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View Full Version : Gravity fed or pump fed protein skimmer?


michellejy
10/09/2008, 07:59 AM
I have a DAS EX-2 that is not in the sump. The manufacturer recommends that this skimmer should be fed directly from the overflow, but it seems like most skimmers have a pump in the sump feeding water to the protein skimmer.

Are there specific problems I should be aware of with either method? Is one way considered better?

Texastravis
10/09/2008, 08:04 AM
When feeding through gravity make sure that you put a T fitting from the overflow part of the overflow box and have a ball valve or gate valve on each end. This way you can control the flow to the skimmer. Keep adjusting the valve until you get the recommended flow for that model of skimmer.

Gravity fed is the way to go. Feeding with a pump is way to costly electricity wise IMO. Just one more thing to plug in. Often times when using a feed pump with bigger skimmers this can cause a massive overflow of water onto the floor. When elec goes out the pump runs off a syphon while the skimmer is unplugged causing overflowing.

If you dont want gravity then the next best choice IMO is to feed it off a branch from you return pump, again add a T and valves to do this

tiger_eyed1
10/10/2008, 06:44 AM
If gravity fed works for you, GREAT!

I tried it twice without any success.

1st try
Equipment: MR2 Being fed from 1 AGA Megaflow
Return pump was mag18
Results: Not enough flow to skim

2nd try
I added a 2nd Mag18 to the setup and AHHHH, the skimmer started bubbling but when I looked up top in the display the two megaflows couldn’t keep up. The skimmer was restricting to much drainage and about to start a flood. I tried my best to get them leveled out without restricting the pumps. I didn’t want to over engineer so I just put the pump back on the skimmer.

Unrestricted, the two megaflows could handle the 2 mag18’s. When I put the skimmer on one of the drain lines, it was about to cause a flood from the display. Your results may vary.

elmosz1
10/10/2008, 08:22 AM
You may have enough reserve on your return pump to feed the skimmer as well. Especially, since you only need a sump turnover
of 3-5X your display volume per hour. This lower turnover alows more dissolved organics to present themselves to the skimmer and may preclude the need for a dedicated skimmer pump.

mg426
10/10/2008, 10:37 AM
I direct fed an ASM G3 from my overflow. It worked very bwell for me. I used the ball valve/tee method as mentioned above.

michellejy
10/10/2008, 11:43 AM
Okay, one of my concerns was definitely the protein skimmer overflowing since it is not in the sump. Thank you for explaining how to keep that from happening.

forensicdoc
10/10/2008, 08:56 PM
I am currently doing it both ways.

My 190 gallon reef has a skimmer that is gravity fed. It has the t-fitting that is well described by texastravis. The claimed advantage is that the "raw" water from the tank is fed directly into the skimmer, reportedly leading to better efficiency. The flow rate through and water level in the sump can be adjusted to proper levels. The only "down" side I have noted is that larger pieces (like a piece of macroalgae) can flow directly into the skimmer and then tend to have to be fished out.

My 290 predator has a pump feeding the skimmer from the sump. It uses electricity, so it is not as energy efficient as gravity, but you can maximize flow rates through a given diameter of pipe this way. The flow rates and levels can also be easily adjusted. Since it is fed from a pump, you can screen any larger pieces before they can reach the skimmer. I have to say that I do not agree with texastravis on the risk of a flood. If the feeder pump loses power, the water level in the skimmer will drop, because even though it is fed by electricity, it empties back into the sump with gravity.

My experience has been that both methods appear to work well. I am unsure as to whether one method really turns out to be significantly superior to the other. My inclination is to use gravity since it is more energy efficient.