2 returns through 1 manifold?

[marduc]

Are there any potential problems, or any reasons why plumbing two return sources of water through the same manifold feeding my main tank would be unadviseable? One incoming stream will be ~250 gallons per hour, and the other will be ~450 gallons, since water will take the path of least resistance, would that not mean that both streams would converge, and simultaneously flow through the return nozzles of the manifold together, or would one inflow try to push upstream against the other backing up the one pump and creating a serious flood?

Would it be better to design two 1/2 manifolds, each servicing an individual return, or could I have both returns successfully plumbed through the same line?

[KRAZ4REEFS]

I have exactly what you are describing on my 90. I have 1 mag 12 and 1 mag 5, both are teed into the bottom of the manifold and then 3 outlets feed the tank. I get constant even flow through all of the outlets no matter if one or the other or both pumps are on, you will just get more flow out of all outlets. works great, good luck!

Scott

[hystrix]

I would advise doing two seperate lines. Possible problems running 2 different size pumps on the same return.
The higher flow pump may draw water from the lesser flow line (by a suction effect). The suction may disrupt the impeller of the smaller pump which may cause it to jam or the motor may overheat do to loss of head pressure. Most pumps are designed to run with some kind of resistance.

[KRAZ4REEFS]

Hate to disagree but I have had mine running with 2 different pumps for a year now and have the same 2 mag drives, no problems at all.

Scott

[hystrix]

are your pumps the same size? As I said it may cause a problem.
"The higher flow pump may draw water from the lesser flow line (by a suction effect). The suction may disrupt the impeller of the smaller pump which may cause it to jam or the motor may overheat do to loss of head pressure"
If the pumps are the same size then this shouldn't be a issue. unless one of them fails.

[KRAZ4REEFS]

As my first post says, I have one mag 5 and one mag 12 feeding the same manifold. They are not teed together but feed the manifold in different spots. Yes you are correct, if one pump fails, the pump that is still running will feed back to the sump, water goes the path of least restriction. I would reccomend putting in check valves between the sump and pumps, on each line from the sump to pump. Otherwise I don't see any problem with doing so, I don't see the suction effect theory at all, each pump is pushing water. If you teed the two pumps together to a single line maybe that would be the case.

Scott