overflow to canister filter
- Thread starter NgaNasty
- Start date
It doesn't work. You have to do something to change it like make sure the overflow is no longer really an overflow and has ful water all the time or feed it from the sump. If I have a client with both I just keep them separate, sump runs independent of the canister.
If you have overflow boxes on your tank and are dead set against using a sump, you have a few options. You can use bulkheads and then cap off in the holes in your overflow box to close off the overflow box, drill holes in the top or back of the tank to accommodate the uptake and return lines of your canister filter.
Overflow boxes come with various plumbing configurations. The overflow boxes on my 300 gallon tank have two holes in the bottom of the box--one going to the sump and the other for the return line. There is a hole in the top of the tank for the return line.
So our return line comes up through the overflow box, turns to the right, and then enters the tank through the top. Our return line for our mechanical filtration is on the left front pipe. Notice how we've drilled more holes on the top of our tank. Two of the holes are for FX-5 lines.
The external overflow boxes on our new tank have holes that could accommodate canister filters. Notice the four holes into the tank near the top of the overflow box. These are for return lines from the sump. (There are corresponding holes at the bottom of the overflow box for the return pipes.) We could, in theory, use these holes for canister filter uptakes/returns.
I think to use your overflow box, you would need to drill a hole in your overflow box into the tank for your uptake line to your canister. It would be a lot simpler to plug off the overflow box and drill two holes in the top or the back of the tank for your canister.
Overflow boxes come with various plumbing configurations. The overflow boxes on my 300 gallon tank have two holes in the bottom of the box--one going to the sump and the other for the return line. There is a hole in the top of the tank for the return line.
So our return line comes up through the overflow box, turns to the right, and then enters the tank through the top. Our return line for our mechanical filtration is on the left front pipe. Notice how we've drilled more holes on the top of our tank. Two of the holes are for FX-5 lines.
The external overflow boxes on our new tank have holes that could accommodate canister filters. Notice the four holes into the tank near the top of the overflow box. These are for return lines from the sump. (There are corresponding holes at the bottom of the overflow box for the return pipes.) We could, in theory, use these holes for canister filter uptakes/returns.
I think to use your overflow box, you would need to drill a hole in your overflow box into the tank for your uptake line to your canister. It would be a lot simpler to plug off the overflow box and drill two holes in the top or the back of the tank for your canister.
The problem with that is if the water level in the tank drops even slightly, there will be no water entering the overflow box. There needs to be a hole from the tank into the overflow box lower than the slots/grids of the overflow box. If I were doing it that way, I'd plumb the uptake of the canister directly into the tank through that hole.
I lose a lot of water to evaporation. The water still flows into the overflow box, because the water level in my sump takes the hit (it has gotten so low that the pump was not covered in water) In a more closed system with canisters, the water level could very easily drop below the slots of the overflow box. Unless provisions were made for a drop in water level, it could be a quick way to burn up a canister filter.
it won't work.
for an overflow to work, the tank needs to "overflow" constantly. this is accomplished with a sump because the pump will be constantly filling or "overflowing" the tank from the sump. this keeps the water level in the tank at a constant, while the water level in the sump changes with evaporation, draining and refilling.
with a canister, the water level in the tank will fluctuate with evaporation, draining and refilling, rendering an overflow useless. meanwhile, water in the canister will remain the same.
i dont know why i would have to drill a hole. i connect the intake of the canister to a bulkhead where a sump intake would normally be but just no pipe running up.it seems like it would be a constant flow. maybe im not understanding what some of you are saying
It can work, I have done it in multiple tanks, just have to watch the water level with evaporation. For systems with large evaporation I use an automatic top-off system to make sure that water is always going into the overflow.
Pics like the OP asked for 
120 gallon Aqueon "megaflow" tank with dual overflows conected via bulkhead fittings a softline plumbing to FX5. I removed the towers on the inside of the tank, they are standpipes behind a 3D background.
120 gallon Aqueon "megaflow" tank with dual overflows conected via bulkhead fittings a softline plumbing to FX5. I removed the towers on the inside of the tank, they are standpipes behind a 3D background.