2 pumps on 1 bulkhead? Ok or no?

[Delphinus]

I have a bad feeling I won't like the answer to this, but I'm gonna pose the question anyhow in an effort to be optimistic.

Can I put a "T" on a bulkhead and run two pumps off the same bulkhead?

Or will the pumps "fight" each other too much for suction?

I really would prefer to avoid drilling for a second bulkhead, not that I don't mind drilling the glass but more out of space considerations, I don't really have a spot for a second bulkhead, short of patching over the existing hole and redrilling both holes. The whole idea just totally deflates my balloon. I'm tempted to try it and see what happens but the cost of 2" PVC bits (I've got a kick arse 2" true-union valve for blocking off the bulkhead side so I can do things like PumpMaintenance(tm) down the road, but the sucker is HUUUUUGE .. and .. um .. expensive. So I don't want to screw this up and have to buy a new one.)

[MitchM]

What pumps Tony?

Mitch

[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.

[golf nut]

Depends on the bulkhead size and the pump inlet size. what do you have?

[JonT]

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]

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]

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]

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]

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]

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.