just a quick few questions regarding filters

[crr]

my sister has a 20gallon tank, but in the last few weeks she has lost most of her fish, i dont knwo what it could be, she doesnt do any tests on the water or anything so i cant tell you the water parameters

she had around 8 fish in there mostly guppies and tiger barbs.

she has 2 airstones running and the only filter she uses is a grate system that goes under the gravel, i dont know how it works (can someone explain it to me?).

Does anyone think she should be getting a proper filter with a sponge and that can make the water flow around the tank.

 

[galen]

i had one of those grates- they're called undergravel filters and they're overrated. trouble with them is if left in the tank for more than six-eight months, they clog up. like, the one i had had to be removed from the tank cause the gravel vaccuum didnt suck up all the slime and crud under there whenever i made a water change every week or so. the stuff under there was disgusting! so, if i were you, id tell her to rip the thing out, buy a good tetra or rena filter, and run that on the tank instead. it will be worth it in the end.

 

[Daudzegier]

The gravel serves as mechanical and biological filtration as the powerhead sucks the water through the gravel, and then through the grate, up the pvc tube, and then out the powerhead. The problem is they clog easy, and you have to clean the gravel to get rid of physical debris. Unfourtunatly this also disturbs all the bacteria. So you send your tank into a mini-cycle everytime you efficiantly clean it. In my oppinion an airline sponge filter works better and is more reliable than this system.

With that said, she could have cleaned her tank to some degree, and sent her tank cycling. This spike in chemistry could have killed her fish.

 

[Rbishop]

She would benefit in many ways from an HOB power filter. It can't hurt to have multiple sources of filtration.

For the record, undergravel filters do not clog easily, especially when driven by power heads, vice an airstone. They do get a build up of fish waste and uneaten food when tank maintenance is not being performed in the correct manner or frequently enough, coupled with over feeding.

If your substrate is to deep, you can shift the location of where the bacteria is, but if you have adequate flow, the oxygen carried by the water will still be available to the bacteria. Once again, things that are in your control. The vac work on the gravel will not destroy or remove the bacteria causing a mini cycle.

If that is the only filtration she has now, Do Not Take It Out. Get a HOB on there and run it for at least 3-4 weeks before removing the UGF,if that is her final decision. Also, get a good liquid test kit that can give you readings on ammonia, nitrite, nitrates and pH. Is she using a water conditioner to remove chlorine/chloramine from the replenishment tap water?

Until that tank is properly cycled, she needs to water changes at least weekly of 20-30 % and keep ammonia/nitrites under .25