# Use undergravel filter in 100 gallon, or not?



## Elle (Oct 25, 2010)

I'm going to be starting up my 100gal fancy goldfish tank pretty soon, and plan to have it planted with an ecocomplete/gravel substrate (yes, you can have plants with goldfish). The tank came with a 'homemade' undergravel filter as well as a big canister filter, but I'm seriously considering skipping the UG filter altogether and just using the canister filter. 

The UG filter was previously used for saltwater, and while it looks clean, I'm not sure that I want to reuse it in a freshwater setup. I've also been told that a UG filter isn't compatible with eco-complete. However, my current 29gal goldfish setup has an HOB filter and an UG filter with plants and seems to work OK. No plant substrate, though, just gravel. Another reason that I'm leaning towards not using the UG filter is the PITA factor involved in cleaning underneath it every so often.

Anyone have any advice? Should I keep the UG filter for the extra filtration it gives? Does the ecocomplete work with fancy goldfish with a layer of gravel on top? Barebottom tank not an option for me; I hate the look.


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## hgi (Jun 13, 2010)

No don't use the UGF, they're from the 80's and can be a dangerous ticking time bomb for your tank.


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## hp10BII (Apr 23, 2010)

I would skip the undergravel filter altogether, goldfish or any other kind of fish. If you have to use it, I'd use powerheads to drive the water. If I wanted extra filtration, my preference would be another canister or an hob.

I'm not sure about ecocomplete in an undergravel filter setup. Some of the particles are pretty fine and I'm guessing that it would slip through the veins of the plates. Gravel not so bad because the grains are larger, so if it was a PITA to clean before...

Never could gravel vac ecocomplete either, particles were too small and just kept sucking up lots of sand. I'd stir it up by hand and use the siphon to clean up water borne sediment.

What kind of plants will you be planting that needs a good plant substrate? I think your goldfish will eventually stir up the gravel into the ecocomplete and it'll be all mixed up eventually anyways. Maybe black gravel with ecocomplete or flourite with similar coloured gravel?


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## Elle (Oct 25, 2010)

Thanks for the advice, I'm happy to turf it. I'd rather use the canister and maybe an extra HOB if needed.

Most of the plants I'd like to add would probably be fine with just gravel substrate or none at all (crypts, anubias, java fern/windelov tied to driftwood), but I kind of like the boost the planted ones get from the ecocomplete, although the way my goldfish dig in the gravel I would probably be better off with just fertilizer tabs...


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## TCR (Jul 13, 2010)

i would pass on the undergravel too.. i would get a rena from pets and pond.. free freight over 200$ and the cheapest i found anywhere else ive looked


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