Skimmer discussion

[Mark_C]

So, in researching my next moves on the new tank I found a few interesting items on skimmers and how they relate to the system’s return pump.


In general, most say that:

1. You should have a skimmer rated (at least) to your bioload

2. You should match return pump to the skimmer rating


Number 2 intrigued me.


I’m temporarily using an Aqueon 1700, rated up to 449gph.

My head height is 5’ which put the pump at approximately 380-400gph at maximum.

My skimmer, a Reef Octopus Classic 110 Internal, moves 92gph.


Please note…

I know I should get a lager skimmer, but for the moment lets assume I keep this one for debate sake.

I’m supplementing water turnover in tank with a Gyre and a Vortek.


So…

Do I need to dial back the return pump to match the skimmer or should I consider a smaller volume return pump - will it make the skimmer more effective?

I understand that the slower the water moves around the skimmer, the more of it will be ‘re-drawn’ in for processing, but…

If the skimmer is constantly moving 92gph through itself and the water is constantly circulating, does it even matter?

 

[jgraz]

I can't see how it would matter. As long as the skimmer is processing dirty water then it's doing its job. I can't imagine it's possible to set it up so all water is skimmed. This is why we generally have several different means of export, skimmer, gfo, gac, macro, and so on. Not one part can process everything, but all together we get as close as we can.

 

[redfishbluefish]

I agree, I'm scratching my head on that #2 as well. So what they are saying is the the flow rate coming into the skimmer section should equal the pump rating on the skimmer.

My first question....do you match what that skimmer pump is rated at. That is, a pump rated at lets say 700 gph will not pump 700 gph when set up with a venture for sucking in air. Using hand waving calculations, let's say it's now down to 500 gph. Do I match that or the 700?

And here's my other question.....I have two drains coming into my sump; one for the skimmer section and one for the refugium. If I assume half the volume goes to the skimmer side, do I match that volume?

So here is what I have.....a MAG 9.5 as a return pump (but again two drains coming into the sump) and an Atman (POC) 2500 pump on my skimmer rated for 700 gph when used as a pump. Assuming no headloss (I know, meaningless!), the skimmer section is recieving 475 gph. I think I might be pretty close.

I think what they are saying is that you want your skimmer pump rating equal to easily handle all the water coming into that section. If the skimmer pump rating is far below the inflow rate, you end up circulating dirty water. But I'm guessing.

 

[AqOb]

Think about it by exaggerating the numbers. If you had a system that needs a 10,000 gph return pump, would a skimmer that processes 100gph be efficient? No, you would want a skimmer that can handle close to the flow through to maximize efficiency. I prefer to word #2 reverse. If you need a 700gph return pump match your skimmer to that rating.... within reason...