Need more sump capacity for backflow... how? Dual sump/fuge tanks?

hocky

hocky

Member
Currently, I have a 20g sump set up and I maintain about 7 inches of water in it for proper functionality of my skimmer and less bubbles from the return. The problem is, though, that my power outage backflow is 15-20 gallons. Obviously, that is going to overflow my sump with only ~8-9 gallons remaining capacity. The obvious solution is to find a 40 gallon tank. Sounds like an awesome plan, but I cannot get it under the stand of the running tank since it will not fit through the doors. It seems that my only solution is to run two 20g sumps. Obviously, this now poses the problem of uneven backflow and having to top off two tank. What does everyone think?
Potential set up is attached. The DT is corner overflows, each overflow goes to a different tank. Return pump is between the two tank, its intake is a T that draws from both tanks and the pumps back to the DT. Thoughts? Suggestions? I am open to any solution as long as it is possible. lol
 
bronco300

bronco300

Active Member
seems doable...but i think i would prefer to drill the tanks and connect them that way...instead of having two drains to each side of the 20s to the middle...i would think itd give a bit better contact time with any macros etc to have to run from one side of the first 20 all the way to the far end....?
 
hocky

hocky

Member
I thought about drilling the tanks and connecting them together, but I cannot think of a way that it will ultimately give me more backflow capacity unless I run the second tank nearly empty w/ just a couple of inches of water. That, of course, is problematic because of evaporation.
 
bronco300

bronco300

Active Member
can you not drill a tiny hole in your return pipe under the water level so it'll stop the syphon?
 
hocky

hocky

Member
Originally Posted by Bronco300
http:///forum/post/2503938
can you not drill a tiny hole in your return pipe under the water level so it'll stop the syphon?

Done. Even w/o any syphon at all, I get a lot of water from my corner overflows.
 
bronco300

bronco300

Active Member
ahh...and for what reason would drilling the two together not work still with a small difference in water levels in both with a bulkhead?
if you are thinking syphon to return pump what if somehow the pump lose syphon to one of the sumps and not the other?
 
hocky

hocky

Member
hrm.. I was thinking bulkhead toward the top of the tank. If the bulkhead was in the middle, that would probably work fine. I think that would definitely be the best route.... I'll have to look into getting tanks drilled.
 
bronco300

bronco300

Active Member
go to menards and get diamond bits...made by tool shop...just start drilling away, and use a cooling liquid constantly to keep the bit and glass cool...i just ran water over the tank constantly.
 
wattsupdoc

wattsupdoc

Active Member
Somethings not right here at all. According to your profile you have a 55 right? You shouldnt be getting 20 gall. of backwash with a 55, no way no how. Post up some pics and lets see whats wrong. I'm all for doing more sump space, just draining 35% of your tank volume isnt going to work. You wont be able to stock the top 1/3 of that tank. Also, you MAY be able to temporarily remove the center brace, then replace it. Or even do away with it with some creative bracing. I've done this exact thing before on another 55.
Find/fix the problem, then deal with the sump/fuge.
 
mckaax

mckaax

Member
you back flow shouldn't be that much. I am guessing you have a 6ft tank? I have a 90 with only about 4 gallon of back flow.
 
hurt

hurt

Active Member
In a 55 gallon you should have no more than 3-4 gallons backwash, unless you have your returns lowered in your tank, in which case you will need to drill an anti-siphon hole just below the surface of the water to stop it. Or you can make sure your returns are just below your water surface in your DT.
On to your diagram. You will have problems with it the way it is currently set up. If I were you I would raise the fuge(on right in diagram) 4 or 5 inches then put a bulkhead in the refuge tank at the top of it and make this bulkhead gravity drain into your sump(return pump chamber). Do you have an external pump?
 
hurt

hurt

Active Member
To figure out the backwash you just need your tank dimensions and then plug into the following formula---(LxWxH)/231. For the H use 1, as 1 inch is typically the most your DT will drop to the height of the overflow teeth when the power goes out. So the length and width of your DT is all you need to figure out how much excess water will drain when your return pump turn off.
Just make sure your fuge is higher(4-5 inches)than your sump(so gravity will allow it to drain into your sump chamber with the bulkhead to your return pump.
 
wattsupdoc

wattsupdoc

Active Member
Raising the fuge will do NOTHING to help with backwash volume. Those are good setups IMO, though. But if backwash space is the issue, you wont gain a thing, actually probably loose some. My 135 With 2 corner overflows doesn't drain but about 10 gallons when shut down. I would try to fit a single larger tank in there somehow if it were me. A 55 would be ideal size IMO.
 
hurt

hurt

Active Member
Originally Posted by wattsupdoc
http:///forum/post/2506411
Raising the fuge will do NOTHING to help with backwash volume..

I NEVER once said raising the fuge would help with backwash. What I said is if he wants it to function properly and drain correctly, and not have water overflowing out of his tanks, he will need to raise the fuge. Otherwise how will water go from the fuge to the sump, and balance the flows from the two overflows to the return pump. The return pump MUST take from only one outlet(bulkhead), not two like his diagram. You will never match flows that way...And only because of that his design is not a good set up IMO...
 
wattsupdoc

wattsupdoc

Active Member
Sorry Hurt, wasnt tryin' to jump you or anything.
But his issue was too much backwash.
I agree raising the tank will work for the flow through it, but so would drilling it with a bulkhead at the same level he's running the current one, connected to it. Without raising it. As long as the drain drains into both and the pump pulls from one or the other as you stated. I just didnt want himm to think that the raised fuge w/ bulkhead up high would solve his backwash problem.
 
turningtim

turningtim

Active Member
Raising the fuge will not allow you to use the fuge for any backwash room. B/c it will always drain to the lowest point. I'm curious why you drain so much water from the DT. Do you have stand pipes in the corner OF's so it doesn't drain the entire OF box?
You can drill both tanks maybe about 3-4" down and use a pipe on the fuge side to maintain water level (it will be adjustable) or you can connect the tanks via HOB OF. I have done it both ways and both work just fine.
If you decide to drill you will only need one bulkhead. You just need to make a 2" spacer (PVC pipe) that will fit in between the tanks and add another gasket to the nut side of the BH.
As Hurt said even at 2" loss out of the DT you shouldn't have a great deal of backwash....
72" x 18" x 2" = 2592/231.... = 11.22 gallons
HTH
Tim
BTW why not use 2 29 gallon tanks. Should fit and will give you greater water volume.......
 
You must log in or register to reply here.
Top