anyone have an answer?

[KevK]

IMO The 10X flow is starting to sound like "watts per gallon" to me. Blasting water between the tank and the sump just to get to 10x flow doesn't make sense. Good random flow sounds better, regaurdless of the source. I currently run a big pump with multiple scwds and returns, but a smaller pump on a closed loop with less head pressure, would generate more flow with less heat and use less electricity.
If the return to the sump is to skim, add calcium(Kalk/reactor), heat or cool,and filter 10x sounds very high to me. The water does not need to be charcol filtered every 6 mins.

 

[Scuba_Dave]

I wasa going to use the watts per gallon example. Maybe they are all guessing. What is a true test? As you add fish, you need more skimming. If you have 1 fish in a 125g a lower sized skimmer whoudl work fine. Now toss 15 fish in, & suddenly your skimmer is undersized.
I think there are too many variables to come up with an exact number "x" turnover & you won't have a problem. Rock placement, Powerhead placement, type of powerhead/pump, type fo drain, how many fish, cleanup crew, skimmer size, placement...plus more
I think experience is the best measure...

 

[Matt L.]

Scott,

I wouldn't give up completely, although I understand your frustration. I think the confounding factor here is that a computer model is really required to answer your question on tank HRT. I have spent some time thinking about it since you initially posted, and the series of equations (along with their innumerable assumptions) needed to model skimmer performance on a reef tank with summp is way beyond our ability.

I do believe the main tank HRT matters. If you have a 100gal tank and a main pump with a flow rate of 1gph and a 1500gph skimmer in the sump, that clearly won't do, as the nutrient input to the tank can't be processed by the skimmer in the sump fast enough. Conversely, if you have a 100gal tank and a mian pump with a flow rate of 10,000gph and a 1500gph skimmer in the sump, then that is also unnecessary, as a flow rate that fast turns the tank water over at a rate far greater than the skimmer would need to keep up with the bioload in the tank. Where does the optimal condition lie? Sorry, I don't have an answer for you there,

Matt

 

[Matt L.]

Matt, you're a S.A. (no, not secular authority) :-D
I meant 10 times per HOUR thank you.

I wasn't doing it on purpose -- I was seriously confused by what you meant.

Matt

P.S.: Now to be a S.A., you would want to write it 10/hr (not 10*hr).

 

[ScottM]

I wasa going to use the watts per gallon example. Maybe they are all guessing. What is a true test? As you add fish, you need more skimming. If you have 1 fish in a 125g a lower sized skimmer whoudl work fine. Now toss 15 fish in, & suddenly your skimmer is undersized.

again this i a skimmer size selection question. i would like to think that a you upgrade your skimmer you would upgrade your return pump

I think there are too many variables to come up with an exact number "x" turnover & you won't have a problem. Rock placement, Powerhead placement, type of powerhead/pump, type fo drain, how many fish, cleanup crew, skimmer size, placement...plus more
I think experience is the best measure...

i think all of these varriables are related to the INTERNAL tank flow and skimmer size rather than water delivery to the skimmer.

 

[Greg Hiller]

IMO the water movement within the tank is the main consideration. I don't think you need that much flow from sump to tank. The extreme situation would become if you had a REALLY low turnover rate, then the calcium and alkalinity (and temperature, etc.) could become become depleted in your tank because the calcium reactor is in your sump. Another consideration is the build up of gulk on the surface of the water. A decent turn over rate helps to minimize this, but I've also learned that the 'distance' the water falls in going over an overflow can also influence this.