Hello, I'm doing a overflow/sump diy and for the DRAIN pvc pipes I'm doint the Herbie system where the flow is adjusted by the gate valve so that I don't get the gurgling sound. I know most people seem to use pvc glue but few ppl say for DRAIN pipes there isn't much water pressure so I don't need to glue them. Is it absolutely necessary to glue those pvc joints? BTW some parts are so tightly fit that it's almost impossible to dissemble them now.

Definitely use the glue. If you want to be able to take it apart plumb in some unions. You may get away with getting a dripless fit without glue, but there is still a chance of salt creep and leaks down the road.

I speak from experience. I had a herbie that salt creeped on threaded pvc with teflon tape. Couldn't get it to stop until I went with pipe dope. I realize that threaded is a bit different, but it was still a darn tight fight that leaked.

Oh, and those tight fitting pieces with slip together like butter with the glue. PVC fittings are not meant to be used without it... and do be careful of getting the dry fits stuck together. They can be a b#### to get apart once they're stuck.

Just use the glue until it is over your sump you will be VERY sorry if you don't, the stuff is cheap compared to 20 or more gallons of SW> all over the floor. Dry fits are not a good idea at any turn in the PVC.

If you don't want to glue the pvc use silicone instead. Once it dries it holds good but if you want to take it apart just give it a good twist. I've done my drain plumbing this way for years!

Thanks a lot for everyone's input~!

you definitely want to use glue if you are doing the herbie style drain. there is going to be some pressure inside the pipes if you do that. you are restricting the flow which increases pressure

but it can't be that much pressure right? cuz I put the gate valve pretty much right after the bulkheads plus I couldn't take em apart so I just left it the way it is and put silicone on every joint. I hope it's ok.............

are you straight up NOT going to glue any part on the drain? or anything after the valve?

if you do not use glue I will bet you money you will not be happy. Seriously lets be professional about our work ask a plumber, they will tell you exactly what I've already told you. Is it the 6 bucks or do you just want to be able to remove it.

typical - every one says glue, but then one guy says silicone and that's what the op goes with.

oh, nano-reef.

I say you use peanut butter... that way when you want to take it apart later you can stop for a snack if you get hungry.

Well.. first of all you are no help so how about instead of flaming and wasting your time you go do a water change or something. FYI I glued the parts I could but I used silicone too cuz some joints were put in too far in that I could not take them out. Something you would've understood if you actually read the whole thread....

Oh, nano-reef

I mean come on...... you are a moderator? You dont say anything and then you find something to ##### about to say some smart ass comment? Oh gawd. You are right OH, NANO-REEF

glue.

I glued everything put the pieces above and in my sump. For those, I use the tight fit. Then again, I'm using a bit of a ghetto set up, where the PVC and tank frame are the only things holding the filter sock, so I have to be able to remove pieces of PVC to clean the socks.

Glue it 100%

Dont be afraid of the chemicals, you will be fine and they dry in an hour.

Also take what people say online with a grain of salt.

don't glue the drain standpipe to the bulkhead. No reason to do so, and the ability to remove the pipe helps with cleaning the overflow. Its not like it will leak.......

As soon as I glued one end I could pull the other end out so I ended up gluing all of the herbie gate drain pipes but the top emergency I couldn't because they were way too tight and I didn't want to crack the tank by forcing too much pressure to take off the pipes. I don't use that emergency pipe at the moment and there is not pressure like the Herbie drain pipe cuz there is no valve to restrict flow.

Plus I glued all the smaller return pipes and everything seems to be good running for more than a week now. Anyways online reef people seem to say purple primer is NOT necessary but the guy at the hardware store told me they are absolutely necessary. I did use them but I'm wondering........

PVC primer is mostly acetone, the purple is just a dye to help you see where you've put it on the pipe since acetone evaporates so quickly. It won't hurt anything once it's cured.