general filtration question

[tigerbarb]

I have a concern ...
My 40 gallon tank with semi aggressive ( what i call community tank) has an over the back filter strong enough to use alone. It is a mechanical and biological filter combined.
i choose to add with this an under gravel filter with power heads.A great biological filter.
I think they increase the oxygen flow and kep my tank water clearer.
Despite all the negative things you hear about them i never had a problem with it on any of my tanks. My question is this...
Should I or Can I add some kind of substrate to the bottom of the under gravel filter so it can also help in its filtering procedures?
is it mandatory?
does it change anything?
would it be beneficial to my tank?
should i at this point not disrupt it to change it?

i am moving at the end of the month locally but still moving if i had to add the substrate i feel this is the best time to do so
can some one please see my need for advice that the professions cant give me?

 

[loganj]

I'm not sure I understand your question. Are you asking if you should add substrate underneath the UGF plate? If so, then no, I would not do that. I'm assuming you have gravel covering the UGF plates. If so, that's all you need. One way to keep the benefits of the UGF while mitigating the chance of having problems with it is to run it in reverse. Instead of pulling water down through the gravel, you reverse the PH's and pump water down under the plates and force it up through the gravel. This eliminates the problem of food/detritus building up under the plates and rotting while still maintaining the biological capacity. Running it in reverse will also help keep uneaten food suspended where the power filter has a better chance of getting it. You'll need to have some sponge prefilters on the PH's if you decide to go this route. JMHO.

 

[TankGirl]

I agree. There is no reason to succumb to popular opinion and ditch the UGF if you are happy with its performance, but I would not add any substrate beneath it, as it will make it harder for it to do its job. There is a space under there for a reason, so I'd not change anything, but the reverse flow UGF is a wonderful idea, and I suspect when you take down the tank and see what has collected under there so far you may find yourself in agreement!

 

[tigerbarb]

thanks guys
what iw as actually asking
is maybe i was abit confusing in my approach is that i heard to put charcoal underneath it?
is that at al even possible
and how do i reverse my powerheads?

 

[TankGirl]

Don't put charcoal under the UGF. Charcoal will trap tiny debris from the tank only for about a week, then after that it is clogged and becomes a mechanical/biofilter, but would not be a good choice under the plates.

We are assuming that your UGF utilizes air stones and air pumps to create uplift to draw water from the gravel to underneath the plates. If you have powerheads mounted on your uplift tubes, forcing water DOWN the tubes and up through the gravel into the tank, then you already have reverse-flow UGF.

 

[malkore]

They also make charcoal inserts for the uplift tubes on a UGF...problem is they cost about a $1 each, and charcoal's only 'active' for 7 days after it's submerged.
They need to make a refillable version of these...but I have yet to see them at any LFS or chain store. I bet you could carefully cut one open and make something that worked though.

But if you did a reverse UGF, these carbon inserts wouldn't be beneficial...better to just run a bag in your HOB filter instead.

And for the record, UGF's aren't 'bad'...its just that you have to pull the plate at least once a year to clean it...and that's just a big pain that a lot of us feel outweighs the benefits.

 

[tigerbarb]

my power heads run into the tank and from the tubes
so water go down in the plates and up the tubes through the power heads
how doi reverse this?

 

[TankGirl]

Tiger barb - I want to be sure I understand - you have powerheads attached to the uplift tubes so that the water is being pumped down the tubes and underneath the plates, so that the water flows from under the plates UP through the gravel into the tank?

 

[malkore]

No I think he's got the intake of the powerhead on the uplift tubes, so it's normal flow direction, just a powerhead instead of an airstone.

To reverse the flow, you need to flip the powerhead 180 degrees, so it pulls water in from the aquarium, and blows it down into the tube.