Gettting the right filter for your tank

[Cliff]

I just read a reply to a comment I made that has me worried about my filter. I have a fluval 405 in my 55gal.

I've never really trusted the manufacture's recommedations completely so I've tried to go with how much water gets put through the filter. I always understood that in order for your filter to be effective, it has to filter the total volume of the water in your tank at least 4 times each hour. That would mean for a 55 gal tank you would need a filter that moves 220 gal of water through it each hour. As a fluval 405 have a output of 340 gal, it should be good for a 85 gal tank.

Am I undertanding this correctly ?

[VoidParadigm]

Sounds right to me.

[Scrup]

I just read a reply to a comment I made that has me worried about my filter. I have a fluval 405 in my 55gal.

I've never really trusted the manufacture's recommedations completely so I've tried to go with how much water gets put through the filter. I always understood that in order for your filter to be effective, it has to filter the total volume of the water in your tank at least 4 times each hour. That would mean for a 55 gal tank you would need a filter that moves 220 gal of water through it each hour. As a fluval 405 have a output of 340 gal, it should be good for a 85 gal tank.

Am I undertanding this correctly ?


Kind of.

It is a good rule to go by, but filter type and the filter media has a bit to do with it as well. More filter media would mean you could use a lower turnover, but its not something that is advised unless you really know what you are doing (more in the realm of custom filters)

the fluval should be fine for that tank.

Of course more never hurt anything, as long as its not a washing machine in your tank.

[Northernguy]

It depends on how your tank is stocked!
Cichlids have a high bio load.If I had an oscar and an pleco in that tank I would consider adding an aqua clear 110 to it with the fluval.
With smaller fish its not as big a problem but it still wouldn't hurt to have a secondary filter on every tank.
I would definately think about one with the stocking in your tank.

[Crispy]

I agree that any 75+ gallon tank should have more than one filter. That way, you can clean one at a time and not worry about losing your beneficial bacteria colony.

[190MPH]

I wouldn't buy into the 340 GPH on the 405, or manufacturer stated GPH on any filter for that matter. Chances are it's lower. As an example, and maybe one of the worst, I have a Cascade 1200 on one tank. It's advertised as 315 GPH. A quick check with a 1 gallon jug, and it took 30 seconds to fill. So 2 GPM x 60 minutes = 120 GPH. So having a secondary filter like an HOB on larger tanks, as I and others do, will provide the extra turnover and media capacity to be sure you are filtering enough. Of course alot depends on stocking too, as Northernguy mentioned, but extra is usually never a bad thing.

[Cliff]

To everyone who replied:

Thank-you very much for all the info, it's is really good. I have a aqua-clear that I'm going to add to the tank once I have the water lowered enough to move the tank away from the wall enough to put the filter on. I don't remember the size of the filter, it's the one that came with the tank.

Thank-you for your help

[SCcten]

I think that it is the gph flow rate without any media or carbon or filter sponges. I have 2 Rena xp3s and the flow rate on the front of the box is something like 350 gph but on the back in smaller print the flow rate with bio max, filter sponges and everything else is 184 gph. I assume the Fluva is the same. Hope that helps

[Cliff]

I think that it is the gph flow rate without any media or carbon or filter sponges. I have 2 Rena xp3s and the flow rate on the front of the box is something like 350 gph but on the back in smaller print the flow rate with bio max, filter sponges and everything else is 184 gph. I assume the Fluva is the same. Hope that helps

I've found the info that you are talking about. Now this makes even more sence to me now. There is two ratings in the manual that came with the filter. One is the flow rate which is 340 g/hr. Then there is a filter cirulation rate which is 225 g/hr. It looks like that is the measurement of water the filter puts out fully loaded with the filter material that comes with the filter.

Thanks for the info, it makes a lot more sense to me now.