How many unions should I put in my system?

[glb]

I'm about to plumb my 40g build and here's my plan in order of flow:

Glass holes overflow box with bulkhead and 90degree elbow.

Pvc pipe to first 45 degree elbow. Union at elbow (do I need one on each side?)

Pvc pipe through back of stand to second elbow. Union after elbow. Some sort of shut off valve (probably not a ball valve but the kind with a faucet handle).

Pvc going into filter sock.

Sump

Pvc attached to return pump (with a union right there so I can remove pump to clean?

Pvc to 45 degree elbow that will go through back of stand. (Should I put a union here?)

Another 45 degree elbow so pvc is now vertical. A small piece of pvc between the two elbows.

Pvc up to the return, which has a 90 degree elbow connected to the bulkhead.

Glass holes return kit with lock line and a flare nozzle.

Does this sound like a good plan? Should I use slip joints or screw things together? Do I need more/less unions? Any and all advice is welcome. I want to do this right the first time!

 

[ReeferBob]

Put a union anywhere you think you might want to take things apart for maintenance. Definitely go with slip fittings. Don't forget valves where you might need to stop flow for whatever reason.

 

[glb]

Put a union anywhere you think you might want to take things apart for maintenance. Definitely go with slip fittings. Don't forget valves where you might need to stop flow for whatever reason.

Thanks. So would you put unions on each side of an elbow or valve? I need a check valve on the return side, right?

 

[AZDesertRat]

You will want to use a short piece of vinyl tubing right off the return pump to reduce sound transmission from vibrations and to allow for any slight misalignments in the plumbing. You will also want to place a valve on the discharge side of the pump to fine tune return flow unless the pumps is a DC controllable speed pump.
Place unions or true union ball valves so you can remove plumbing in sections small enough you can run a spring type brush through for cleaning. You don't need one at every fitting or valve, only enough so you can take a say 2 foot long section of plumbing out for maintenance or cleaning.
I always use threaded valves and important components so they can be easily unscrewed and replaced or modified in the future. I don't glue anything if it may need to be replaced down the road. I actually prefer a mixture of PVC and braided reinforced vinyl tubing so things can be moved around or adjusted or easily removed and cleaned or replaced. Glued up PVC looks nice but can be a real pain in the future if something starts leaking and rigid PVC can get very loud compared to tubing with little headloss of restrictions. Vinyl also takes stresses off of bulkheads. I have a Bulkhead Tips sticky thread on this site that has a lot of good plumbing information in it.

Check valves have no place in a reef system, they are a false sense of security and can and do fail. Keep the returns slightly under the surface so only a small, very easily calculated amount of backflow occurs before the return is exposed to atmosphere and the siphon breaks. As long as you maintain a couple gallons of spare room in the sump a flood will never happen. Most sumps operate best at say 1/2 to 2/3 full so that should not be an issue.

 

[ReeferBob]

+1 NO check valves. And you don't need all those unions. I've never taken apart my plumbing in two years. Just make sure you can isolate your tank if need be. So bulkhead, valve, then union coming out of the drain to the sump. From there anything you think might help.

 

[Volcmreefer]

Put unions adjacent to anything you will be performing maintenance on.

Happy Reefing!

 

[redfishbluefish]

I just did a union count on my 90 gallon DT with 40 gallon sump....with a 1500 gph Glass-Holes overflow.....a total of four. Here's what I got:

Three on the back of the tank....1 each for the drains, and 1 for the return:




One on the return pump so that I can easily take the pump out for maintenance (Old picture, but the middle section you can see the MAG pump and union above).




And with my two drains in the sump area, I simply did not glue the one connection....it's friction fit. It's been this way since 2008 and has never come off. It makes it easier to simply pull the pipe off when doing a sock change.

PIPE ON:


PIPE OFF:



The other pump I have (Cobalt 1200) is for the dual reactor and (I think) half inch tubing, that has a John Guest type quick-connect fitting on it.... so no need for a union.

 

[R_C]

+1 on the flex tubing coming of the return. I put a union on each return, one on each drain and a true union valve after my flex tubing just in case you have to do maintenance on your sump (pump failure, leaks, adjustments, etc).