Sump turnover too slow?

[Reefs and Geeks]

I know the rule of thumb for sump turn over rate has dropped in recent years, but just how slow is too slow?

I have a 150 gallon display, and have my return pump set to 100 gpm (measured with a 1 gallon container in the display and a stopwatch). So at just 2/3 of a turn over per hour, is there anything I'm missing out on by not having a higher turn over rate? I have no issues maintaining nitrate and phosphate at ultra low levels. I even started dosing nitrate recently. My tank water temp is at a stable 78F, water is clear, and protein skimmer has no problem pulling out dark skimmate.

I will be upgrading to a basement sump in the coming months as funds become available, and my sump will be almost the same size as my display. With that in mind, the cycle rate of the whole volume of system water going from the display to the sump and back again would be very slow, only a few times a day. Should I anticipate this causing any issues?

Are there any benefits to a low turnover rate? I know many return pumps have a feed mode, where flow is reduced for 15 minutes or so to allow time for fish or coral to consume food in the display, but I've never seen a need for this as my turnover is slow.

 

[ReeferMaddness843]

I run a little under 300gph on an 80 shallow with 40ish gal sump. I like the lower turnover for dwell time with skimmer which I think contributes to my ability to maintain no3 a little better as well. Or at least that’s what I tell myself.

 

[lpsouth1978]

...I have a 150 gallon display, and have my return pump set to 100 gpm ...

I assume you mean 100gph. At 100gpm, you are turning over the tank volume every 90 seconds.

I prefer a little bit higher turn over and generally try to match it with the turn over in my skimmer. If my skimmer is 250pgh, I try to match that in my sump as close as possible.

 

[mfinn]

The slowest I've ever heard was 3x the tank volume per hour, and what I shoot for is 4x to 6x.

 

[Reefs and Geeks]

I assume you mean 100gph. At 100gpm, you are turning over the tank volume every 90 seconds.

Yes, I meant 100gph. Used to typing gpm for work so much that gpm is just muscle memory.

Good point on the skimmer flowrate also. I can't seem to find the liquid flowrate of my skimmer (BM Curve 7) but it could be more than 100gph, so essentially could be acting more as a recirculating skimmer than single pass. Perhaps not a bad thing, or maybe it is. I guess it doesn't matter if I'm maintaining nutrients low enough to have to dose nitrates.

I guess if the return pump flowrate is able to maintain stable temp in the display and the filtration is doing it's job keeping nitrate, phosphate, akk, Ca...etc stable in the display than there's no issue. Perhaps the main negative is detritus won't be filtered through the sump and collected as efficiently, but if the water quality is good regardless, than maybe that doesn't matter so much. And more fish poop for coral to eat before being filtered out.

 

[EW_Fish]

This hobby has ton of opinions everyone does things differently and most of the time it works for the reefers. I run a 30b on a 120g I have my turn over set lower (i just added a seperate cryptic fuge) so I may bump the flow up since i can control that via another pump