Hi all. What is the desired turnover rate to achieve best water quality for a tank ? And what is the minimum turnover rate, be it big or small tank. I plan on keeping some slow flow, air breathing fish, and also some fish that require strong flow/current. I have a 900 liters tank which I plan on keeping slow water moving fish and air breathers, and a 80 gallon for some barbs and other fish that require some flow. Thanks you
Tank minimum flow turnover ?
- Thread starter Barca
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I've always gone 4 - 6 in freshwater and 8 - 10 with marine. Others will say higher some will probably say less is ok which does depended on the setup and how much stock you have in the tank. I've been fish keeping for over 30 years and have always gone more than I need. I find going that bit higher polishes up the water very nicely too. At the moment I have my Oscar tank turning over just over 6 times per hour and the water parameters and clarity are spot on.
When you go with a turnover rate of 4 times which filtration setup may I ask ? like a canister or sump ? Thank you
With hang-on-back filters I strive for close to 10x turnover per hour. For example, my 90 gallon tank has a filter pumping 500 gallons an hour and another one 300 gallons an hour. So 800/90 is about 9x. Much would depend upon size of fish, quantity of each, amount of feeding, frequency of water changes.
In tanks over 30 gallons, I prefer to have two smaller filters in a tank as opposed to one big one of the same volume, in case one dies for whatever the reason.
If you are using canisters or sumps, the 10x rule might not exactly apply.
In tanks over 30 gallons, I prefer to have two smaller filters in a tank as opposed to one big one of the same volume, in case one dies for whatever the reason.
If you are using canisters or sumps, the 10x rule might not exactly apply.
I use a canister but Id apply the same if I were using a sump. I've only ever used sumps when keeping marine and then would go for over 10x turn over. For a normally stocked freshwater tank x5 times is a nice balance and its not too turbulent inside the tank. If you are heavily to overstocked then you should be pushing for x10 but I'm not a fan of heavily / overstocked setups. This has always worked spot on for me with zero issues and the water always looks crystal clear but this is also down to a good maintenance schedule.
Turnover rate has to do with making sure all the water in the tank flows thru the biomedia enough times to remove ammonia, so that ammonia doesn't build up, and poison the fish.
Although flow rate and turnover are related, they are not exactly the same.
Fish like darters, trout, and the cichlid genera like Rheophillus and Tomocichla and some Geophaines, require high flow rates, and high oxygen content.
They have evolved to live in higher flow environments.
The flow rate they require can be achieved by adding powerheads that create that rapid flow, highly oxygenated environment, without increasing turnover rate.
As long as the turnover rate is sufficient to remove ammonia you are OK.
Air breathers like many Anabantids, and Bichirs that come from swamps, or more stagnant areas"usually" don't require the type flow rates powerheads provide, they come from more placid environments in nature.
But a turnover rate enough to remove ammonia is still desired. In nature the thick surrounding vegetation serves to remove nutrients in those areas.
Type of filtration is not important (cans, HOB, sumps) as long as it is sufficient to do the job for the stocking and size of tank, and the filters are cleaned enough to not allow them to become nitrate factories themselves..
Nitrate removal is another matter, because it is not removed by filtration, it is most efficiently removed by water changes.
Some "Air breathers" may have a higher tolerance for nitrate than rheophilles.
I use a 125 gal sump on my 180 gal tank, with a 1200 gph pump (turnover rate of 5 Xs), but because my fish are riverine, I add powerheads to simulate that stronger constant flow environment, and do 30-40% every other day water changes to simulate the undetectable nitrate levels in their natural environment.
Although flow rate and turnover are related, they are not exactly the same.
Fish like darters, trout, and the cichlid genera like Rheophillus and Tomocichla and some Geophaines, require high flow rates, and high oxygen content.
They have evolved to live in higher flow environments.
The flow rate they require can be achieved by adding powerheads that create that rapid flow, highly oxygenated environment, without increasing turnover rate.
As long as the turnover rate is sufficient to remove ammonia you are OK.
Air breathers like many Anabantids, and Bichirs that come from swamps, or more stagnant areas"usually" don't require the type flow rates powerheads provide, they come from more placid environments in nature.
But a turnover rate enough to remove ammonia is still desired. In nature the thick surrounding vegetation serves to remove nutrients in those areas.
Type of filtration is not important (cans, HOB, sumps) as long as it is sufficient to do the job for the stocking and size of tank, and the filters are cleaned enough to not allow them to become nitrate factories themselves..
Nitrate removal is another matter, because it is not removed by filtration, it is most efficiently removed by water changes.
Some "Air breathers" may have a higher tolerance for nitrate than rheophilles.
I use a 125 gal sump on my 180 gal tank, with a 1200 gph pump (turnover rate of 5 Xs), but because my fish are riverine, I add powerheads to simulate that stronger constant flow environment, and do 30-40% every other day water changes to simulate the undetectable nitrate levels in their natural environment.
