Filter size

[stevo1957]

I have a tank of around 120 - 130 ltrs (70cm x 40 cm x 43 cm) which has an Eheim 2215 that I have had for a number of years.

Of late, I think filter is struggling (despite changing the impeller recently) as the tank gets dirty a lot quicker thatn it used to and when i clean the filter, media and spnges aren't all that dirty. It is rattling a bit lately and is hard to prime. I'm finding I have to shake it every few days to keep quietening it down.

So I'm thinking it's time for anew filter.

From my research, I'm leaning towards Fluval  but would obviously appreciate any other brand recommendations to consider.

I'm trying to size the filter, but get differing recommended requirements re flow rates. eg 5 times, 6 - 8 times or 10 times tank capacity. 

According to specs, my size tank is matched to:

- a Fluval 207 which suits tanks 60 - 220 ltrs with max flow 780 ltrs per hour
- a Fluval 307 which suits tanks 90 - 330 ltrs with max flow 1150 ltrs per hour.

I'm reading that "bigger is better".

The Fluval 407 is recommended for tanks 150 - 500 ltrs with max flow 1450 ltrs per hour.

My current Eheim 2215 series is only 620 ltrs per hour.

When is a filter too big? Would the 407 create too much current from the return line?

Of these 3 sizes, which do you recommend? 

I'm thinking the 307 would be the one as if flow is too high, it can be adjusted down, and it is a good improvement on the flow rate of my current Eheim.
The 407, I think, would be far too much flow, for my size tank, even after adjustment.

[MattG_Sydney]

Hey Steve, I am no expert on the subject. Based on what you said, I would go with the 307 (I have 306,207,407 and the FX4). I am running a 307 in my  2 x 2 x 2 tank. No issue at all. I have a sponge filter as a back up + plenty of media in the filter and in the tank(marine pure). (Breeding tank). 
As a side note, I would clean the pipes and see if there are any gunk in them as that can happen after years of use.
You can look at Seachem Tidal Power Filter 110 as well. I have one and I am happy with the performance. However I feel 307 would be much superior for a display tank as it it a neat unit.

 

 

All the best. 

Edited November 30, 2022 by MattG_Sydney

[Jason]

Hi @stevo1957,

As a general rule of thumb, I always try and size any canister filter having a flow rate of around 4 to 5 times the tank volume.   In this instance the 207 would be a work, however I'd agree with @MattG_Sydney and go the 307.    For the slight extra cost you are getting a much bigger filter volume (7.3L compared to 5.3L).   A 307 on that size tank could go months without needing a clean.

Cheers,
Jason 

[Skippy]

I have a Fluval 405 on a 2 foot cube (60 x 60 x 60cm) approx 216 litres.  The flow from the outlet is very strong, I think a 407 would be overkill on a tank your size.

I believe that the way Eheim rate the flow of their cannister filters is different to other manufacturers.  Some manufacturers test flow rates with an empty cannister.  

Ultimately it depends on what you want to use the filter for, if it's purely for mechanical filtration a higher flow rate is more important.  If you want to use it for biological filtration too then the amount of time that bacteria is in contact with waste is important and a higher flow rate might not be optimal.

 

[Link2Hell]

@skippy mate that is exactly correct re the flow rate of Eheim to other filters

I run 2217 on my 2ft cubes and most of my filters are Eheim as I like to go 

the next size up from what is rated and I also look at the bio load plus what fish 

type are in the tank as some prefer more current

having said that I also have other makes but as far as longevity the Eheims 

seem to out last them all but have had good results with SunSun and Aqua One

never liked the flexi hoses on the Fluvals maybe they are different now 

re the rattle it could be the ceramic shaft is worn if that wasn't replace with

the impeller or the shimming is insuffcient at the top of the shaft and has too

much free play on the impeller movement and it is rising to far in the housing