External Overflow Box: Why All the Unions?

[Razorbacks]

I'm starting to design my plumbing for a new system which will have an external overflow box. I've noticed that a lot of people are putting unions or even true union ball valves within 6 inches or so underneath each drain bulkhead. However, I can't figure out why. What is the benefit?

I understand some people using a ball valve in lieu of a gate valve on the primary.

I also get that unions are nice to have from a disassembly perspective, but couldn't you just cut the lines later and add a union if you had to disassemble?

Am I missing something? Thanks!

 

[vandy]

If you ever need to take apart the tank, you can remove all the the plumbing for reinstallation without having to cut the pvc near the bulkhead to separate the stand from tank

 

[PharmrJohn]

Let's consider my future sump build as an example (40B with a 200g DT). I'll have removeable unions throughout my plumbing. I'll also have a ball valve (or some reasonable facsimile thereof) with each independent stretch of pipe. This way, if I want to redo my plumbing (adding, subtracting or rerouting), including total sump removal.via the side door, it'll be easy. No cutting and re-gluing. And ball valves give me full control on how much water I want to run through the set up. It's all about control and managing potential future changes seamlessly.

 

[Razorbacks]

Sure I get the disassembly angle, but don't see what's stopping someone from just adding the unions they need later (if they ever do).

 

[Chrisv.]

You WILL need to disassemble eventually, and you may need to do it in a semi hurry. It's way easier to cut and glue and all that jazz before the tank is full of water and can't be moved. PVC shavings from trimming are a pain in the butt in a tank.

 

[Razorbacks]

With PVC cutters it only takes seconds to cut a pipe and it's clean (no shavings). Re-assembly would obviously take longer. Agree with you there.

 

[Chrisv.]

With PVC cutters it only takes seconds to cut a pipe and it's clean (no shavings). Re-assembly would obviously take longer. Agree with you there.

Yeah I've been meaning to buy some of those.

 

[VintageReefer]

With PVC cutters it only takes seconds to cut a pipe and it's clean (no shavings). Re-assembly would obviously take longer. Agree with you there.

When tanks against a wall it could be hard to get cutters back there

 

[Sumbub]

Doing it now before you absolutely have to is basically saving for a rainy day. It's gonna happen. You might need to move the sump or maybe the sump popped a leak and you need to move it out. If you have the back placed against the wall, most people don't realize they should leave an extra 2-4 inches of space just in case they need to cut. Or maybe they don't have the space to do that and it's pressed against the wall. Prebuilding the union into the runs will be a lifesaver.

 

[Razorbacks]

100% the tank being up against a wall and thus hard to cut a line is true but a few things

1) Most people seem to be installing external overflows in the center of the tank. This makes reaching it even to loosen a union without draining the tank down pretty challenging or impossible on larger tanks. If you already had to drain the tank just to be able to access those unions, at that point you've already got great access to all your plumbing.
2) If you are changing out the sump you probably could make due with just one union further down the line in a more accessible location (right near the sump) vs 6 inches from the bulkheads.

 

[VintageReefer]

100% the tank being up against a wall and thus hard to cut a line is true but a few things

1) Most people seem to be installing external overflows in the center of the tank. This makes reaching it even to loosen a union without draining the tank down pretty challenging or impossible on larger tanks. If you already had to drain the tank just to be able to access those unions, at that point you've already got great access to all your plumbing.
2) If you are changing out the sump you probably could make due with just one union further down the line in a more accessible location (right near the sump) vs 6 inches from the bulkheads.

Well I can’t speak for everyone lol or why they do the things they do

 

[Razorbacks]

Well I can’t speak for everyone lol or why they do the things they do

Love it! I'm planning to install mine in the corner we as well for accessibility reasons.

 

[exnisstech]

Sure I get the disassembly angle, but don't see what's stopping someone from just adding the unions they need later (if they ever do).

Sure they could be added later but it's much easier to add them when building. I like to try and plan ahead and if I can do something to make working on things in the future easier I do it. No right or wrong just a preference. I don't understand why people obsess over pH lol

 

[Razorbacks]

Edit

 

[VintageReefer]

I don't understand why people obsess over pH lol

I’ve never gave a moments thought about ph in 23 years of keeping reefs.

I ordered fish online a few months ago and one died and for the doa policy the vendor asked me what my tanks ph was. I had to go buy a kit to find out lol. Used it once and never again

 

[Razorbacks]

Well I can’t speak for everyone lol or why they do the things they do

Out of curiosity what would you do if a drain bulkhead failed or was leaking and needed to be disassembled? Is the permanently bonded piece of the union small enough to pass through the hole in the external overflow box?

 

[exnisstech]

Out of curiosity what would you do if a drain bulkheads failed or was leaking and needed to be disassembled? Is the permanently bonded piece of the union small enough to pass through the hole in the external overflow box?

This is a manufactured tank so they probably used unions so the end user could assemble everything after purchasing

 

[VintageReefer]

Out of curiosity what would you do if a drain bulkhead failed or was leaking and needed to be disassembled? Is the permanently bonded piece of the union small enough to pass through the hole in the external overflow box?

The overflow box has an in tank and outside tank section

Remove the white unions so the plumbing is disconnected from the exterior overflow section

Remove the nuts from that bulkheads inside the overflow box

Remove overflow box and bulkheads. Replace gasket or do whatever repair is needed.

Reassemble

 

[Razorbacks]

The overflow box has an in tank and outside tank section

Remove the white unions so the plumbing is disconnected from the exterior overflow section

Remove the nuts from that bulkheads inside the overflow box

Remove overflow box and bulkheads. Replace gasket or do whatever repair is needed.

Reassemble

Yeah, you could take the entire box off to get room to work. I'm just curious if that permanent union end can fit through the overflow box when replacing a bulkhead/ gasket.

If not I'm guessing you would need buy an entire new union just to get the end piece?

This is one of my main concerns/hold ups with putting a union in during initial build. I'm worried the bulkhead is one of the most likely spots to fail/leak and I don't want to have to throw away an otherwise perfectly good union.

 

[VintageReefer]

If I had to replace either of these I would just take the lid off the overflow. There is an internal and external lid