Sump Baffle Broke, and I am Redesigning My Sump: Will this Design Work?

[SkyReef]

Hi, all:

I was all set to water-test my set-up, which is a modification to my Nano-Cube + BioCube + sump. Then, my cheapo 1/8" baffle cracked in my sump, necessitating that I replace that baffle with 1/4" glass. Since I am going to replace the one cheapo baffle, I will replace the second, as well. Going for broke, this setback gives me a new opportunity to add a 3rd baffle, incorporating a bubble trap. Here is my design, for which I have questions. I post the schematic of the sump design below.

Question 1: Since I am mixing the drain lines of two tanks into a single sump (one set of return lines, lines 1-3, terminates in the protein-skimmer section and the other set of return lines, lines 4-6, terminates in the post-bubble-trap space before the return section because I don't want lines 4-6 (coming from a dedicated, stand-alone refugium) to get processed by the protein skimmer), does the third baffle need to be lower than the first baffle? I presume it does because water will be flowing into the area immediately preceding the 3rd baffle and could cause undesireable backflow or backpressure, if the 3rd baffle is not lower than the first.

Question 2: Are the height differences in the baffles appropriate: (a) the first baffle is 12" high; the bubble-trap baffle is 14" tall, but sits 15" high, given its one-inch gap at the bottom of the sump; and (3) the third baffle is one-inch lower than the first baffle, to reduce any backflow or back pressure on the flow established by Drain Lines 1-3--or can Baffle 3 be the same height as Baffle 1?

Question 3: are the high and low water levels of the return section appropriately set: (a) the high water mark would go to 9.0 inches (just two inches below the third baffle--is that enough space or do I need more clearance from the high-water mark and the height of that 3rd baffle?), creating a volume in the return section of 1.7 gallons of water; and (b) the low water mark would be 7.0 inches (does that height of water create enough hydrostatic pressure on water exiting the sump through the bulkhead below?), creating a volume in the return section of 1.3 gallons of water?

I wanted to make sure that the height differentials between the baffles and the high-and-low water-levels in the return section don't cause any backflow or back-pressure problems. What do you think of this design? Will it work?

Your help is greatly appreciated. Thanks!
http://i883.photobucket.com/albums/ac35/SkyReef/2011-03-21SumpDesign.jpg

[TellyFish]

I would be careful in regards to micro-bubbles and bypassing the bubble trap with the yellow drain line. Otherwise, it looks fine to me... similar to my current setup.

[SkyReef]

I would be careful in regards to micro-bubbles and bypassing the bubble trap with the yellow drain line. Otherwise, it looks fine to me... similar to my current setup.

Thanks for your response, TellyFish. Would it be better to move the yellow lines upstream by one chamber, immediately before the bubble trap? If I did that, wouldn't water from the yellow lines stray into the first chamber, which houses the protein skimmer? I was hoping to have the water from the yellow lines bypass the skimmer.

Also, could you post a design or picture that depicts your setup that is similar to mine? I'd like to see how you did yours, and images are easier to grasp than words.

Thanks!

[Midnightsun]

You should be fine the way you have it drawn up. The fuge pump intake is submerged and the return line is submerged on a low flow application.

[SkyReef]

You should be fine the way you have it drawn up. The fuge pump intake is submerged and the return line is submerged on a low flow application.

Thanks, Midnight Sun. On second thought, would it be better to have the return line (yellow in the diagram) before the bubble trap, just after the skimmer chamber ?

[SkyReef]

After further consideration, a modified design from that posted above may be appropriate. I think I should move Drain Line Nos. 4-6 to a position UPstream of the bubble trap, away from its current DOWNstream position, depicted in the diagram above. This will reduce opposing-directional water flow, and both inputs of water from Drain Line Nos. 1-3 and 4-6 will be flowing in parallel motion, decreasing the likelihood of turbulence-created microbubbles.

Any micro bubbles created by either Drain Line Nos. 1-3 and 4-6 can be alleviated by the bubble trap, which both streams of water will pass. Finally, Drain Line Nos. 4-6 will not likely merge back into the Skimmer Chamber No. 1 because there is a forward-momentum flow established by Drain Line Nos. 1-3, which would counteract any backward flow caused by Drain Line Nos. 4-6. As well, the downard positioning of the water jets exiting Drain Line Nos. 4-6 would tend to carry forward, downstream, not backward, upstream. You'll recall that this is desireable because I don't want the refugium waters of Drain Line Nos. 4-6 to migrate into the Protein Skimmer housed in the First Chamber of the sump.

Presuming this new design presents an improvement over that design originally posted above, here is a new diagram of this modified design. In this new diagram, Drain Line Nos. 4-6 have been moved UPstream of the bubble trap, from their prior placement DOWNstream of the bubble trap in the earlier design.

Thanks to those who contributed questions and ideas. Any further thoughts and insights would be most appreciated. Thanks!

New Design:

http://i883.photobucket.com/albums/ac35/SkyReef/2011-03-22SumpDesign-Version2.jpg