turnover rates

[esoxlucius]

It seems to be the norm in the hobby nowadays that a turnover rate of anywhere between 5-10x your tank volume per hour is where every hobbyist should be aiming for. I can fully understand this on a marine set up where the hobbyist needs to replicate reef conditions. But freshwater? Are huge turnover rates really necessary? If you're keeping species that originate from fast flowing well oxygenated rivers then i can understand big turnover rates but what about stillwater species? Should it still be the norm to run at high turnover rates with stillwater species or can these high rates be dialled back, and if so what's the bare minimum you should be aiming for?

 

[jwh]

I run mine at between 2x and 4x turnover without problems, you need to take into consideration things like stocking levels, bio load generated, amount of bio filtration, plants etc. The rule of thumb must be your water parameters, if they are good, your filtration works.

 

[pacu mom]

Generally, it depends on the type of filtration. The turnover rates I've heard touted on different fish forums is around 4X or less for biological and chemical filtration and 10X for mechanical filtration. The turnover rate for a UV sterilizer is very low, in fact, if you increase the flow rate, you have to increase the wattage for it to be effective. Most people use a combination of mechanical and biological like a sump or canister, so the turnover rate will be somewhere between 4X and 10X. Good water parameters and water clarity tell us we've achieved our goal. Anything we add in addition is just fluff. Some of us just happen to love fluff. We do it because we can.

 

[Drstrangelove]

Other people (and I) have run FW tanks with low turnover rates. A lot of variables come in to play such as amount of protein that goes into the tank, amount of biological media, amount of alternate methods of removing nitrogen, sensitivity of the stock, etc.

As JWH and Pacu Mom have said, if your parameters are good, you likely have the right amount. OTOH if your parameters are not good, increasing turnover might work or it might not solve the problem.

People under ideal conditions have kept tanks with turnover levels of 1-2 or less, so there is no magic number that works for all.