Do I need a under gravel filter with my Rena xp1

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Do I need a under gravel filter with my Rena xp1

by Robert
(Long Beach ca,)

I have a 50 G fresh water tank I'M starting. I'M using a Rena xp 1 .Do I also need a under ground filter?..... Thanks Robert
A: It never hurts and it is about the cheapest filter you can use for any aquarium.

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Do I need a under gravel filter with my Rena xp1

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Oct 24, 2011

Additional comments
by: Paul

The direct answer to your question is that it depends on your stocking level. If, like a lot of folks, you have a heavily stocked or over-stocked tank you need all the bio-filter area you can get. More is definitely better in this situation. The bacteria will expand to meet the bio load but may need more area than the tank & xP1 has to offer.

The reason I recommend & use a reverse flow UGF setup is the extra surface area that you get out of your substrate for bacteria colonies. In a down flow (normal operation) UGF you have bacteria growing only on the top of the substrate. In a reverse flow you have bacteria growth on the bottom as well as the top of the substrate. In effect you ALMOST double the surface area of your BIO-filter and don't use it as the mechanical filter which keeps your tank cleaner.

You also have bacteria growing on the filter sponges & carbon in your xP1 but that mostly gets destroyed when you clean the sponges & replace the carbon every month.

IMHO, it is impossible to find another bio-filter media that has the same surface area as a UGF plate & substrate and is as economical. The "rings", "stars" or other designs that claim to have large surface areas clog over time and must be replaced as they are NOT cleanable. For example, Sintered glass rings have the largest surface area of any filter media on the market BUT they clog quicker than any other media on the market (as little as 4 to 6 weeks from some estimates) and are expensive to replace.

When you vacuum 1/3rd of your substrate a month during maintenance you remove a lot of excess "old" bacteria and allow "young" vigorous bacteria to grow, thereby "renewing" your bio-filter every three months without any cost other than your normal water change. Which, by the way, is about how often you are suppose to change the "high-tech" bio filter media.

What makes this beneficial is 2-fold, Low cost PLUS you only remove 1/3rd of your bio-filter a month instead up to 90% of it every 3 months when you replace the high-tech media.

Hope this helps.

P.S. Most of the bad reputation that UGF's have gotten is from improper maintenance of down flow setups.

Oct 22, 2011

UGF a plus
by: Paul

IMHO, a under gravel (when setup as a reverse flow) is a great addition to any tank. I have a 55 gal FW & a 100 gal SW FOWLR and run reverse flow UGF's in both. I have a pair of Rena xP2's running my 100 gallon and a Magnum 350 that I picked up used for my 55. What I've done is use the canisters to drive the UGF's and act as scrubbers to keep the mulm from building up under the plates.
A: I also agree due to the low cost and high benefit of the UG filter. Also Rena makes a very versatile system that is still available. EDITOR

Use 1 course pad, 1 med pad, 1 micro pad and a carbon bag in the xP1. Make SURE you run 2 or more fine airstones in your tank (more is better) and keep them away from the xP1's intake.

My SW FOWLR has been running for 5 years with this setup and I have never lost a fish or had to tear it down to clean under the UGF. I can check under the plates since my stand is open on top. Great for keeping an eye on whats going on under the substrate.

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Do I need a under gravel filter with my Rena xp1

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Do I need a under gravel filter with my Rena xp1