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MAg 18 Enough or add TOO MANY PUMPS!!!!!!!!!!!

I have a 150g Starphire Oceanic Tank Dual Overflows on the back wall.

40LX30HX24W


CUrrently I have a MAG 18 pushing through a 3/4" Vinyl Hose into a T Splitter (soon to by a Y) and up into a standard Reef Read Returns and plit into 2 locline outlets at the top.

Mag 18 -> T Splitter -> 2 2.5' Section of Hose -> up 2 1/2" Returns -> Split at the return outlet.

Inside the tank I have 2 Tunze 6200's and I'm adding 2 more 6100's


I just purchased

2 NextReef MR1's
1 NextReef MR1 XL's


the 2 NetReef MR1's will run carbon and phosban respectively.
the XL I want to run biopellets.

If I built a Manifold would I be able to power all 3 reactors and still have adequate return? - ATM I'm thinking my return is too fast.... But I dunno.. I see people using a Eheim 1262 on a 180 Gallon Tank as a return.. so i'm like WTF... that pump is rated at like 900 GPH and mine is rated at 1800!!!!!
 

redfishbluefish

Officer Emeritus
Officer Emeritus
Head loss on MAGs are pretty high. I’m pretty sure RC has this choice in the Head Loss Calculator. I’m currently using a MAG 18 to drain a 55 gallon drum of RO/DI waste water. I pump the water up between four to seven feet (dependant on how full the barrel is) and it takes me about a half hour to empty the drum. Translation: A MAG 18 with ¾ pipe and 5/8 hose with about maximum seven foot of head runs at about 100 gallons per hour…..nowhere near 1800 gph.
 
I have an Oceanic RR 180, 72 x 24 x 24, similar config on the overflow/returns. I have two Mag 9.5's for returns running directly to the tank through 3/4" tubing(no fittings). With about a 4' head loss, I should be getting about 700 to 750 gph from each, so collectively about 1400 to 1500 gph. For additional circulation I have two Tunze 6085's that I run on timers 2hrs on/off. and two 6025's I use to provide flow behind and through my rock work, these run 24/7. I chose to install separate pumps on my reactors since the should have different flow rates through each, i.e. slower for GAC, faster for GFO, etc. and rather than dampen the flow using a valve I matched the flow requirements for each by using an appropriate sized pump, i.e. MJ 400 for GAC, MJ 600 for GFO, (using BRS reactors).
 
So my only choice is to add more pumps into my mix? I'm starting to re-think this mag return pump. I'll be dammed though if its never given me problems and is hella easy to maintain.
 
Fwiw, drop the vinyl and plumb up 1" right off the pump. You will probably double the flow you are currently getting. You probably can run 1 or 2 of the reactors then.
 

Fish Brain

Officer Emeritus
Officer Emeritus
If you are going to run bio pellets, it is not recomended to use phosban with them. You can starve the bacteria and not get the full benefit of the pellets. That will eliminate one reactor and less loss from your pump.
 
AqOb said:
Fwiw, drop the vinyl and plumb up 1" right off the pump. You will probably double the flow you are currently getting. You probably can run 1 or 2 of the reactors then.

You might want to go to a Mag 24 to do this, since it has 1" input and output, and the Mag 18 is restricted to 3/4" in/out.
 
downbeach said:
AqOb said:
Fwiw, drop the vinyl and plumb up 1" right off the pump. You will probably double the flow you are currently getting. You probably can run 1 or 2 of the reactors then.

You might want to go to a Mag 24 to do this, since it has 1" input and output, and the Mag 18 is restricted to 3/4" in/out.

There is little gain by upgrading to a 24. Approx 200gph.
 
Also, never restrict the intake ot outlet by going smaller, but to a point you can improve flow by going a bit larger. So fitting 1" to a 3/4" in/out on a pump is a great move and will improve performance to a point.

Increasing the pipe IN decreases the possibility of cavitation.

Increasing the pipe OUT decreases frictional loss reducing the total dynamic head the pump needs to overcome.

The Mag 18 is definitely on the RC Head Loss Calculator. This is a great tool when planning out your plumbing. Even if the pump you want is not on it, you can still accurately estimate the head loss with the calculator, then go to the pump curves for the pump.
 
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