Why does skimmer height matter?

[greech]

Did a search and couldn't really find an answer. Most posts about skimmer height are more questions about what the ideal height is for a specific skimmer. Maybe a silly question but I cannot get my skimmer (SWC 120) to skim like I have seen others. Thought understanding why skimmer height makes a difference might help me figure it out. I assume the deeper the skimmer the wetter it will skim? Another question would be is the height measured from the skimmer input or the base of the skimmer? I have about 1.5" difference between the two

I've had the skimmer for over a year and it doesn't seem to ever produce the skimmate I see other 120's produce. It is typically a yellow/dark brown tea or a very dry particulate foam with little water. I feel like I am constant adjusting it. I have had the skimmer in a constant head of water ranging from 5.5" to about 7.5" and adjusted the air and water level at each height.

 

[vikubz]

I believe the idea is that the taller skimmer chamber gives the air bubbles more contact time with the water so they pick up more organics on the way up to the collection cup. Keep your water level constant, then tune in the skimmer. Maybe you just don't have that much bioload.

 

[greech]

So does that imply a shallower depth is typically better?

I have the 4 fish in my signature but the midas was just added to the display this week so I have only had 3 fish for about the last 8 months. i do feed the tank daily and pretty well. No nuisance algae to speak of and corals doing pretty well.

 

[elegance coral]

That's a good skimmer. You probably don't have the load to feed it. You're not going to get a great deal of skimmit from a clean 40 breeder with four small fish.

 

[SkullV]

That's a good skimmer. You probably don't have the load to feed it. You're not going to get a great deal of skimmit from a clean 40 breeder with four small fish.

+1 bioload has a lot to do with it. In my 100g FOWLR my BM NAC6 pulled out black thick skimmate, in my 35g reef system the same skimmer pulls out very little skimmate and what it does pull is dark tea colored. The SWC120 has a recommended water depth of 5-8" directly from SWC. I have found that the upper end of that recommendation is usually what you want for max performance.

 

[vikubz]

Not familiar with this skimmer, but a consistent level will help you tune in the skimmer. I think your pump will pull more air the closer it is to the surface, mine does. I try to avoid skimmate envy. As someone once said, "Whatever you get for skimmate, would you pour that back into your tank?"

 

[greech]

Really?

Before I bought the skimmer everyone seemed to recommend to get a little larger skimmer than you need. The 120 is rate for a heavy bioload 55 and a light bioload 90. I would guess I have 55 gallons of water in my total system. Is 4 fish in a 40B considered a light bioload? I was worried about adding the midas thinking it might be a little crowded.

Good point vikubz. Did you mean constant level as in water level around the skimmer or inside? The skimmer is in a constant baffled area. I manually have adjusted using a taller/shorter stand.

Thanks SkullV. I can lower it to 8" but is it 8" from the pump input or base of the skimmer? Again, there is about a 1.5" difference.

 

[SkullV]

For that skimmer you have an extremely light bioload.

 

[greech]

I would have never guessed that was the issue. Thank you.

So is there a problem with having an oversized skimmer? Will my tank do even better with a smaller skimmer? I don't think I want to add more fish but I hadn't really considered it.

 

[SkullV]

If your tank is doing fine now then I wouldn't worry about it. You have a nice buffer zone for feeding more, and adding other organics (consider vodka dosing/bio pellets) without running into issues. You also have a good reason to upgrade to a 55 or 75g!

 

[greech]

You also have a good reason to upgrade to a 55 or 75g!

Aww, why'd you have to go and say that :lmao:

My ideal tank is a 120 so that will be my next tank. Probably have to upgrade the skimmer at that point though .

 

[SkullV]

Aww, why'd you have to go and say that :lmao:

My ideal tank is a 120 so that will be my next tank. Probably have to upgrade the skimmer at that point though .

Yes you will. I am planning on running my NAC6 on my new 75g in a couple months when I finally get around to putting it together. Any larger then that and I would need a new skimmer.