2 pumps on 1 bulkhead? Ok or no?

JonT · #1 08-16-2010, 01:11 PM

Quote:

Originally Posted by intarsiabox

Will likely get cavitation in your pumps but you may be able to throttle the discharge side down enough that it will work. If you get a gravelly sound out of your pump(s) when you turn them on just close the discharge valves off until it goes away and then see if you are still getting enough output for your needs.

This is the most likely result.

Is this a CL? Trying to figure out what your up to, and trying to do? I am sure that this may have been the easiest way, but this hobby is full of DIY'ers, and I am sure we can come up with Plan B-Z for you

amoreira · #2 08-16-2010, 01:48 PM

Cavitation is rarely a concern for small pump a used for aquariums. Also Putting pumps in parallel does not reduce the suction head requirements (NPSHR). So go for it.

Delphinus · #3 08-16-2010, 06:40 PM

One pump is a Reeflo Dart for sump return, the other would be a GenX/Mak4 (assuming it still works, it should, it's just been shelved a few years), which would drive the skimmer (beckett). The GenX should be better able to push against head pressure and wouldn't be throttled; the Dart will likely be throttled but I'm not sure how much will be needed until I fill the tank and see how things settle out.

The Dart has a 2" inlet port and the bulkhead is 2". The GenX on the other hand has a 3/4" inlet port.

My worry is that one pump's suction could be perceived by the other pump much the same as a blockage or throttling on the input side. I know that throttling the outlet side of a pump is copesetic (it's just head pressure); but that throttling the inlet side of a pump is a no-no

so was sort of curious if two pumps pulling out the same pipe could produce a similar effect, or if it just creates a wicked suction into said pipe via the bulkhead...

Thanks for the thoughts..

StirCrazy · #4 08-16-2010, 10:47 PM

I would say try it but I doubt it will work good, but it could.

hows that for an answer

my concern is the size of the inlett of the dart. at 2" it will suck a lot of water but it all depends on the suction head pressure. if there is enough to supply the dart with lots left over then ya it will work, if not you will get cavatation in one of the pumps. best way to do it would be to have a large bulkhead, say 3" and have it go into a 3" pipe with a "T" on the end to feed the pumps. this will allow more water lower and creat a resivoir which is feed by a large bulkhead under a higher suction head.

Steve

Delphinus · #5 08-16-2010, 11:15 PM

Sounds good, thanks. It seems to me "it could probably work" also means "it could probably not work" and if there's a chance I have to drill out a new bulkhead anyhow, I might as well do it now when the tank is empty rather than down the road. I suppose that leaves more options open anyhow. Worst case scenario I end up not needing the bulkhead (ie., move to an insump skimmer) but then I can just cap it off, or use it for water changes or something.

golf nut · #6 08-16-2010, 11:20 PM

Darts can be fed with 1 1/2 bulkheads on closed loops easily because of the head pressure available, drawing from a sump however is slightly different, the higher the sump level and the greater the surface area will help in making this work fine.

I would go for it.

StirCrazy · #7 08-17-2010, 02:12 PM

Quote:

Originally Posted by golf nut

Darts can be fed with 1 1/2 bulkheads on closed loops easily because of the head pressure available, drawing from a sump however is slightly different, the higher the sump level and the greater the surface area will help in making this work fine.

I would go for it.

the surface area really has nothing to do with the pressure of the water at the suction, it is all hight. that is my concern as most sumps are not that tall and we don't run them full so the suction head is going to be small. now if he had a 24" tall sump and ran it at 23" I would say most likely it would work, but that is unlikely.

Steve

StirCrazy · #8 08-17-2010, 02:09 PM

Quote:

Originally Posted by Delphinus

I might as well do it now when the tank is empty rather than down the road. I suppose that leaves more options open anyhow. Worst case scenario I end up not needing the bulkhead (ie., move to an insump skimmer) but then I can just cap it off, or use it for water changes or something.

thats what I would do. makes for a nicer install also as you can have the pumps in different areas with out them being tied togeather.

Steve