Union internal diameters, plumbing advise needed

[oaksenov]

I am thingking about all the plumbing options for my 175G and while I was collecting plumbing supplies and comparing them to what I already have it struck me that on those regular unions that we buy in Home Depot or anywhere else if it matters the smallest internal diameter is actually smaller than internal diameter of the pipe.

But for example on my Deltec AP702 skimmer water supply connector is with some metric 32mm union that actually sits on 1" pipe and matches internal opening it perfectly.

So I think although it wound be really nice to use unions that do not reduce the opening, it is really hard to find those metric unions here in US.

Now I am thinking is there a way to use US standard unions, but maybe keep internal diameters at least no less than a pipe diameter? Will oversizing unions and connecting them via bushings work? For instance 1" pipe to 1"-1.5" bushing to 1.5" union.

BTW where can find the specs like internal diameters for those unions?

Here is the opening I am talking about:

[reefermad619]

You can downsize pipe with the bushings. The only thing I would be concerned about is where the pipes will be. Behind the tank close to a wall or someplace where a big 1.5" union will take up alot of space. What kind of drain will you be using? If using a siphon, I would bother with upsizing. If using an air/water mix, like a durso or glass-holes kit, I would probably do it.

[oaksenov]

It is standard 175G bowfront Oceanic tank with bottom drilled with two Megaflow overflows, each has two holes for 1" and 3/4" bulkheds. Megaflows come with their version of durso pipe. I was going to give it a try. But bulkheads are already kind of small for 175G IMO. So I do not really want to slow them down even more.
The pipes are all going to be in the stand. I just have to figure out how to fit it all in there along with gravity fed skimmer, external pump etc.

[mcgyvr]

Just file/sand/drill the openings in the unions to be the same size.. Its only little smaller than the pipes ID if any at all. As long as you don't come close to the oring its not a problem.

[reefermad619]

And use the thin walled PVC. I think it's schedule 20? I know on the durso website they say to use the thin walled stuff to get as much flow as possible. If you have four 1" drains with proper sized pipe in the overflow, 1.25", they should each handle ~600gal. I would get a dremmel and bore out the unions or someother tool you might have access too. If you have to buy a tool, then downsizing the next size up union will be cheaper Vs boring out the correct size union. Are you going to be using any valves on your drains? You'll have the same problems as with tue unions.

[oaksenov]

Yes I think I need some ball valves in case I'll want to shut it off for maintenance. I see that US Plastic has some QIC2 valves that are advertized as "maximum flow".
http://www.usplastic.com/catalog/files/19248specsheet08-2002.pdf
So at least with vavles there are options.

I think I am going to try to dremmel it

[RokleM]

I can't confirm any of our sponsors, but the ones I purchase locally at Savko (http://savko.com/) are sized correctly internally without additional restriction.

[oaksenov]

Hmm. Were those unions from Savko schedule 40 or 80? I have 1" grey sch. 80 from Savko and one sch. 80 from home depot. They are both smaller than let's say the one on skimmer inlet.

[julie180]

Having dealt with ball valves, I would suggest going with gate valves. The ball valves can be tough to work and a huge pain in a confined space.

Also I'm curious, are you planning on unions on your overflow side? If so, why? I just saw a pic this morning where a guy glued unions right under the bulkheads????? From my perspective, that makes taking the bulkheads out of the tank impossible with out cutting the pipe. And, he did not leave any pipe to cut and reglue if it should be needed.

JMHO, correct me if I am wrong.

[Liquid Hobby]

If I were to do it again, I'd use only true union valves. Pricey, but they take up less space and are far better than standard ball valves.

[oaksenov]

Yep I would not glue the union to the bulkhead.

I was thinking to plumb it this way: the bulkhead is threaded so:
bulkhead->thread to slip adapter->valve->union -> flex PVC pipe


Having dealt with ball valves, I would suggest going with gate valves. The ball valves can be tough to work and a huge pain in a confined space.

Also I'm curious, are you planning on unions on your overflow side? If so, why? I just saw a pic this morning where a guy glued unions right under the bulkheads????? From my perspective, that makes taking the bulkheads out of the tank impossible with out cutting the pipe. And, he did not leave any pipe to cut and reglue if it should be needed.

JMHO, correct me if I am wrong.

[reefermad619]

That's how it should be done. Valves before unions, so the drain can stay wet. Makes it easier to prime.

[oaksenov]

I think I have one more piece to the puzzle. I stopped by the Home Depot and picked up another 1" union.

Here are comparison shot for your enjoyment:

From the left: Gray sch. 80 1" union that has been laying around for about a year. I think I got it from Savko. In the middle is sch. 80 1" union that I got from Lowes last week. And on the right is 1" sch. 80 union that I got today from Home Depot.

http://farm5.static.flickr.com/4086/5009823509_d6a880df23_b.jpg (http://www.flickr.com/photos/koi8r/5009823509/)
1" Unions (http://www.flickr.com/photos/koi8r/5009823509/) by Oleg Aksenov (http://www.flickr.com/people/koi8r/), on Flickr

First two look to be the same and right one is quite different. Although they are all for 1" pipe.
Here is union from HD on top of gray union to see how internal diameters are different.

http://farm5.static.flickr.com/4146/5010425024_fb75f7099c_z.jpg (http://www.flickr.com/photos/koi8r/5010425024/)
1" union internal diameter difference (http://www.flickr.com/photos/koi8r/5010425024/) by Oleg Aksenov (http://www.flickr.com/people/koi8r/), on Flickr

[oaksenov]

I forgot to add. The union that I picked from HD today matches 1" perfectly.

[Pickupman66]

well, now im glad I got mine from HD. One thing I may want to suggest is to get the threaded unions and then the threaded to socket adapters. while a little more expensive, should you ever have to re-do your plumbing, the threaded union is re-useable with just a new threaded adapter, while a non threaded one if you cannot cut the pipe long enough, could be trash. as expensive as they are when you get bigger, it hurts to trash one. I just setup a tank with 2- 2" unions and 2 - 1 1/2' ones.

[RokleM]

Hmm. Were those unions from Savko schedule 40 or 80? I have 1" grey sch. 80 from Savko and one sch. 80 from home depot. They are both smaller than let's say the one on skimmer inlet.

I almost always use their white SC40.

Having dealt with ball valves, I would suggest going with gate valves. The ball valves can be tough to work and a huge pain in a confined space.


However gate valves take up a large amount of space perpendicular to the pipe itself. Not always an issue, but can be. Tough to work is relative. The big box stores (lowes / home depot / etc) cheap ball valves are absolute garbage in my opinion. I can't tell you how many I broke, seized, or almost broke plumbing trying to turn them when I started reefkeeping. The only way I would use one of those is if it was a last ditch effort AND I had the time to put some silicone grease on the ball itself prior to gluing. That can help with the issue, but it's not a perfect solution. Personally I use Savko's true union ball valves where I can (one or two sided). I haven't had any issues with these.

Plumbing is one of those things that many don't take into consideration cost wise when starting a tank. To do it right with higher quality parts is a shocker when you see the price tag, but I also know that 100% of the time when I NEED to close a valve or disconnect a union, it will work... and my dry floors and wife are happy with that ;)