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View Full Version : Managing flow HELP (several questions)


Abominable Reefer
03/18/2004, 02:25 PM
Please tell me if this makes sense for a reef ready set up:

I figure it's better for your drains to outstrip your return pump, because if your sump is large enough, it will never overflow (given your standpipes are designed to match your sump size). So therefore, if you are going to regulate flow with valves, you should do so on the drain pipes. I would think this would also make the pump last longer. I'm a little nervous about adjusting valves on the drain lines, because it seems like it would make it more likely that they would clog up, which would overflow the tank. Any thoughts?

With my pump (MAG 18) and my estimated head pressure, I anticipate getting about 1121 gph of flow. Putting this into the drain size/overflow calc, I got a drain pipe size of 1.38 and a linear overflow size of 17" Rounding up, I would need a 1.5 drain line right? And if I want two drains, I would go to 2 x 1.25" right? So if I give myself a couple extra inches of linear overflow, and 2x1.25" standpipes, I'm guessing I'll be OK *gulp*

Finally, I'm putting this together for a 100 gallon tank. I think I'll be able to fit a 20 or 30 gallon sump under the stand. Assuming I get the 1121 gph above, can I make up the extra 100 or so gph I need with a closed loop? Or are the flow recommendations for flow through your filtration system only?

I think I'm close to being able to put this baby together, just want a little reassurance and feedback from the pros.

irishpete
03/18/2004, 03:37 PM
First of all, thats a lot of flow! I have a Mag7 puishing about 450gph w/ head. I used 1/2" pvc for pump and have a dual overflow box rated at 1000gph. So I cap-ed one of the overflow drains and ran a 1" return to my sump. I added ball valves at both input and output. I only use the valve for my pump when I need to service my sump and I use my drain valve to adjust for noise reasons only. I think that dual 1" drains would be more then sufficent for your application, but if you do go with one return then yes, I would make it larger because there is minimal pressure on your drain and your return is pressurized so it can use a smaller pipe.

and the drain shouldnt get clogged if you use a pre-filter on your overflow, and I would monitor it for a little while, but all in all I dont worry about mine, it is steady and quiet and I also added a UPS (battery backup) for my pump, in-case the power goes out.

hope this helps. just what I did and personal experience.

Abominable Reefer
03/18/2004, 04:56 PM
Thanks for sharing irishpete. I guess it is a lot of flow (~10x). I've seen people here with much more though.

Any other comments or advice is welcome.

Matt

DougSupreme
03/18/2004, 05:37 PM
are you using a overflow box? if so, there is no need to "match" the output of your drains to the capacity of your pump. Leave the drains wide open and let the pump run full strength. With an overflow box, the drains will only receive as much water as the return pump can supply. It sounds like you are using a standpipe of some type to maintain your water level in the show tank. If you want to remove the standpipe from the tank, and make it external, do a search on Garner Standpipes. Here are some pics of my external standpipes.http://reefcentral.com/gallery/showphoto.php?photo=30052&papass=&sort=1&thecat=500

Abominable Reefer
03/18/2004, 06:43 PM
Hey an epiphany. You're totally right. An amazingly simple concept now that I think about it that way. The water level in the overflow only rises as fast as pump can supply it. So as long as I have an adequate number of standpipes of a given size, the water level will stay constant. Thanks!

DougSupreme
03/18/2004, 08:10 PM
By Jove, I think he's got it!

Glad I could help

DougSupreme
03/18/2004, 08:26 PM
just trying to see if I can get my pics to show up in a post

AZDesertRat
03/18/2004, 08:40 PM
I have a LeeMar 100G with a center internal overflow and the modified 1" Stockman standpipe. My sump is a 30G long with a small refugium on one end, skimmer and heater in the center section and return pump on the opposite end. The return pump is a OceanRunner 3500 returning close to 800 GPM thru 2 ea. 3/4" Locline returns. I also have 3ea. 1" bulkheads through the back for a closed loop which uses a QuietOne 4000 pump pulling from about 12" down and almost back center, through a SCWD and out 3/4" Loclines in each upper back corner. This is also pushing about 800 GPH and switches sides about every 8 or 9 seconds.
All that said, I think I am actually borderline on flow if I wanted to have more SPS or high current corals. I really didn't want to but I think I am going to add a MaxiJet 900 in the back behind the rock work to increase flow a little.

Abominable Reefer
03/19/2004, 02:33 AM
Yep, sounds like with 1200-1300 gph hour through my sump and closed loop, I will have to be careful what corals I buy. Since this is my first reef, I'm planning to go pretty conservative while I'm still learning what I'm doing.