Can i over skim?

menelaos · Sep 2, 2015

I just found a deal on some used equipment i need to finally put up my tank on craigslist. My tank is a 90 gallon acrylic bow front with either a 25 or 30 gallon sump. I can find a decent skimmer for cheap but its rated up to a 250 gallon. Should i get it or will it be to much. I need to find out fast as this deal will not be around long.

Thanks..

Tahoe61 · Sep 2, 2015

That should be fine as long as it's in good working condition, a skimmer can only remove what is already there. Mother natures skimmer is much much larger.

ReefMadScientist · Sep 2, 2015

I have always stood by the rule to buy a skimmer 2x+ your water volume.

I doubt a skimmer will purify the water too clean. Maybe with Carbon, GFO (mass amounts), and large skimmer.

luke33 · Sep 2, 2015

Sure its possible under the right settings, but I don't think it happens that often. Generally if your skimmer is to big for your tank it doesn't have enough organics in the water column to build a foam head and skim consistently. So you'll have periodic soda fizz action instead of foam head action. If you were carbon dosing heavy and skimming heavy, barebottom, lots of flow, and not feeding a ton, I could see you sterilizing your tank, or all of the above with GFO, lots of carbon...etc.

AdamNC · Sep 3, 2015

I run a 29 gallon standard with 20 gallons volume of water, use a skimmer rated for 75 gallons and have no issues.

sonnus · Sep 3, 2015

The problem with a massively oversized skimmer is dialing it in. Like luke33 said, you'll skim for a while them not skim at all. I've seen significantly oversized skimmers only produce skim mate for 1-2 days and then not skim anything for 2 weeks straight. You just have to resist the urge to constantly make adjustments to it otherwise you'll constant be overflowing the skimmer when it does decide to skim.

I personally don't think it's worth the trouble but if you don't mind dealing with it then it will be fine.

Kungpaoshizi · Sep 8, 2015

I'm a firm believe you can skim too much. Going for a number of years and from different skimmers, all skimming 24/7 to turning it off for 6 hours a day(leng sy) I saw a huge difference and less rtn/stn events.

Tdawg · Dec 30, 2017

Hey KU, what's an rtn/stn event? thanks

redfishbluefish · Dec 30, 2017

I've run both an MRC I and an MRC II on a 90 gallon tank, with the MRC II rated for 300 gallons. I believe there is no such thing as overskimming with skimmers only capable of pulling out about 30% of what they could pull out. Always produced nice dark skimmate. If the organics are not there to pull out, it will simple put out less skimmate....no harm done.

K. Steven · Dec 30, 2017

Tdawg said:
Hey KU, what's an rtn/stn event? thanks

Rapid tissue necrosis (RTN) and slow tissue necrosis (STN)

HB AL · Dec 30, 2017

I would do it, you should have no ill effects.

Bug235 · Dec 30, 2017

menelaos said:
I just found a deal on some used equipment i need to finally put up my tank on craigslist. My tank is a 90 gallon acrylic bow front with either a 25 or 30 gallon sump. I can find a decent skimmer for cheap but its rated up to a 250 gallon. Should i get it or will it be to much. I need to find out fast as this deal will not be around long.

Thanks..

Do it no issue at all!