hole diameter vs. bulkhead size vs. PVC diameter

[dow]

Let's say, just for grins, that I drill an 1 1/2" hole in a tank. What size bulkhead do I need for this hole, and what size PVC will it accomidate?

Next question... What if I make the hole 1 1/4"? What about 1 3/4"?

Thanks for your wisdom and knowledge, Oh wise hole cutter sages.

[::pete::]

Here (http://www.marinedepot.com/aquarium_plumbing_parts_fittings_2.asp#bh) is a list of bulkheads with hole size and plumbing.

[iwantacans]

ohhh nice link... i gotta bookmark that

[dow]

Thanks, Pete! Just what I'm looking for. By the way, I just ran across this website: Savko Plastic Pipe & Fittings, Inc. (http://www.savko.com/index.asp). I think that their prices may be better than marinedepot.com.

[MikeDeL]

Dang that stuff is cheap... Is that the same lock line they charge 6 bucks for a 6" section at Marine Depot?

[Tim Marvin]

Savko make top quality parts, and great prices. Check the hole sizes again though because every 1.5 inch bulkhead is not the same. Some require a smaller hole or larger depending on how heavy duty they are.

[captexas]

Tim is correct that sizes can vary, especially on the 1.5in. They also vary depending on whether you are using schedule 40 or 80 bulkheads. Customaquatic.com has a lot of plumbing supplies and at fairly good prices as well.

[dow]

Ok, another question. If you have a bulkhead that is 1 1/2", does that mean that the inside diameter is 1 1/2" or that it will accept 1 1/2" pvc?

[captexas]

An 1.5in. bulkhead means it will accept 1.5in. PVC and/or PVC fittings. There are different kinds of bulkheads for the same size as well, slip/slip, threaded/slip, and double threaded. All depends on what you want to connect to the bulkhead and whether you want it permantly glued in place or use threaded fittings so you can remove the connected piece if you need to.

[dow]

Thanks, cap. That's what I thought, but I figured that it was better to be safe than sorry. I'm thinking either 1 1/4 or 1 1/2 " for my two overflow lines. The tank is a 65 gallon, and I'll be installing a Calfo style overflow. What would you recommend?

[captexas]

I don't have any experience with the Calfo overflow, but saw the one Joshua did on the tank he had awhile back. He can probably give you some info on what he did and would have done differently. As far as drains go, I think bigger is always better, but for a 65gallon tank I would imagine that two 1 1/4in. would be plenty. It depends also on how many gph you want. I can't remember what those two sizes will allow, but I know a 1in. will give you about 600gph drain. Hope that helps, and check with Josh on his Calfo overflow experience.

[::pete::]

As Chris said, bigger is better and you can always down size after the bulkhead.

[dow]

Thanks, Cap. You reminded me that I had discussed this with Joshua several months ago. What I'm shooting for as far as flow is concerned is to allow for a maximum of 20X through the overflow, so that would be about 1300 GPH. I doubt that I'll hit anywhere near that, as I plan initially to make up the turnover with powerheads in the upper rear corners aimed toward the opposite front corners. Eventually, I'll try to put in a return manifold that will replace the powerheads.

[captexas]

Based on the tool they have on ReefCentral, I came up with a 1 1/4in. drain will handle about 900gph and a 1 1/2in. drain will handle about 1300gph. I would assume these are maximum measurements. So with two drains on your tank you should have your 1300gph covered.

That's good you talked to Josh, I seem to remember there was something he didn't like or wanted to change, but I can't remember! lol

[dow]

Well, I just went to reefcentral and used their overflow calculator. According to it, I need at least 1.49" diameter overflow to handle 1300gph. If I run two 1.25's, that'll give me a drain area of approx 2.45 sq. in., which is slightly more than the area of a 1.75" pipe. According to the calculator, a 1.75" pipe will handle a maximum of 1800 gph, so IF the calculator is right, 2 1.25" drains would give me enough with roughly 500 gph to spare.

BTW, for those interested, the reef central overflow-drain calculator is lokated here (http://www.reefcentral.com/calc/drain.php).

[dow]

OOPS. Looks like we were running the same numbers through the calculator at the same time.

Any idea how accurate that is?

[captexas]

I think it is fairly accurate, but I wouldn't bet my life or money on it! lol I know the numbers seem to match those to what manufactured overflows advertise.

[jlam]

Well it depends on how you run your pipes as to what flow you get as well. I have two 1 1/16th that I can get 1200 out of with out much problem. I had to force the 3/4 inch bulkheads in there and it was very tight. But if I had to do it all over again I would have drilled probably at least 2 inch holes. Guess it depends on how big your tank is and how much flow you want. I have a 100g tank with a mag12 which at 4 feet head only give me about 1000 gallons per hour and it does not have any problems with keeping up. Actually I had 2 of my nars. snails get into the pipe and clog up 1 side probably 80% and it still kept up with the flow. I got my bits from this place if you want to drill your own tank they are pretty cheap but the bit will only last about 4-5 holes depending on if you cool it when you drill and stuff.

http://www.khue.com/dept/tool/dbits.htm

Good luck..

Jason