How to determine turnover rate ???

[gio28]

Originally Posted by DarrinSimon
http:///forum/post/3107880
Hello Gio28 I hope you don't mind if I jump in here, I am planning on incorporating a sump in the near future. I found a great article here http://www.melevsreef.com/allmysumps.html
Vince's quote above (that part of it anyway) has me confused. Is he saying the DT should drain water faster than the sump returns it? Wouldn't the sump overflow if the DT is draining it faster than the sump could return it? I thought you wanted the draining to pretty much match the return? No?
I am such a sump noob. Vince? Help I am drowning in my sump plans!

yeah the DT overflow needs to be greater than the return pump. its really hard to understand but to make it simple...the overflow and return will balance out and neither will overflow.
flooding can happen in 3 ways (from what i understand):
-power outage means water flows into sump making it overflow
to fix: simulate a power outage and make sure your sump has room to accommodate the excess water that comes from the overflow.
-reverse siphon from return pipe
to fix: drill a hole (or two) in the return pipe right under the water level in the DT. that will break a possible reverse siphon
-overflow looses siphon
this will never happen as long as the U-tube is submerged in water and there is no bubble build up in it.
hope this helps. its really confusing sometimes...it took me a while to fully understand.

 

[darrinsimon]

Okay thanks Gio28! Yes my brain is hurting from all the reading, it can get confusing.
I know they say you don't want too much flow through your sump, it causes micro bubbles. 3 to 5 times the volume of your tank is what I read from Melevsreef. I guess you don't want too great of a difference in your overflow vs. drain rate, or does it matter? I read that as long as your overflow runs at 70% of it's capacity you should not get the bubble buildup in the U tube.

 

[zman1]

Originally Posted by Bang Guy
http:///forum/post/3107930
As long as there's a trickle of flow it will be enough to cool a hobby sized pump. But then, who would restrict their flow that much?
Most external only pumps are fan cooled motors (running these dry damage the seals). Submersible are water flow and surrounding water cooled. The MAg drive claim both external/internal. I have a few of those, I wouldn't run them external. However, I get ALL of the heat transfer in the system water. I use one in my mixing tank and it does a fine job at bringing up the temp overnight...

 

[vince-1961]

Okay folks, a lot of ya'll can't see the forest because you're looking at the trees. So, water flow 101:
First and foremost, the water from your sump gets to your DT via your pump. The water from your DT gets to your sump via your drains. Your drains must have more capacity to move water than your pump. If not, your DT will over flow, b/c the pump is putting more water into the DT than is draining out of it via your drains. Drains are powered by gravity. Pumps are powered by electricity. If you pump lines are 1" and your drains lines are 1.5" diameter, both of which are fairly standard, then stop thinking about it. It's cool.
Secondly, your sump pump moves water at the rate of X gallons per hour. (Per above, as long as your drains are greater than X, your DT will not overflow.) If the sump pump is the one and only thing that moves water in your DT, then it should be able to move 10 to 20 times the gallon capacity of your DT. (The 10 to 20 times gallonage of tank is called "turnover", meaning the number of times that the water in the the DT is turned over.) For most of us, it is unrealistic to expect our sump pump to push enough gallons per hour so that GPH = 10 to 20 times the gallon capacity of the DT. Therefore, most of us add water fans to the inside of the DT. They're called "powerheads." Alternatively or additonally, you add a closed loop, but that's more $, more work and more complicated.
Thirdly, the rate at which water flows through the sump is equal to the rate at which your sump pump pushes water into the DT. "Equal" means no more and no less. (DUH!) Compared to the turnover of your DT, the rate at which water flows through your sump is irrelevant. In other words, stop thinking about the rate at which water flows through your sump. It's just simply not important, unless of course, your pump is way too strong for your set up.
DarrinSimon, whatever you read on Melev'sReef was either wrong or specialized to the particular set up. The sump cannot overflow when the pump is turned on, because the volume of water entering the sump is equal to the volume of water being withdrawn therefrom and moved to the DT. It cannot be otherwise, unless you restrict the flow of water in the drains to a capacity less than the ability of the pump to put water into the DT, in which case the DT overflows, or unless you add a second pump to pump water out of the DT into the sump, in which case the sump overflows.
That article on Melevsreef says "The sump's return flow would be a portion of that total circulation, maybe 3 to 5 times the total circulation, and the rest is provided with powerheads and/or a closed loop system." The quoted statement may be the source of your confusion, because it is poorly written. Powerheads add turnover to your DT, per my statement above, but do not involve your sump pump or your sump, b/c powerheads are located within the DT. In the quoted sentence from melevsreef, "total circulation" is what I called "turnover."
I'm tired of typing now.

 

[darrinsimon]

Thanks for all that typing vince-1961, it's making more sense now. Wow, look at the forest!!!

 

[bms]

Vince-1961: i think some of the people here are getting confused between FLOW RATE and TURNOVER RATE. Both of which are important and both of which vary. If I understand correctly, the flow rate (which should be 4x or more) is the amount of water flowing through your sump/filter(s). Turnover is the amount of water being turned over or "moved" in your tank (which should be 10x-30x). This includes pumps, filter, powerheads, etc..pretty much everything except your skimmer?