Filter Flow Rates

[stiffler69]

Here we go so im running a total of 4 tanks all fairly small.

Now my first tank is a aquastart 320 28 litre and has a under gravel filte. Water is always crystal clear and gravel is always clean and the flow rate has never changed from day 1 its always had a good strong flow.

Second tank is a 54 litre fry raising tank and has a large vita tech 300 lh sponge filter, the last few days ive noticed that the water has started to slightly cload the filter was gagged a little and not flowing at full rate, so i cleaned it using old tank water and now is flow good again

Third tank another 54 litre brittle nose plec breeding tank, now this has been running for months with guppies and plattys in only just transfered it for the plecs, This has a large fluval 300 lh sponge filter in, and also becomes slow on the flow rate and gagged up and needs regular cleaning

My 4 thanks is a 40 litre goldfish tank and runs a fluval 150 lh filter and this also becomes gagged and gets a slow flow rate and sometimes becomes slightly cloudy

Now my question is what filters do you think are the best cause my expereince tells me that the under gravel filter is the most effeicent at its job and requires the least maintenance is this true and should i look into this type of filter for my other tanks

Thanks in advance

 

[backtotropical]

Hi,

Under-gravel filters do have their good points as you have already pointed out. However, they also have their down-sides as do all filters. They don't tend to be used very much in the hobby these days other than in LFS shops because they are cheap and easy to maintain.

The under-gravel filter works by pulling water through the substrate, where the water is filtered, using the substrate as a mechanical and biological media at the same time. The problems arise when regular gravel vaccuming is not maintained and the gravel starts to trap a load of detritus and can get clogged. As a result, the filter's performance is reduced.

'Dead spots' can also form where the flow through certain areas of the substrate (usually furthest away from the outlet) is reduced or eliminated due to a build up of waste in the gravel.

These filters are also not the best choice for a planted tank as the plants don't like the circulation of the water around the roots.

Large boisterous fish will dig and rake the gravel often to the extent of rendering the UGF useless as the media is not allowed to do its job.

That said, they can be very useful filters as you have pointed out, and if plants and boisterous fish are avoided, and regular gravel vacing is maintained, UGFs will do a good job.

I personally won't look past external canister filters for their filtering capacity and efficiency. Maintenance is also relatively easy, depending on the model. Of course, these are not faultless either as the fast flow rate for instance is detrimental to some fish. Each tank has its own individual requirements and several different filters, not limited to the ones i have mentioned, still have a place in the hobby.

BTT