# Using a canister filter as the pump for a wet dry sump



## Garyvermillion2 (Feb 2, 2019)

Has anyone connected the intake of their canister filter to the sump of their wet dry to use it as the pump? Overflow into filter bags, through bio media, chemical media and more bio media inside canister, return to tank from canister.


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## Deeda (Oct 12, 2012)

I have never used a sump but I wouldn't recommend using the canister filter that way. 
One reason is that having the intake in the sump and the output in the aquarium is that there is no way to guarantee you will get the proper balance between inflow and outflow. 
A 2nd reason is that in the event of a power outage and how low you have the output, it could suck back water into the sump via the output and possibly overflow it. 
A 3rd reason is that you may have difficulty priming the canister filter as most of them require the top of the filter to be installed a certain distance below the water source.

Were you just trying to avoid using a separate water pump and just use the canister filter for duo purposes?


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## Garyvermillion2 (Feb 2, 2019)

First canister filter I've owned and a bio-film built up on the water surface quickly. I built an overflow/weir that works quite well with the canister however it does not float and is static. It only takes a pint every couple days to maintain proper water level and, if the water level drops there is enough port openings at the bottom of the overflow to supply the Canister filter, and the skimming action just stops till I fill up the tank. The way an overflow works with a wet/dry filter the tank water level is controlled by the position of the weir, the variance in water level occurs in the sump, you add water to the tank and it stays at the same level in the tank, the sump water level rises. When there is a power outage the weir keeps your tank water from draining into the sump and if you install a back flow valve in your return line, very little water drains back into the sump. Without a back flow valve in your return line the water level of the tank will back-flow until the return line breaks siphon, and this is the reason return lines are installed at a very high level in most wet/dry systems. By design the sump will hold the back-flow water that drains from the tank in a power outage event.
Your first concern about balancing the flow is not an issue, the wet/dry sump flows at the rate of the pump, and since you are using the canister filter as the pump, the water returns to the sump at the same rate as the pump sends it into the tank.
Its a pain to break down the canister filter to clean it up, so I want to catch all of the solid waste I can in very easy to service filter bags hanging in the sump, that are turned inside out and rinsed clean and returned to the sump. This should eliminate the need to break down the canister filter for very long periods of time because it intercepts the solids. The canister could be packed with bio balls/media and no pads, more bio-media and carbon in the wet dry.
Your third point is where I think it will have to be proven with an experiment because I think if I were to tie the canister intake to the sump with a bulkhead fitting at the lowest point and used a back-flow prevention valve on the return line, the canister would not loose siphon and would start right back up in a power interruption event. This may be tricky, and the Canister may indeed need to sit lower than the sump water level. Getting it primed the first time may be impossible.

Basically I have a sump in storage, the canister filter is a great pump and a bitch to clean, it sucks for keeping the surface water film cleaned up, was thinking of using the two filters as one, and was just trying to figure out if someone else has already tried.

Thank You Dee for conversation.

Gary


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