My 400g build

[purdy]

I didn't read a lot of this......but what ever you do make sure you have a way to separate the two sumps. If you put slip bulkheads and glue PVC pipe in them then your sumps are forever connected. Having a dual sump system myself I can tell you there are going to be times when you need to remove one sump for whatever reason. Also I think 1.5" is too small of a bulkhead size. I can't remember the exact math I did when setting my sumps up but I wanna say that a 1.5" bulkhead didn't have enough flow through it to supply enough water for the DC12000.

[diegoluv]

I didn't read a lot of this......but what ever you do make sure you have a way to separate the two sumps. If you put slip bulkheads and glue PVC pipe in them then your sumps are forever connected. Having a dual sump system myself I can tell you there are going to be times when you need to remove one sump for whatever reason. Also I think 1.5" is too small of a bulkhead size. I can't remember the exact math I did when setting my sumps up but I wanna say that a 1.5" bulkhead didn't have enough flow through it to supply enough water for the DC12000.

Why not just unscrew the nut on the bulkheads from the inside of each sump to separate them?

[purdy]

Because I'm not into wasting a bunch of water. My larger sump can store the volume of my smaller sump just fine and my smaller sump can hold half the volume of the larger sump and the other half can fit in the tank. So I can have either sump empty without having to waste any water. Unless I'm missing something you can't do the same, unless you pump the water into another container separate from the system. Also, if you can remove the nut and separate the sumps that way that means your bulkheads are backwards. Again I didn't read to much of this so I could be missing something. All I know is 400 gallon is a metric **** ton of water, a little planing, research and caution would be in your best interest. And lastly, if you're smaller sump came from Tri-City tropical fish used then it has a crack in it. It's not all the way through but it's enough to where I wouldn't trust it with a 400 gallon tank.

[unbereefable]

Running bulkheads backwords makes no difference. As long as the gasket is on the FLANGE side of the bulkead, it doesn't matter where the flange side is, dry or wet.

[purdy]

Everything I have ever read, by bulkhead manufacturers say that the flange goes on the wet side along with the gasket. Nut goes on the dry side.

[unbereefable]

Nope. Been running them backwards for years. Everyone has what they consider the "right way" even Mr saltwater tank, says to run them with the flange side on the wet side. But again, that's one dudes opinion. Although he's has way more expirence than most, doesn't mean he's right, or wrong for that matter. He has what he considers is the preffered method. I first tried it on a sump I drilled. It was tapped for an external return. But needed to make a sharp right angle to get to the pump. Plumbing backwords allowed me to use a street L, and keep the pluming close to the tank. If I ran the bulk with the flange on the wet side, it would've stuck out to far and wouldn't have worked. There's also a few thread on RC about this. As long as the gasket is on the flange side, it doesn't matter it's orientation.

[diegoluv]

Running bulkheads backwords makes no difference. As long as the gasket is on the FLANGE side of the bulkead, it doesn't matter where the flange side is, dry or wet.

+1 what unbereefable said. As long as the bulkhead has a gasket on the flange and the nut can compress the gasket between the flange and the sump/tank, it won't leak.

The way the OP has it setup will work just fine as long as the bulkheads are not over or under tightened and the gasket forms a good seal. If he needs to separate them, he can unscrew the nuts on each bulkhead and separate the sumps. Purdy is right, you may have to drain water but you can always schedule it with a water change so as to not waste water.
As for the size, if the drain is 1.5 inch, and it's a traditional overflow, it will pass just as much water through the bulkhead as the drain will drain. Since there is no suction effect, it will pass even more if anything. However, as I said in my earlier post, a second set of bulkheads is not a bad idea for, at the very least, redundancy.

[purdy]

Meh, I'll go with the manufactures recommendation considering a team of engineers came up with it. But to each their own.

[purdy]

I was more thinking about emergency situations where he might have to remove a sump. When I was planning my tank out I thought about needing to remove a sump in the middle of the night. Both my sumps combined have a volume of 85 gallons at the minimum water level. I never have that much RO or mixed water on hand so I designed my setup to where I can turn ball valves to cut flow to the filtration and then a ball valve between the sumps so that either one can be emptied and removed. If this happens, doesn't matter the time of day I don't have to worry about wasting water. So if it's late and the LFS is closed I don't need to have the system off until I get more water.

Either way, to each their own. And I'm sure bulkheads work either way they are oriented, I'm just to much of a wuss to go against manufacturer recommendations.

[sdnd]

all these suggestions are great. so i wanna make sure i'm doing it right since i'm getting mixed suggestions. currently i have the nut and rubber seal on the inside of the sump (wet side) for each tank. will this work? originally i had the gasket on the outside of the tank. please confirm before i fill up the rest of the sumps.

and to answer the concerns about draining one sump or the other. the only sump i would remove is the smaller one. so, i would shut off the drain for that sump...let all the water drain into the 2nd sump or as much as possible. then i would plug the bulkhead with a plug and then unscrew the nut and then can remove the smaller sump without leaking.

[purdy]

Just ensure the rubber gasket is on the same side of the flange. If you need help with anything let me know and I can offer a hand. Or if you want pictures of my 400 gallon setup for reference then let me know.

[purdy]

Tried to reply but inbox full.

[diegoluv]

You want the gasket on the dry side in your case because the flange is on the dry side.

[sdnd]

Tried to reply but inbox full.

box cleared!

[sdnd]

You want the gasket on the dry side in your case because the flange is on the dry side.

that's how i originally had it...guess i'll redo it again. lol
this gives practice on how to remove the sump if needed...

thanks again for all the advice!!

to qt in the dt or not? that's the next dilemma!