I'm curious about the turnover ratio other members have for their tanks. I use the the Eheim Pro III for one of my 47G, rated at max T/O rate of 450GPH. I'm replacing that tank with a 90G, using the same filter. That would give this tank a T/O of (hopefully filter pumps correctly) of 5 times per hour. I know recommendation is 6 times per hour. Planted tanks don't require as much, though. I'm curious how other members filter their tanks
FIltration Turnover rate
- Thread starter ricoishere
- Start date
Using Turnover rates to gauge filtration is simply a general guide that we can give to inexperienced fish keepers to put them on track… but there are much more detailed ways of planning your filtration as you gain experience at which time these general guides should be ignored…
For healthy bio filtration you need to ensure there are no dead spots… That’s about it…
It is commonly believed that ample bio media is needed to supply space for bacteria to cultivate. I’ve personally kept many tanks and do not use any bio media and have never once had a mature tank suffer from not having enough surface area to supply a bacteria colony… but that’s a different debate… so in addition to preventing dead spots in the water you may want to use some bio media to host bacteria…
For healthy mechanical filtration, you need enough current to carry the waste to the filter intakes. Small fish have small waste and this can be achieved with smaller turnover rates. Big fish have big waste and it therefore requires stronger currents to carry their waste to the intakes. This obviously shows that no “rule of thumb” can cover all situations.
Once the waste is pulled into the filter you will want to have media set up in such a way that the physical waste is pulled out of the water and doesn’t simply get pushed back into the tank. When waste is pushed back into the tank this is referred to as “bypass”, meaning the waste bypassed the media.
How much décor you have and how the décor is set up will greatly impact the amount of flow is actually taking place in the tank. An empty tank with “6 times turnover” will be experiencing much more movement in the water column than a tank with the same turnover that is densely stocked with rocks, wood, etc.
For healthy bio filtration you need to ensure there are no dead spots… That’s about it…
It is commonly believed that ample bio media is needed to supply space for bacteria to cultivate. I’ve personally kept many tanks and do not use any bio media and have never once had a mature tank suffer from not having enough surface area to supply a bacteria colony… but that’s a different debate… so in addition to preventing dead spots in the water you may want to use some bio media to host bacteria…
For healthy mechanical filtration, you need enough current to carry the waste to the filter intakes. Small fish have small waste and this can be achieved with smaller turnover rates. Big fish have big waste and it therefore requires stronger currents to carry their waste to the intakes. This obviously shows that no “rule of thumb” can cover all situations.
Once the waste is pulled into the filter you will want to have media set up in such a way that the physical waste is pulled out of the water and doesn’t simply get pushed back into the tank. When waste is pushed back into the tank this is referred to as “bypass”, meaning the waste bypassed the media.
How much décor you have and how the décor is set up will greatly impact the amount of flow is actually taking place in the tank. An empty tank with “6 times turnover” will be experiencing much more movement in the water column than a tank with the same turnover that is densely stocked with rocks, wood, etc.
SuperDave;3328426; said:
Very true... In my experience it is safe to assume a canister will actually move about 50~60% of what it's motor's maximum flow rate is measured at...
ALL pretty good and true comments. I'm considering getting another eheim 2028. I have 2 already on 2 other tanks, and this way I can keep the media, pads, and all accesories the same (can't help it, I'm a logistician). So this planted 90G will have the Eheim Pro III,a 2028, UV, compressed CO2, and a powerhead on timer for the rainbows to play in.
nc_nutcase;3328224; said:
"For healthy bio filtration you need to ensure there are no dead spots Thats about it "
How do you accomplish this ? How is it measured?
Isn't it generally accepted for a light to moderatley stocked . lightly fed, freshwater aquarium that a turnover ratio of 4x per hour is accepted? taking into into account the diminished GPH as the filter media becomes plugged?
Beneficial Bacteria can/will grow on any/all surfaces... provided there is water movement, thus no dead spots, the water will come in contact with a bacteria covered surface in a very short time thus accomplishing bio filtration...
It is measured by monitoring ammonia/nitrite/nitrate...
As I described in quite a bit of detail in the post you quoted... there are many factors that heavily impact the result of filtration therefore judging or rating ones filtration on "turnover" alone is inadequate. Suggesting a turnover of X times per hour is what we should be suggesting to people not willing to think things through. As the OP here seems to be trying to think things through, I offered some ideas of things to think about that will directly impact his filtration.
It is measured by monitoring ammonia/nitrite/nitrate...
As I described in quite a bit of detail in the post you quoted... there are many factors that heavily impact the result of filtration therefore judging or rating ones filtration on "turnover" alone is inadequate. Suggesting a turnover of X times per hour is what we should be suggesting to people not willing to think things through. As the OP here seems to be trying to think things through, I offered some ideas of things to think about that will directly impact his filtration.
I have a Fluval 404 rated at 340GPH and 2 AC 110 rated 500GPH each, on a 70 Gal Bow. So i'm looking at 19 turnovers in a Hour based on what the manufactures rate at, but we all know its less...