General Filtration Questions

littlegreentiger · Aug 26, 2011

At this stage it's no more than my curiosity that needs to be satisfied but I might take action depending on the answers I get. I have a 48l Fish Pod that came with an Interpet PF2 which suitable for 45-90 litres tanks according to the box it came in. Clearly that's perfectly adequate but I have read that you can't over-filter as such so is it case that more is better? Would a PF3 that is suitable for 82-133 litres be worth investing in at a cost of £25? Alternatively would an additional smaller PF1 suitable for 45-68 litres at just £12 be a worthwhile investment given what I perceive to be the advantage of creating more surface disturbance?

Also is it advantageous to add two foam inserts where there should be one or would you run the risk of over-working the motor trying to 'suck' through the two?

Finally, does a filter on a slow setting filter the water more efficiently because of the slower rate at which the water passes through and the lower force of the water meaning less chance of debris being 'forced' through without being filtered out because of the sheer force?

Sorry if these are spectacularly stupid questions or been covered before. As I said I'm just curious and don't have a problem with my tank. But if I can improve conditions for my little friends then I would certainly consider a change.

Cheers.

KittyKat · Aug 26, 2011

littlegreentiger said:
At this stage it's no more than my curiosity that needs to be satisfied but I might take action depending on the answers I get. I have a 48l Fish Pod that came with an Interpet PF2 which suitable for 45-90 litres tanks according to the box it came in. Clearly that's perfectly adequate but I have read that you can't over-filter as such so is it case that more is better? Would a PF3 that is suitable for 82-133 litres be worth investing in at a cost of £25? Alternatively would an additional smaller PF1 suitable for 45-68 litres at just £12 be a worthwhile investment given what I perceive to be the advantage of creating more surface disturbance?

While a larger filter will hold more media, which is good, it is also likely to have a higher flow rate, which may be unsuitable for the fish. So while I agree that more media is always better, I most definitely do not think that a higher flow is always better. Also, there is always the possibility that you have more than enough media for your fish as it is now. If I really wanted my filter to hold more media than your current filter, then I would look at small external filters.. but that's personal preference.

littlegreentiger said:
Also is it advantageous to add two foam inserts where there should be one or would you run the risk of over-working the motor trying to 'suck' through the two?

Two bits of foam is better than on in that you can then move one to a quarantine tank or donate to someone. It also gives bacteria double the area to colonise.. but as you say, it may cause your filter to break by putting unnecessary strain on the powerhead. It very much depends on individual filters for this one.

littlegreentiger said:
Finally, does a filter on a slow setting filter the water more efficiently because of the slower rate at which the water passes through and the lower force of the water meaning less chance of debris being 'forced' through without being filtered out because of the sheer force?

It shouldn't make much difference to the biological filtration, but having a faster flow will often stir up more #105###. I prefer to treat my filter purely as biological filtration, so I set the flow to what the fish prefer.

littlegreentiger · Aug 26, 2011

Wow thanks for the quick reply. I should have specified that this tank has Rummy's, Cardinals, a few Barbs and Khulis. The only ones that go close to the top of the tank are an odd Glowlight Danio and three Glowlight Rasbora (please forgive the common names - I don't know the scientific names) that are left over (and may be going back back to the LFS) from a batch that didn't seem to take too well to the move from the LFS to my home resulting in a significant number of loses

. (I'm on the look out for an alternative top dweller for future reference but I'll ask about that elsewhere)

I don't have any slow moving fish that don't like a high flow rate. I have the current filter going full bananas at the moment. A thought that crossed my mind was a second filter for extra filtration without running the risk of straining the motor on the current one with both turned down to their lowest setting could be an option.

Point taken about stirring up brown stuff in the tank on a high setting. I guess it's a bit of an individual trial and error situation rather than there being any hard-and-fast rules so-to-speak. I set it to max to disturb the surface as much as possible safe in the knowledge that I would be upsetting a Betta, for example.

I've never even looked at external filters to be honest. It's something I would keep in mind for future reference though.

As an aside this filter spits bubbles and I have one small and one large air stone in there as well.

KittyKat · Aug 26, 2011

littlegreentiger said:
Wow thanks for the quick reply. I should have specified that this tank has Rummy's, Cardinals, a few Barbs and Khulis. The only ones that go close to the top of the tank are an odd Glowlight Danio and three Glowlight Rasbora (please forgive the common names - I don't know the scientific names) that are left over (and may be going back back to the LFS) from a batch that didn't seem to take too well to the move from the LFS to my home resulting in a significant number of loses . (I'm on the look out for an alternative top dweller for future reference but I'll ask about that elsewhere)

Hemigrammus rhodostomus, Paracheirodon axelrodi, Pangio sp., Danio rerio and Trigonostigma hengeli or Trigonopoma pauciperforatum, as you expressed an interest..

Personally, I would be more worried about the stocking than filtration. Schooling fish school for a reason, so I prefer to keep them in groups of at least 6 and preferably 10-15+.

littlegreentiger · Aug 26, 2011

Cheers, much appreciated. That's satisfied my general curiosity.

Yes, although they appear happy enough at the moment I'm not 100% happy myself to be keeping just 1 Danio and 3 Rasbora together so have recently been considering donating them back to where they came from.

I do have more than 6 of each of the tetra. They rarely form a tight school. The Cardinal's in particular often split up into 2's and 3's and even hang with my Rummy's sometimes rather than their own kind.