To remove or not to remove the under gravel filter UGF that is the question?

Question

I clean and maintain aquariums for a living. Today I visited a new customer for the first time. They have a 37 gallon tank, this is really deep, 30x12x25. It looks like two 20 longs stacked on top of each other. Poor oxygen exchange is just the beginning of this tanks problems.
It has two filters, one is an under gravel filter. It also has a Tetra Whisper 1 power filter (similar to the current PF-30).
There's a large school of 11 black neon tetras and 12 black skirt tetras. Additionally, there is a small school of three julli cory cats. There were five originally, but two died. One black neon also died recently.
This is what prompted the call, three deaths in a week. The tank is in an advertising agency and they want it to look good...
They like the black and white theme...
The tank has a moderate amount of brown algae on the walls, artificial plants and not much on the gravel.
A slight white haze indicated a bacterial bloom.

Testing the water, I found ammonia at 0-.25 ppm, it was borderline, definitely not 0 ppm. No nitrites. The Nitrates were at 40. The thing that troubles me the most is the pH is very low. Even after a 25% water change, it still showed 6.4 at best. From the tap, it was 7.0. No surprise that I sucked enormous amounts of brown and black debris from the filter plate as I exposed a little at a time and cleaned 1/2 of it. It was the grossest thing I've seen/smelled in a while.
I plan on doing the other half next week, I didn't want to do too much at once and cause a mini-cycle. I also know there's plenty more filth down there and it will still be there after cleaning for a second time.
I want to avoid tearing down the tank and removing it. It may very well pollute the water so badly, I'd have to restart it. Obviously it would be bad for the fish... Do I clean it the best I can and let it be? This is my first plan. Perhaps with regular maintenance, the UGF will be fine.

I have customers with UGFs that are fine and would yield little debris if I cleaned the filter plate, because of very frequent water changes.
UGFs do work... if you take care of them. This one wasn't taken care of at all.

Answer 1

I would remove the UG filter, and have them get an Aquaclear 110. I know it sounds big, but you can adjust the flow so that it is not so bad. This tank needs a large filter since they aren't going to be giving it good care. They should be able to get a 110 for around $50-$65. I would run the little hang on the back filter while the larger one runs for the first 3 or 4 weeks. You should just continue to clean the tank, doing 50% water changes once a week until nitrates go to near zero. I would also make sure to place a large carbon pillow in the AC110 to adsorb all the funky smells and to clear the water up.
Edit - One of my tanks has a UG filter and it works great for me too, but I also take care of it, as you do.

Answer 2

Just another option for you, but have you considered pulling the filter plate and cleaning as you would need to anyway, but putting the UG back, but using a reversible powerhead to operate it? This will take oxygenated water from the top of the tank, push it down the tube, and blow the water up through the gravel. This would still provide good biological filtration, and circulate the oxygenated water to the bottom of the tank (needed for a tank that deep), but this system will also be much less likely to build up debris or anaerobic pockets under the filter plate. By blowing the water upward through the gravel, it keeps particles in suspension longer so the power filter can remove move.

It also sounds like someone at this company should be shown how to use a gravel vac.

Answer 3

How many fish do you have and what kind of fish are they. It almost sounds like you are overstocked. I am not sure about the UGF, I don't really like those. They have never worked for me. I would use a gravel vac and change 35% of the water. Do this every other day until the ammonia is back down to 0ppm. I can not stress enough, be sure your tank is not overstocked. Also, never feed more than the fish will eat within 3 minutes. These are usually the causes of high ammonia levels.=

Answer 4

yea remove the ug filter because the problem with this is that they are not as effiecent as canister filter plus they fock up bad and makes tanks dirty even more

REMOVE THAT IS THE ANSWER!!!!!