What Size Holes for Bulkheads?

[pfritzbelly]

I am moving everything from my 3t-gal to a 75-gal and I have firmly decided that I DON"T want to deal with an overflow box any more.

So, I have decidfed to sack up and get some bits and try drilling the tank myself. The question is, what size of drains will I need? I will be return-pumping water from the sump via a Mag 12 and in a pinch a Mag Pondmaster 10.5. Will 2 1-inch drains be sufficient? I can look up the specs on the Mags if I need to supply them. Just wondered if anyone knew a quick way of calculating...

 

[glxtrix]

You could do 3/4 or 1" really. All depends on how much flow you want going thu your sump. And IMO, a MAG12 is a very large pump for this. A MAG7 or 9.5 would be more than enough. I run a MAG9.5 on my 140. I think my tank has 1" drain with 3"4 return....or maybe it's 2x3/4"????

 

[pfritzbelly]

Good to know. Come to think of it, it might be a 12 and a 9.5 that I have. I was going to use the 12 on my skimmer, but I was concerned about falling head pressure on the rise up to the tank. Maybe I'll use the extra flow to feed a larger distribution system inside the tank.

 

[etoh_is_good]

reefcentral has a bunch of calculators that you should use. head loss, drain/overflow size, etc. as for bulkhead, order the bulkheads first and then the drill bits. variation in bulkhead sizes will drive you nuts if you cut the wrong size hole.

etoh

 

[pfritzbelly]

Yet another very good point. I'll see what I can find at Aquabuys or somewhere nearby. Does Sal sell bulkheads?

 

[glxtrix]

I know he's has gotten some in the past. Call ahead to see if he has them for you.

 

[acroholic]

A standard 75 gallon reef ready tank from Oceanic, All Glass or Marineland has one 1" ID bulkhead hole for drain and one 3/4" ID bulkhead hole for return. Remember that the actual hole in the glass bottom is wider because the 1" drain refers to the ID of the bulkhead, not the hole in the glass. A schedule 40 1" ID bulkhead (most cases) needs a glass hole 1 3/4" in diameter. A schedule 80 (heavy duty) 1" ID bulkhead requires a 1 7/8" hole in the glass.

It is easy enough to buy the bulkhead you want and measure the OD of the fitting itself for your hole diameter.
Dave

 

[pfritzbelly]

Perfect. I think I have enough to go on. Hopefully, I can get the bulkheads this weekend and get the bits ordered.

I'll let everyone know how it goes.....