threaded bulkhead question
 

ok it's been awhile since ive had to replum the tank. i have two threaded bulkheads in the bottom of my tank, i can't for the life of me remember if i put silicone glue on the insert pipe threads before i screwed them in. what the hell did i do 3 years ago :eek: does it even make sence gluing them in? or maybe teflon tape? or nothing... ack!

I would put at least teflon tape. It would suck if there was a slow leak between the standpipe and the bulkhead that would cause your overflow box to drain into your sump in a power outage. Its not too bad if your overflow box is small or your sump is overly large, but if you have a lot of water in your overflow box (like me), then it could cause some problems.

i dont have a standpipe, the overflow goes strait into the sump. when i have a power outage or i shut the return pump off i have all the water hit the sunp. the sump used to be big enough to handle it.. heh lets hope the new one can as well.

the pipes in question are the pipes that screw in thru the bottom of the bulkheads that i hook my flex hoses into for the dump and return lines for the sump.

Oh, I see. Then definately yet. You'd hate to open the stand and find a pool of water on the bottom of it.

Teflon tape would work fairly well, but I usually silicone all the way around the bulkhead (on either the inside or outside.. doesn't really matter if the seal is completed) before I let 'er rip. With a good bit of tightening it's basically watertight, but it's also very easy for a small leak to still persist, and screwing that bulkhead on really, really tight can also stress the glass (mind you, I'm thinking of my 10 gallon fuge, not a behemoth display).

Speaking of bulkheads etc. I'm looking at getting my 75Gal drilled for it overflow. What size would you recommend. 1" 1 1/2" 2"?

Depends on how much flow you're going to be putting through them.

-Rich

Are you going to supplement the flow with other items such as powerheads or closed loops or is the return the only thing moving water in your tank? I personally would go with a larger bulkhead just so I can upgrade my pump in the future without any worry.

I agree with newguy. Better to have an embarrassingly oversize bulkhead fitting with a throttled back pump than an inadequate one that you're going to have to work around some time in the future. I believe reefcentral has a chart somewhere of flow rates vs. pipe diameter.

As alluded to by the others, it's better for an overflow to use larger diameter.

For a 75g, I would think 1-1/2" is adequate. 1" is certainly too small, don't even consider it. I would think 2" might be larger than you need (although you can always use bushings, etc. to step a pipe size down if you find 2" to be too bulky).

FWIW, my SPS tank is a 75g with 1-1/2". Sump return is a LG4, which yields me a decent sump turnover. For this size of tank, and the size of my sump, etc., I wouldn't really want much more flow from the sump (I subscribe to the school of thought that you don't need to overdo the sump turnover flowrate, but better to go with an "OK" sump turnover rate and then compensate for flow requirements with in-tank flow, powerheads, closed loops, etc.)