How many times per hour do you want water turn over?

[tennisace]

I'm trying to decide what powerheads to get, so I asked the guy at the LFS and he said you want 5 turnovers per our (90g for me x 5= 450gph for all the powerheads to equal). This number seemed low to me, so I decided to come here (never listen to LFS). I want to have 2 powerheads for my eel tank, how many gph would you recommend?

 

[rivrat]

5 gallons is not nearly enough turnover. Depends on what you want to keep I would say you would want at least 20 to 30 times turn over and maybe more for sps. The main thing is not to have any dead spots in your tank where you have no flow at all.
rivrat

 

[hot883]

Originally Posted by rivrat
5 gallons is not nearly enough turnover. Depends on what you want to keep I would say you would want at least 20 to 30 times turn over and maybe more for sps. The main thing is not to have any dead spots in your tank where you have no flow at all.
rivrat
Right on the mark!

 

[tennisace]

I don't want corals, it is just for 2 eels. So what would you recommend if I have a 90g. Would you count the pipe that returns water from the fuge to the main tank as a powerhead, because my pump is 810gph.

 

[hot883]

Then just enough flow to ensure there are no dead spots. EELs create alot of bio load. You do NOT want dead spots in the water because their poop will strat to stack up in those areas. Ha!

 

[squidd]

My thoughts on Turnover/Suggested turnover rates...
FOWLR : (Fish Only with Live Rock) 10X to 15X Depending on species, some like Box fish/Cow fish need slower water or "some" protected areas, others like Tangs and most Aggressive do better (filtration wise) with more flow due to high waste load.
Reef, Softies only: 10X to 15X Good rate for filtration, but not too fast as some "branching" softies won't open fully if blown around too much...
Reef, Softie and LPS: 15X to 20X with "protected" areas for branching softies (see above)
Reef, LPS: 20X to 25X Excellent flow for filtration and keeping deitrus suspended and movement of micro flora and Fauna food supply as well as "waste" and slime removal from coral bedding areas...
Reef LPS and SPS: 20X to 30X More flow is beneficial to SPS, but some "protected areas" are needed for "pillowy" inflating LPS as they too do not appreciate being blown around.
Reef, SPS: 25X and up, 30X is good, more is better: Most SPS do well in high flow situations, with a combination of random and linear flow patterns (flow control, wave and surge action, mix it up) Benefit to filtration, deitrus suspension, Oxygenation, waste and aelopathy removal and micro flora and fauna feeding...
This is a "General" recommendation for "Total" turnover which is a combination of sump return and supplemental circulation devices "IN" the tank (power heads/closed loop etc...) and with any species there will be exceptions to the rule (some softies are OK in high flow, some SPS don't like getting blasted)
Much of your success and failure with these projected flow rates will come from Rock layout and flow Output direction...Due to varying Rock scape, tank size/shape, and circulation layout (rock/tank wall deflection, caves, competing/canceling effect of flow movement) You may find you need higher or lower "Pump numbers" to get the desired "flow effect" in your tank, sometimes a rearranging of rock scape or redirecting power heads is all it takes, sometimes you'll need to "UP" the pumping capacity...

 

[birdy]

Excellent post Squidd. :happyfish

 

[tennisace]

well that is good to know, thanks everyone and especially squid. Right now I have 810gph with my pump going from the sump to the main tank. 810 +540=1350 (1350 is x15 turnover, which is what I need at least). I think I will probably make it a little higher around 1400-1500 just to make sure because eel have such a high bio load, and later on I might want to be adding shrooms and stuff.