Skimmer Size and over-skimming....

[brogers]

Can I please have some input/opinions on getting a skimmer that is rated significantly larger than recommended size. I have a 40 gallon system and was thinking of purchasing a reef octopus with a rating between 180-265. Is over-skimming really an issue?!

 

[vlangel]

I have seahorses so overskimming is not possible. However if you want bright beautiful coral and only have a normal fish load over-skimming can starve your coral so that they either don't thrive or they are lack luster in appearance. I think having a bit larger is nice in case you upgrade or want to really heavily stock your tank with lots of fish but I would not go that much bigger if it were me.

 

[SuperDragon]

A little oversized 2-2.5x is usually ok, there are pleany of people that go larger. Keep in mind to run consistently, an appropriate neck size vs. a neck that is too large for your system. Large oversized necks skim once in awhile when the lights go out and tend to overflow if you adjust too high. Sump size is a concern as well. Other weird points are if you get a neck cleaner it effectively cuts the neck size in half or two smaller necks.
So for your application a smaller neck 6" should suffice. Pumps, warranty, and even branding affect the price.
Larger sizes give room from upgrading. Nothing is going to die with a larger skimmer.

 

[Randy Holmes-Farley Verified Community Expert]

This is a question that has been asked for decades, since skimmers came out, but I'm still not sure what it would mean to "overskim".

If it just means too low of nutrients, that isn't necessarily overskimming as opposed to not supplying adequate nutrition.