skimmer size

This may seem like a dumb question, but I'm going to ask it anyway I am looking to upgrade my skimmer and I always hear people say they try to choose a skimmer that is rated to at least 2x the volume of your system. My question is not so much about whether people use that rule of thumb or not, but more so are you talking 2x your DT volume or 2x the volume of your total system including sump etc?

 

Because new reefers are afraid of asking "dumb" questions they often expriance tank crashes. Usually the volume of water ends up to about the volume of your tank. The volume we are looking at is the tank+sump-rock,sand,eqipment. Anywat,it is a rull of thumb so you don't need to find one that is excectly twice the size that you need.

 

Mike it really depends on the type of system, types of animals you are housing,feeding habits, maintenance.. If you plan on using this for a Refugium/sump then you can try to match the GPH you have flowing through the sump ..In theory this should mean dirty water goes in clean comes out.however GPH through the sump is not critical to how the skimmer performs .Most peoples skimmer actually pulls more GPH then the sump return doess so more dwell time may mean better performance.:-/
Depending on the Brand of skimmer you choose most good companies estimates are fairly acurate and I usually don't add the sump volume.Don't forget most reef tanks are full of rock,corals,sand,and fish so the actual gallonage is much smaller then what you start with.
Everyone's sytem is different so the "formula's " you hear are general guides at best.
Pick a skimmer that comes with a reliable/economical pump.

 

Thanks Guys,
I have a 125g tank that has been set up since April of last year. Mostly LPS and softies right now, but may add SPS at some point. I am currently installing a 55g basement sump. Up to this point I have been using an Aqua C remora Pro HOB skimmer. It does a decent job but I think it is a bit undersized. I was thinking of getting a NWB 8" Reef Octopus skimmer. It is rated up to 250 gallons so I'm thinking it should be good?

 

I think that would be fine . However If I were making the choice for my tank, it would be closer to the 200 gallon rating IMO. I like my skimmer to pull out skimmate constantly rather than pull it out when there's a higher concentration.

 

While I have never used that particular brand they seem well built and get good reviews.. I will bring this thread to the attention of some of our more worldly skimmer guys.FWIW I run a WM skimmer and LOVE IT!But Jon won't get off his lazy rearend and produce them anymore.LOL JK.

Huh????

 

An oversized skimmer requires a larger amount of protein to skim when it's rated bigger than the tank.

 

My skimmer pulls skimmate all the time and it's rated for 160 and up gallon tank. This is on a 40 gallon that has three fish that gets fed twice a week at the moment.

It's a warner marine mf-161 or skimz sm-161.

 

What???

 

I'm honestly not sure how to explain it in a simple form as it's pretty simple already..


A bigger skimmer requires more protein to make the neck foam to the point where it overflows.

If a skimmer is too big for a tank, it will "burp" rather than constantly pull skimmate out.

I did a google search to find other peoples explanations..

When a skimmer is larger and the system is a low nutrient system, then there might not be enough organics for the skimmer to maintain a head to export the skimmate. It is kinda like building a large car engine and using an undersized fuel pump... so the engine is just starved. A lot of times, folks will buy a big skimmer and it will do well for a few months. After a while, the skimmate production drops... In reality, the skimmer caught up to the tank's organics and then settled down to a more normal output. But, some folks will see this as their current skimmer "wearing down" and go out and buy the next size up. As a result, this skimmer does "ok" for a while the completely drops off to near nothing. That is over skimming.

Large skimmers, because of their large neck size requires more organics to build the head than smaller neck skimmers. However, large skimmer necks handle more air then smaller ones so they can skim more when there is enough organics.