Flow through sump

[captexas]

I am trying to finalize my tank setup as I am almost done building my sump for the 240g. As I have currently planned, I am looking at pushing around 1800-2000gph through the sump in order to feed two Sea Swirls, the refugium, and possibly some small canister filters. This is with estimating 650gph for each SS, 200gph for the fuge, and 250gph for the filters. The filters wouldn't be run all the time so I can boost flow into the fuge if needed. I'm looking at using a Sequence 3200 which would give me the flow needed.

Anyone think this is too much flow for a sump? And YES, I already have a closed loop planned with 8 other returns using a Sequence Stingray/Barracuda pump. The only other way I can reduce the flow through the sump is to use it only to feed the fuge and then setup a second closed loop for the SS. I'm just afraid that it would then be too stagnate in the sump. If I just reduce the flow to the SS, then they just become very expensive powerheads, but maybe that is ok.

I would appreciate any input as I'm having a hard time making up my mind! lol

[captexas]

DOH! Forgot that as the canister filters would dump back into the sump that it really doesn't count towards the flow through the sump, just the size of the pump needed. So, that puts me around 1500 to 1700gph. What do ya'll think?

[Henry]

I dont' think that is too much flow, but more importantly is the design of the sump. The first sump I built had plenty of flow going thru it but still had dead areas. Good luck.

[GaryP]

I think having stangnant areas has more to do with flow patterns then the flow rate. Corners, for example, are always going to be stagnant areas. I think that in a system like a sump there is also going to be channeling take place.

I'm not quite sure why you are concerned about stagnant areas in the sump. I have always thought low flow in a sump would be better. Why do you want to push several more times the volume of water through the sump then the skimmer and filters are capable of handling? Why not balance the flow of water with what is needed and put the emphais on flow with the closed loop whose primary purpose is flow?

[captexas]

I'm not so much concerned with stagnant areas in the sump, just meant it more of turning the sump into a simple water storage tank with such a low flow. The flow rate/turnover to the skimmer is controlled by the pump feeding the skimmer, not how much water flows through the sump. On the closed loop, I can only push so much water through a pipe and through a OM 4-way. I was hoping to utilized the built in overflows/returns of the reef-ready tank for the sump drain/return. If I can get that much flow through those drains, why not use it? I dont' know, the more I think about how to set up this tank, the more confused I get! lol :wacko

[don-n-sa]

IMO I like to have as much flow as possible without micro-bubbles and splashing noises.

If you have a very large sump like I have on my 240 then you can get away with a lot of flow. My sump is 64 x 16 x 16

[NaCl_H2O]

I agree w/Joshua - too much flow. Didn't see the size of the sump above, but that obviously factors in. In general, 5x or less of your tank volume is a good target to push through your returns - so that's probably 800 - 1000gph depending on your tank's actual water volume.

The sump is where most of the gas exchange occurs, and the longer the water is in the sump, the more your skimmer can work on it.

Sounds like you have several other pumps in/out of the sump for the skimmer, canister filters, etc. If the in/out for these are from different chambers (across baffles/dams) then you will be increasing the flow across the baffles. This can result in more turbulence in the sump and trap microbubbles that will get returned to the tank :angry

I have a 700g capacity system (probably 500g operational) with a 160g sump (probably 100g working volume) and I have a nice calm 1500gph flowing through the sump. In/out to other equipment (such as the skimmer) are as early as possible in the flow direction ("dirtier" water), and as far as possible from the return pump - time for bubbles to escape to the surface.

This is one of the design details that most folks don't spend much time on - bulkeads, pumps, etc. are connected where they fit or where it is easiest. Take some time designing our "filtration system" - it IS the most important aspect of a successful tank!

[captexas]

Steve - yeah, I'm slowly going nuts trying to figure out how to plumb my system, thinking about it too much!


OK everyone, another question for you. How much water are you pushing through your refugiums? I was guestimating going with around 200gph. The fuge will be 20in wide by 20in. long by 30in. high. To get even flow through the fuge I was thinking of using a vertical spray bar, but that would have to either have a quality check valve on it or be on a closed loop feed as it will sit up next to the stand. I'm thinking putting it on a closed loop feed would make it easier to add or reduce flow if needed as well without affecting other things too much. Just curious about the gph most people go with. I wish flowmeters were cheaper and easier to use, I'd love to see what my actual flow is on my current tank.

[GaryP]

Chris,

200 gph sounds good to me. I have no way to measure my flow in my fuge, but its probably in that neighborhood or a little less. I just have a valved T off of my return line going to the fuge. The valve is just barely cracked open.