Underwater Gravel Filter

[Kurt]

I am getting ready to purchase an 120 gallon fish tank after 20 years on the sideline. Based on various readings, it appears that underwater gravel filters are looked down upon now. Maybe I am being paranoid, but I am afraid of dropping something heavy in the tank when cleaning it and cracking the bottom. Is there anything out there for padding on the bottom of the tank or should I not worry about it?

Kurt

[Brhino]

Are you not planning on having any substrate? Sand or gravel should absorb and distribute any impact that might otherwise crack the glass.

[Kurt]

If by substrate, you mean rock...then yes there will be rock on the bottom of the tank.

Kurt

[Brhino]

but no fine material like gravel or sand?

A lot of people who are putting heavy rocks on the glass (or close to it) put a layer of egg crate or cut PVC pipe between the glass and the rock to support it and spread out the weight. That won't help if you drop a heavy rock directly on the glass I guess...

[jbstc03]

You should be fine with the rock, just dont drop anything period. But with that being said, you can use egg crates just cut em flat if you absolutely insist on having something. But for me as said, dont need to worry and +1 on not using an undergravel filter. It is for the old schoolers and more of a pain IMO. get a good canister and you will be happier or a wet dry filter.

Assuming you are using an aquarium gravel = You said rock

[Kurt]

Yes, you are correct....I guess rock was a bad description. I do plan on putting gravel at the bottom of the aquarium. As far as a canister filter, I am going to purchase a Hagen Fluval Canister Filter FX5 (924 U.S. Gal./H).

Kurt

[toddnbecka]

UG filters are just as good as they ever were (or weren't, depending on your personal opinion), the only difference in 20 years is the availability of more different filtration options. I used UG filters in most of my tanks for years, still do in several, but have been changing substrates from gravel to sand which they don't work with.
I recently picked up a used 125 that included a UG filter, 4 18"x18" plates. Needs new uplift tubes, the old ones were opaque and brittle, but you can have it for $20 + shipping of you want it.

[tasneef]

ug filters are good.i always used it and my aquarium is in good condition.actually they are best for beginners.

[Lady Hobbs]

In large cichlid tanks full of rock as you are describing, I would think an UGF with reverse flow pumps would be ideal in addition to a good canister filter. I wouldn't use them if using sand, tho. Of course cichlids do like to dig.

[MCHRKiller]

UGFs have a horrible rap mainly due to improper maintenance, well kept UGFs are very effective biofilters and can be excellent supplemental filters in cramped spaces. On a tank as large as a 120G...I would not trust one to run your tank alone. If you paired a UGF(reverse flow is easiest to keep clean) with a large volume canister(XP4) or a couple of HOB filters(AC110s) then you could have a great filter system.

120G tanks are very heavy thick glass tanks which can take some abuse, if you simply keep a layer of sand or gravel on the tank and safeguard against large rocks or objects falling into the sides of it everything should be fine. With that said you can put some egg crate on the bottom of the tank for extra safety.

[Kurt]

I have never heard of UGF (reserve flow). How does it work. I did a quick search on the Internet, and I am still confused about it.

Kurt

[Kurt]

I understand how it works now. Is it worth doing it?

[Fisharefriends27]

I think the best beginner filter for smaller tanks are power filters. Larger tanks canisters.
I dont recommend getting one.

[Sandz]

I would personally spend the money on a good cannister and a sponge filter for a 2nd option.

Gravel should not hurt your tank one bit putting it in but obviously you wouldnt drop a 20lb rock from 5ft in the air, dont pour gravel from 5 ft in the air and you should be fine.

[dbosman]

I understand how it works now. Is it worth doing it?

The answer is.... Maybe.
There is no conclusive answer to most aquarium hardware questions. There are opinions based on personal experience and preference.
In the case of reverse flow under gravel, it can be perfect for some situations, reasonable for some, not particularly useful in others, and completely wrong for some setups.

Where under gravel filters and reverse flow under gravel filters are properly used, they provide massive bio media areas. Bio media areas can get really filthy.

Understand the Nitrogen cycle, your particular tank setup and fish and you'll have a better idea of what filtration to use.

[toddnbecka]

The advantage to reverse-flow is that the debris doesn't get drawn down into the gravel bed. I had 2 tanks set up with aquaclear powerheads, with sponge blocks inside quickfilter housings, adapted with pvc elbows and vinyl tubing to run the UG filter plates. The prefilters on the powerheads collected most of the debris, but the arrangement doesn't help with surface agitation. I also used a fluval 304 on the 55 and a smaller powerhead and hydrosponge in the 29 to help circulate/aerate the water.
I have a 75 running now with 2 aquaclear 110 hob's connected to the uplift tubes of the UG filter plates. That arrangement prevents any debris from accumulating under the plates, and whatever gets through is collected by the hob filter media. Since that tank houses 3 L-204's that eat wood and poop sawdust a dark brown gravel substrate looks much better than sand would. There is plenty of muck to be siphoned out of the gravel when cleaning, but overall the tank looks clean and the water is always clear.

[Lady Hobbs]

I think the best beginner filter for smaller tanks are power filters. Larger tanks canisters.
I dont recommend getting one.

Yes, but he is not speaking of a small tank but a 120 gallon full of rocks.

[Kurt]

I just ordered the tank, and I am so excited now. I am getting the 60x18x26 tank. I would like to get the 72 inch, but my wife pulled her veto power on me. She rarely uses it. In her defense, I am talking about putting a fairly mammoth piece of decoration in our living room. I cannot wait falling asleep to it. There is just something about the white noise it puts off.

Based on what I have read here and on the web, I am not going with an underwater gravel filter. If I did go with one, I would go with the reverse flow. I can always add them later, if it seems necessary.

When I had my tanks years ago (75, 55, and 29), I never cleaned under the UGF out of ignorance. I remember looking below the tank and seeing all the nastiness.

In the past, I had African Cichlids an a couple red-tail sharks. I am leaning that direction now. However, I am still up in the air. I know some Cichlids can grow fairly large. Part of me whats to go with a lot of small fish, but I would be limiting myself in terms of which fish I can buy.

LOL, Lady Hobbs.....30,422 posts....that is some serious forum posting!!

Kurt

[mermaidwannabe]

Until recently, I had always had UGFs in my tank(s). My most recent tank, a 20-gallon-high coldwater, cycled with a UGF in it and Maxi-Jet 400 powerheads with UGF adapters inside the lift tubes.

I have switched over to an AquaClear 50 hob, because it's easier to maintain and I don't need the powerheads.

With UGFs, one not only has to regularly vacuum the gravel (you do with any filtration system), but you also have to completely tear the tank down every few months and clean underneath the filter plate. And that means having to take out all the gravel to reach the plate, take out the plate and attached lift tubes, the powerheads, etc., rinse everything in tank water, clean the glass on the bottom of the tank, put it all back together, and lose a lot of your beneficial bacteria in the process. I did that with mine, and experienced a small ammonia spike, afterwards.

The AC hob is so simple. Just lift out the media basket, rinse the media, reinsert the media basket, plug the filter back in, make sure it primes properly and restarts the waterfall, and you're back in business.

Even cleaning the filter itself is easier. You just take it off the rim of the tank, disassemble the parts, brush them out and rinse them, gently disassemble the motor housing from the filter box in the direction of the arrow, and clean the impeller and its well, reassemble (very easy to do), return the media basket into the chamber, plug back in and go. You don't have to take out all your gravel and ornaments and plants. You needn't remove anything from inside the tank except for the extension tubes of the filter, itself.

As for the bottom glass panel being sturdy -- any tank above 10 gallons has tempered glass on the bottom. That helps make it stronger, and in the event it doesn break, it won't shatter into millions of pieces like untempered glass would. Of course, you can't drop anything heavy onto it, but as long as you have some sort of fine substrate at least an inch deep, and are careful about gently setting heavier stuff upon it, you won't have any problem.

-- mermaidwannabe

[ILuvMyGoldBarb]

Yes, you are correct....I guess rock was a bad description. I do plan on putting gravel at the bottom of the aquarium. As far as a canister filter, I am going to purchase a Hagen Fluval Canister Filter FX5 (924 U.S. Gal./H).

Kurt

That would be a good choice for that tank. If you want, you could even run the return line to your UGF to keep the gravel nice and clean. Or, if you don't mind doing all the gravel vacuuming, then you can run the intake of your canister off the UGF as well. Either option is IMO a good idea.

[ILuvMyGoldBarb]

, but you also have to completely tear the tank down every few months and clean underneath the filter plate. And that means having to take out all the gravel to reach the plate, take out the plate and attached lift tubes, the powerheads, etc., rinse everything in tank water, clean the glass on the bottom of the tank, put it all back together, and lose a lot of your beneficial bacteria in the process. I did that with mine, and experienced a small ammonia spike, afterwards

All that is actually not necessary. If you are properly maintaining your UGF tank none of that will be necessary. I'm not going to go into the detail and derail the thread, but proper maintenance does not involve these steps.

[Cermet]

I feel that an UGF combined with a reverse flow power head and a canister filter is the best combo filtering system for an aquarium - that way, you can use the canister for its (some say) superior bio-filtering properties (when the trays are filled with bio-noodles) and the UGF to keep the substrate clear (reducing to almost eliminating vacuum cleaning down in the substrate). Surface vacuuming is still needed weekly.

What ILUVMYGOLDBARB said is an excellent idea that I always wanted to try but instead, bought the power heads - that idea is far more cost effective.

Good luck!:hmm3grin2orange:

[Aeonflame]

you can use egg crates just cut em flat if you absolutely insist on having something.

How do you cut egg crate flat?

[Lady Hobbs]

my wife pulled her veto power on me.

LOL, Lady Hobbs.....30,422 posts....that is some serious forum posting!!

Kurt

:hmm3grin2orange: Luv that veto power. Does she have a lot of ink in that pen? :hmm3grin2orange:

I know......I talk too much. Five years of blah, blah, blah!