gph at a head height of 5'. A Mag7 will push about 420gph at 5' and a Mag9.5 will push about 750gph at 5'. You can see a maximum flow chart for different head heights here: http://img79.imageshack.us/my.php?image=magpr6.jpg If you go with an oversized pump then remember to put a valve on the output side of the pump so you can restrict the flow to the proper level. *Never restrict the intake of a pump, only the output. As for the total turnover rate for your tank that depends on what you are going to be keeping. Some corals and species like a low flow, others like a very high flow. What are you planning to stock?

01/31/2009, 02:49 PM	#4
Vauche Registered Member Join Date: Apr 2008 Location: Michigan Posts: 340	Thanks for the info. I have been looking at the Mag 9 and need to make sure that the bulkhead I have in the overflow can handle that amount of water. Interesting though I was under the impression that flex hose restricted flow less than PVC.

01/31/2009, 02:59 PM	#5
kraze3 Registered Member Join Date: Jan 2006 Location: RI Posts: 2,373	It depends how you have the flex hose. If its just a drop with a small arch you 'll be fine. If its making alot of corners or is pinched or misshaped in any way thats where the restrictions come from.

01/31/2009, 03:06 PM	#6
Vauche Registered Member Join Date: Apr 2008 Location: Michigan Posts: 340	As for total tank turnover I understand that concept, with the SPS I currently have about 2600GPH. I guess I was really asking is what is the recommended turnover between display and sump, i.e. with 150G total volume what is the ideal GPH running to the sump. What I think I'm hearing is there isn't such a thing as too much flow between DT and sump all things considered go as big as your overflow can handle.

01/31/2009, 03:14 PM	#7
kraze3 Registered Member Join Date: Jan 2006 Location: RI Posts: 2,373	Well there is another theory or opinion. SOme believe that the tunrover should be whatever your skimmer can handle. And all flow should come from your PHs or closed loop. The theory is that by slowing down the flow, more of the water is getting skimmed/filtered before returning to the DT. There is a large thread somewhere on RC. Otherwise though as long as your setup can handle it you can go as big as you want.

01/31/2009, 09:59 PM	#8
Vauche Registered Member Join Date: Apr 2008 Location: Michigan Posts: 340	I guess the first theory is the one I was working on from the beginning. So a stupid question. If I plumb 1" PVC to the current bulkhead, which has a 3/4" barbed end, to me it seems that I would loose the advantage of the 1" return line as flow would have to be restricted down the 3/4" pipe at this point. Correct or grossly wrong? Therefore, I would need to change the bulkhead to fit 1" PVC or go with 3/4" return line? It's the details on how to plumb the thing I don't get, lol, the concept I understand just fine.

02/01/2009, 12:29 AM	#9
Vauche Registered Member Join Date: Apr 2008 Location: Michigan Posts: 340	Was doing a little reading at WetWebMedia.com and they seem to state that 1- 1" bulkhead for a return can only handle 300GPH safely. If you go more GPH you encounter problems, the least of which is noise. What is the general opinion on this here?

02/01/2009, 07:47 AM	#10
Stanley-Reefer Registered Member Join Date: Dec 2008 Location: Stanley, NC Posts: 1,933	I run a Mag 9 in my 90 and 2 Koralia 3s. If you can Y-split the return into 2 pipes, one shooting towards the long end (after the overflow) and the other back to the short end, they will give you all the flow you need. I only have 60 net gal of water with 150# LR, 100# sand, and a small sump. In that 60 gallons, I have 15 fish and over 55 colonies of soft, leather, sps, and lps. It's enough flow to keep staghorns, echinatas, millies, pavoa, torts, tablers--I owe much of that to my Euroreef RS-135

02/01/2009, 10:45 AM	#12
Vauche Registered Member Join Date: Apr 2008 Location: Michigan Posts: 340	Well you answered my question there Motherfish. It looks like I may have mislead unintentionally though, my drain is 1" my return from sump to tank is currently the 1/2" pipe, with the 3/4" barb. (don't ask, not sure what I was thinking) I've also read about turning both the overflow holes into drains and then just plumbing up the back of the tank for the return to the DT, this may be a way to go for me. Wonderful, thanks for the help!! I appreciate it! Sounds like an awesome tank Stanley. Thanks for the input, will see about a Y split. How far away from the pump would you put that Y-split? I mean if you Y split close to the pump it would seem that you would greatly increase head pressure on the pump with 2 long runs.