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Goodwin9
04/15/2007, 05:35 AM
I am wondering if anyone can help me figure out my return flow problem I am having.

I have been running my 470 tank with a Blue Line 100 drawing from the sump, running through 3 Life Guard canister filters, then through a chiller back up to the tank in a 1" line that splits at the top of the tank to the 4 returns in the tank.

Yesterday, I added a Blue Line 70 pump drawing from the sump, and ran it through the chiller then back up to the tank, where I split the returns so that 2 were from the BL 70 & 2 were from the BL 100. I cut the chiller out of the BL 100 loop so that it was just going through the canisters before returning to the tank.

I did this for two reasons, to increase the flow to the tank, and to have a second pump feeding the tank incase the original BL 100 failed. (This was the only pump feeding the tank).

The problem I now face is the erratic return flow I am getting back to the sump. There are two 1 1/2" return lines from the tank into the sump. There is what I would call a "surge" in the return flow coming into the sump. I had hoped to use one of these return lines to feed the new skimmer I am planning on installing. I don't think that this type of return flow would work for the new skimmer.

Here is a video of the two 1 1/2" return lines entering the sump.

http://i102.photobucket.com/albums/m95/goodwin9/470%20Return/th_100_2146.jpg (http://s102.photobucket.com/albums/m95/goodwin9/470%20Return/?action=view&current=100_2146.flv)

Can anyone offer any suggestions on why this happening, or how I can correct it to stop this type of flow. If I shut off either one of the pumps, the flow seems to become steady, but with both of them running I run into this problem.

Tang Salad
04/15/2007, 06:03 AM
There is a chance the two drains to the sump, or the overflow itself, cannot keep up with the flow added by the second pump.

What kind of drains are you running? Dursos or something different?

Goodwin9
04/15/2007, 06:12 AM
<a href=showthread.php?s=&postid=9729932#post9729932 target=_blank>Originally posted</a> by Tang Salad
There is a chance the two drains to the sump, or the overflow itself, cannot keep up with the flow added by the second pump.

What kind of drains are you running? Dursos or something different?

Dursos I believe?

Tang Salad
04/15/2007, 06:46 AM
Ok, well the Dursos should have small vent holes in the top caps. These need to be enlarged in order to stop the surging you're getting.

If you need more help, post a pic of the dursos and I'll take a look.

fras
04/15/2007, 06:47 AM
have you tried different sized holes in your durso cap? They will need adjusting for your new higher flow.

edit: doh beaten to it!

Goodwin9
04/15/2007, 01:19 PM
<a href=showthread.php?s=&postid=9730016#post9730016 target=_blank>Originally posted</a> by Tang Salad
Ok, well the Dursos should have small vent holes in the top caps. These need to be enlarged in order to stop the surging you're getting.

If you need more help, post a pic of the dursos and I'll take a look. Here is the best picture I could get from one of the over flow boxes.

http://i102.photobucket.com/albums/m95/goodwin9/470%20Return/100_2148.jpg

Hop
04/15/2007, 01:26 PM
That's fine, but you need to balance the air/water mix going into the standpipe. I've seen people and I will be using, a 3/8" gate valve on the top for fine tuning. It may work in your case as well.

Goodwin9
04/21/2007, 03:46 PM
Finally solved the problem by adding a couple of vents on each of the return lines coming into the sump. One was T'd off to feed the new skimmer while the second just had the vent stack added. Amazing how it even out the flow coming from the tank.

http://i102.photobucket.com/albums/m95/goodwin9/470%20Return/ventstacks1.jpg

http://i102.photobucket.com/albums/m95/goodwin9/470%20Return/ventstacks2.jpg