Installing a bulkhead

[Sharkey18]

Ok, So I'm going to do it.

 

I have a Pan World pump which can pump up to 1750 gph.

 

So I am going to install a 1.5" bulkhead which permits 1300 gph, or a 2" bulkhead which permits 2500 gph. I don't want to have an input higher than what the pump can handle... or do I???

 

The pump has a 1" input so after the bulkhead I need to install a union with a valve and reduce to 1".

 

For a 1.5" bulkhead I drill a 2 3/8" hole.

For a 2" bulkhead I drill a 2 3/4" hole.

 

Anyone see any problems or have any suggestion?

 

Laura

[Brian Ward]

On the input side of a pump you want as much water as possible to be sure you never underrun the pump. A 1.5" would be fine, but I always go higher to minimize the suction forces in the tank. On the amount of water the pump is actually pumping will go through, so larger is always OK.

[Coral Hind]

If your pump is going to be close to the bulkhead then 1 1/2" is fine. If the pump is over six feet away then I would go with the 2".

 

Double check the actual bulkhead for the size of the bit needed. Some 2" only require a 2 3/4" while I have seen some that need 3 1/4".

[davelin315]

Two guys with excellent advice!

 

Only thing I have to add is that if you ever upgrade, you'll enjoy having the larger bulkhead already. Is this in a sump or off your main tank?

[Origami]

The other thing to consider, Laura, is that the larger the cross-section of the intake, the less off a vacuum-effect you're going to have at the intake(s). This can help keep fish and livestock safer from getting sucked up against strainers. Plus, if you feed the pump from multiple intakes that are tied together, you get a redundancy should any one intake become clogged.

[DaveS]

A quick note from the contrarian view- bigger intakes definitely are better for the the pump but may not be for other things. A 2" intake means a 2 3/4"-3 1/4" hole. For a glass sump, that would be a pretty big hole to drill and could bring you very close to the edges of the glass pane depending on pipe routing. Both of these factors will increase the possibility of cracking the tank when drilled. Also bigger pipes mean bigger (and more expensive) fittings. The expense may not be a concern but I seem to recall another thread about space in the stand for the sump and pump. In a sump, there's less of an issue with the vacuum sucking up the fish so you'll have to find the right balance of all these factors.

 

As Tom said, a couple of 1 1/4 intakes coming together on a T right at the pump input may be a better option than on bigger 1 1/2" or 2" hole. It does mean drilling two holes instead of one however.

 

Again, just more things to consider.

[Sharkey18]

The hole is going to be in the sump. The sump is a 40g and the pump is only going to be a few inches away from the bulkhead.

 

Any suggestions on where to buy the drill bit?

 

Laura

[Brian Ward]

The hole is going to be in the sump. The sump is a 40g and the pump is only going to be a few inches away from the bulkhead.

 

Any suggestions on where to buy the drill bit?

 

Laura

 

 

Since it's in the sump and the pump will be very close you won't gain much benefit from going to 2" - the pump only has a 1" inlet. I'm assuming the sump is glass? BRK and Aquarium One both stock bits for drilling glass, or you can order online - I found www.glassholes.com to be the best b/c they will ship via USPS so it arrives quickly and cheaply.

[Origami]

The hole is going to be in the sump.

 

Ahhhhh, I was under the impression you were putting in a closed loop. Looking back, there was no reason, one way or another, to think that, I guess.

 

Since it's likely to be a really short run, larger than 1-1/2" is probably not going to get you much. I wouldn't go as small as 1", though, as that will just add to the pump's work and may cause cavitation. Also, BRK normally stocks a lot of bits. Buy local if you can.

 

I assume that you've got overflow capacity that exceeds the pump's output (after head pressure considerations?).