Filter turn over rate

[Fishyyyy]

I currently have a 64 litre tank with a 600l/h all pound solutions filter. I am looking at upgrading my tank to a 120l and the filter company states that the filter is suitable up to 110l, however if I put my 600l/h filter into the 120l tank it will have a turn over rate of x5. Do you think my filter will be suitable for the new tank?

thank you

 

[AbbeysDad]

The interweb will tell you that you need 4x - 10x GPH flow rate relative to tank size. But good filtration is really about how well we filter the water, NOT how much or how fast we push water through media. There's a saying parroted about that "there's no such thing as too much filtration". This is usually interpreted as more powerful or additional filters. This is incorrect. You can typically do just fine with 2x -4x GPH flow rate relative to tank size.
Instead of more powerful filters, one should focus more on a filters surface area and composition for beneficial bacteria and microbes and not over service filters to negate their affect...although this becomes less significant in the established mature aquarium.
I hope this helps more than mud in the water.

 

[xxBarneyxx]

Short answer to the original question:

I think you will probably be fine as long as you have a good filter setup, good tank maintenance and don't over stock. Live plants will also be a massive bonus in taking some of the bio filtration load off the filter.

Long rambley answer discussing flow rates and filtration (feel free to skip).

I don't disagree with @AbbeysDad what they said is absolutely correct.

However @AbbeysDad you say:

NOT how much or how fast we push water through media.

Would how much of the water we are pushing through not have a massive impact on how effect the filter is?

You could have a bio filter the size of a house but if you are only running a 1/5th of the tank volume through it over the course of an hour you have a lot of water volume that hasn't been in contact with that filter?

Maybe its one of them things that what seems logical on the surface doesn't match up to reality. Maybe bio filtration happens so quickly that it doesn't matter how slow the water moves through it? I don't know.

In my mind at least the filter is created to be the best spot for the BB to live. As such I want the entire volume of my tank to be making contact with the BB as often as possible.

I always aim for 4 to 5 times tank volume in a well set up canister filter. Mostly because I know this has worked for me in the past. Too much flow through a filter is less likely to cause an issue than too little flow in my mind.

 

[AbbeysDad]

Maybe its one of them things that what seems logical on the surface doesn't match up to reality. Maybe bio filtration happens so quickly that it doesn't matter how slow the water moves through it? I don't know.

I believe that the efficiency of biological filtration is reduced at faster flow rates as the 'food' just blasts by. The race doesn't always go to the swiftest. I can also make the case that as flow is reduced, mechanical filtration gets better - I have seen this in our pool with the sand filter.

In my mind at least the filter is created to be the best spot for the BB to live. As such I want the entire volume of my tank to be making contact with the BB as often as possible.

In the early stages of a tanks eco-development, the filter is a great place for a beneficial bacteria colony. But as the tank becomes established and matures, all surfaces are home to beneficial biology colony(ies). The surface areas in the substrate far surpass the real estate in any filter and when undisturbed is home to countless beneficial microbes. Like soil, perhaps millions in a teaspoon.

I always aim for 4 to 5 times tank volume in a well set up canister filter. Mostly because I know this has worked for me in the past. Too much flow through a filter is less likely to cause an issue than too little flow in my mind.

Consider if you will the countless large fishrooms with only air driven sponge filters. The actual flow rates through these filters is nowhere near what we would see in many HOB's and most canister filters...and yet they work and work well.

Btw, I believe that one of the reasons under gravel filters somewhat failed and fell from favor is because hobbyists became convinced they needed fast flow through the gravel when in fact the opposite makes for better filtration.

Also, I once thought that filters should be kept clean to get the crud out of the system. These days all my filters, including the large HW 304-B canister filter on my 110g stock tank w/45g sump are filled completely with sponge material...and I let them run until the flow is very noticeably reduced. Much like the undisturbed substrate, biology establishes itself in in the filter media sponges, aiding water purity, and our meddling by cleaning merely disrupts the process. To some it may seem like neglect until you peel back the layers of understanding.

 

[Bruce Leyland-Jones]

You also need to be aware of the tank's fishey inhabitants. Some demand a relatively strong current, some don't.

 

[Colin_T]

Your filter should be fine if the tank is for normal freshwater fish.

You have a higher flow rate for marine tanks and Rift Lake cichlid tanks due to their high pH (around 7.6-9.0). Any ammonia produced in tanks with a high pH is extremely toxic and a filter turning the tank volume over 10 times an hour is better in this situation. However, if the pH is around 7.0 or below, then filtering the tank volume 4-5 times an hour is heaps.