Undergravel Filter

[Limpet]

I'm new to the forum so please forgive if this questions has been asked before.

I setting up my 135G salt tank after 7 years in storage. Previously I had a wet/dry filter and now I'm thinking about going with an Undergravel filter combined with a mechanical cartridge filter and a charcoal chemical filter and a protein skimmer

I have read all the horror stories about UG filters but I'm still considering the UG because I plan to use a reverse flow. The general plumbing would be as follows. Tank -> Autoleveler siphon -> Mechanical cartridge filter -> Charcoal filer -> Pump -> Protein Skimmer -> UG filter -> Tank.

The only issue I have read about a reverse flow UG is that they still clog, but in the reverse direction, because the mech filter does not filter enough. However, given my setup I just can't see how this could be so. Nothing of any size is going to make it to the UG filter.

Anyone with a reverse flow UG filter have any thoughts or comments?

It seems I hear nothing but praise for the power filters like the Magnum 350. But such a filter could not possibly have the surface area of the gravel bed in my tank.


Oh one last thing, when cleaning a reverse flow UG bed, I would think that if you were to use one of those siphon cleaners that you would create a hole in the bed where the bulk of the water flow would then pour out. Making it difficult to get the gravel to settle back down. Any issues with cleaning?

Thanks,

Tesla

 

[Limpet]

Have I posted to the wrong category?? I have not received a single response?

Thanks,

 

[Thomas A. Anderson]

I personally have no experience in UGF's but perhaps if one of the admins move it to the hardware section you might get a better response.

 

[William]

Ok I've moved this. Like CCL I have no experience with UGF's, its sounds like a complicated arrangement you would have to set up. I'll send a message to our two saltwater moderators - whacky and great lakes, better still Great Lakes is the moderator of the equipment section too! they can probably have a browse through your idea and advise on any problems you may encounter as they perhaps will be most qualified. Why exactly do you want to use a UGF anyway, what is the advantage? I see none all I see is possible failings? How about using a DSB - deep sand bed a few inches deep to do the filtration on the base of your saltwater tank instead? Biological filtration can be better than mechanical, just make sure you get some livesand .

 

[Limpet]

I guess my thinking is "Why waste all that surface area, only to try to reproduce is externally in box or canister filter".

I also suspect that the tank might overall be a cleaner environment as there will be a gently flow upward out of the gravel bed into the tank. This will hopefully promote the capture of waste by the mechanical filter which is pullng water from the top of the tank.

Tesla

 

[whacky]

Hi Tesla,

Sorry for the delay in answering you i been a bit slow on the uptake the last few days not been well.

From some of the equipment you named i am guessing you from the USA so i cant comment on specific items of equipment.

However generally undergravel filtration is not reccomennded these days as its seen as a bit dated however thats not to say it cant be used. Its that generally more natural methods are used.

To advise you better could you tell me wether you are intending to have a fish only system or having a reef tank with corals etc in it. As this to some extent dictates the way you should go with filtration.

I personally havent used a reverse flow ugf when i set up my first tank i was advised against using ugf as eventually it will clog up and you will end up with high nitrates and have to strip the tank down to clean it.

A better option if you dont want to go down the road of sumps etc would be a fluidised bed sand filter, this basically is a tube of sand which goes after the mechanicl filter. The sand gives a massive area for bacteria to colonise and filter the water.

Hope thats of some help dont hesitate if you have more questions or if i have missed something.

Whacky

 

[Limpet]

whacky,

I was planning just salt water fish only. As for the equipment it is all bodged together, home grown stuff. Yes, I'm in the USA.

With regard to the sand bed, I see that being the same as what I propose. The sand bed is after the mechanical filter just as the gravel bed.

When I first read of the reverse flow concept, it just struck me as the the right answer, curing all the ills of a UG filter.
I have not tried it, so I can't say for sure. It seems many have been fightened off from using UG filters because of the clogging issue, but this seems resolved with reverse flow.


Thanks,

 

[Great Lakes]

Hi Telsa, As Whacky has said, what type of marine set-up are you shooting for, and what do you plan to keep in it. Much easier to give you an accurate answer with a good visual in my head.

Sorry about the delay too, I am usually on two or three times a day, but just passing through all the holidays have me off track.

 

[Great Lakes]

Well, it looks like I wasted a post eh?

Underwater filters have been getting flack for having dead spots. In a marine system, the substrate is usually finer, and has a tendency to get hard spots in it that doesn't allow water or oxygen to penetrate and keep the biological process going. A fluidized sand bed filter might be a good option for you. This way you can have a normal sand bed that crabs and such can feel at home in. I would still consider running a sump on your system if only for the additional volume of water. What kind of skimmer are you running?

 

[Limpet]

Great Lakes,

Was just planning to use Dolomite as the gravel bed, but perhaps a nice white sand, tropical like, would look nice as well. I would not think sand would be as permeable as the dolomite. Although I know pool filter have used Sand as the element for years, and I see the water drain away from the sand on the beach easy enough. hmmm, it just seems so dense.

But Sand or Gravel, this is a 72" long tank and there will be lots of surface area, especially with an inch or two of sand.

Why do you think a sump is necessary? Volume of water??? I had one before, but I don't think I would need one if I go UG.

I have a home made protein skimmer. It is about 4.5 feet tall and 3" in diameter with a 1" tube down the center. I use a air stone near the bottom. The pump, pumps the water near the top of the skimmer where it enters the one inch tube which directs the water down to the bottom of the skimmer. There the water combines with the bubbles and makes it way to the top were it overflows back into the tank. Now, it would overflow into a tube that would take the water under the gravel......I mean sand bed.