Canister Filter Connected To Undergravel Filter

[Mark Z.]

Has anyone ever tried connecting a canister filter to an under gravel filter?
 
I've had two Fluval canister filters and and under gravel filter running on my 48 gallon aquarium for many, many years. I know many are opposed to under gravel filters, but I have never had a problem with it.
 
I was thinking about possibly connecting the intake tubes of my Fluvals to the under gravel filter, replacing the two airistone tubes. Not sure, just toying with the idea. Has anyone ever done this?
 
I would have to get some type of adapter to allow the smaller diameter intake tubes fit into the larger under gravel plate holes. Then, all the water would be pulled through the gravel and up into the canister filters and back into the tank.
 
Anyone see any drawbacks? The only thing I see is that there would be no direct intake from the open water.
 
Thoughts?

 

[SherLar]

   I like the idea, though I'm no engineer and have no advice on how to accomplish it. When you figure it out, please let us know how. I love under-gravel filters and have them in all my tanks, including my water garden. I also use hang-on-back filters with bio media on all my tanks, but have simple aerator pumps connected to mt under-gravel filters. I use poly fiber instead of activated carbon. I believe they reduce the frequency of water changes.

 

[ShinySideUp]

You don't give the flow-rate of your canisters but I would suggest they would be far more powerful than air-stones and riser tubes and you might end up sucking all sorts of crud out of the substrate and dumping some of it back in on the top. Just a thought.

 

[Mark Z.]

I have a Fluval 305 and 406.
 
I am counting on sucking all the crud out! But, I think it will be caught in the filter sponges and I can get rid of it when I rinse them out. I don't think it will get back into the tank.
 
I will let you know if I do it!

 

[Lateral Line]

I think the adaptor you mention will be a necessity otherwise the water will be easier to suck DOWN the uplifts rather than up as it should. The lack of movement through the gravel then will likely kill off at least some of the beneficials you have there at the moment. Correctly done, it will work as if a powerhead was installed on the uplift.

 

[Mark Z.]

I would prefer to have the adapters at the BOTTOM. Connect the adapters to the UG plate, then connect the Fluval intake tubes to them.
 
We'll see. Still thinking about it. Correctly done is the key!

 

[StevenF]

Mark, I would suspect that the gravel filter might lower your water flow rate through your filter.  If it drops to much it might cause water quality problems   So I would be careful and possibly have a backup canister on hand in case you need it.  Otherwise I like your idea.  Actively pumping water trough the gravel can potentially help keep mulm buildup in your gravel under control while at the same time maximizing the substrates capabilities at controlling nitrogen and purifying the water.   I have been thinking of doing that on a possible future tank.  But that will not likely be this year.

 

[Mark Z.]

I had not thought of that, Steven. Something to consider.
 
One thing that I was considering was connecting the intake baskets that are currently on the end of the intake tubes to the two extra ports on the undergravel filter. (The undergravel filter has four ports, two for the uptake tubes and two extra) This would allow water from the tank to be drawn into the filter and may help with that lower flow rate you mentioned. For that, I would need to come up with yet more adapters!

 

[Lateral Line]

The large area of the u/g plates coupled with regular aquarium gravel is unlikely to cause flow problems. There will be a load of gunk in the gravel and under the plates, the power filters will pull that out in a few hours though.
 
I installed a powerhead on one of the uplifts in my 48", the u/g had been running for 2-3 years, was not pretty.

 

[Mark Z.]

Haha, I can imagine it wasn't pretty!
 
I can see the underneath of my gravel filter from the cabinet below. I sometimes take off the tubes and stick the gravel vac on and siphon out some of the muck. 

 

[Lateral Line]

>>> from the cabinet below
 
Never had that capability, always had polystyrene tiles under the tank, and plywood under them. Neither being well known for transparency.

 

[Phillysailor]

I've built my own in-tank canister filters from a single section of 4" PVC pipe... One sucks from the surface and just underneath and creates flow in the tank (Maxijet 1200) and the other (Maxijet 600) draws from the bottom and pumps into a grid of 1"PVC pipe perforated with small drilled holes and buried in the substrate. They seem to work well, and the substrate seems ok so far. Course its only been a few months!

 

[Danek]

Hi everyone.
I read all your suggestions and comments but no one confirmed that this will work or I've missed something lol.
I'm upgrading from 55 gal to125 gal and planning to use two same size canisters instead one big one for all. Let's say two 100 gallon tank. My idea is to connect one as normal and other into DIY undergravel system made of 1/2 inch PVC pipes with holes .
Anyone have done it and you think that would work better as to clean tank? It's a worth a try? No possible damage to canister connected to UGF? It's been 2 years from last comment here so I'm assuming that someone tried it

 

[AbbeysDad]

I think the under gravel filter is hands down the best nitrate factory resulting in the worst water quality. Fish/plant waste and uneaten food gets pulled in where it decomposes to pollute the water.
I've been in the hobby since the 60's and back in the day the UGF was all the rage...inexpensive and a great bio-filter. However, without routine and significant gravel vacuuming (which is difficult if not impossible in a heavily planted tank), they are just plain awful. You'd be far better off without the UGF and with a sand substrate.

 

[Atr0pos]

I have an UG system connected to my filter. Connecting the two is really easy. Take the hose from your canister filter as well as the UG tube to your hardware store's plumbing section. They'll help figure out the reducer, connectors and sealants you'll need to connect the two. I prefer using flexible tubes in the tank, and I have a PVC plumbing system with returns leading from the back of the tank into my sump. You need large substrate to get this to work effectively. Sand and fine gravel will reduce water flow. Waste and dead plant material will break up in the substrate and will then get filtered out in your canister or sump. I haven't had issues with nitrate and bacteria balance or ammonia levels, and my water remains clear.