sizing skimmer

So my question is a simple question but probably not simple to answer. How do you know when a skimmer is under sized? Does it hurt anything by using a larger skimmer than water volume? I couldn’t find anything that clearly explained any of these.

As far as I’ve have learned about protein skimming. The bigger and the more bubbles it makes the more DOC it take out of the water. Less DOC for nuisance algae to feed on.

Here’s some reading. The second link has some good info.

http://www.reefkeeping.com/issues/2002-06/fm/feature/

http://www.reefs.org/forums/topic13837.html

I think nowadays skimmers are pretty much sized appropriately from the manufacturer. A few years back I would disagree, but now with the newer, better quality pumps and the way skimmers can be fine tuned with valves, etc., I think they’re pretty spot on.

Not a scientific way to look at it, but if your skimmer is constantly pulling waste and you’re emptying the cup often, then it’s probably under rated. If your skimmer isn’t really doing anything, then you’re probably over rated. Of course, there are always caveats with everything - over / underfeeding, running a fuge, DSB, running wet vs dry… it all affects skimmer performance.

Well, there’s tank size. and then there is tank bio load to consider too. if your tank is fully packed, with corals and fish, you might need one size bigger. I think they size em by moderate scales of bioload.

[quote=“Sneeyatch, post:3, topic:7514”]
I think nowadays skimmers are pretty much sized appropriately from the manufacturer. A few years back I would disagree, but now with the newer, better quality pumps and the way skimmers can be fine tuned with valves, etc., I think they’re pretty spot on.

Not a scientific way to look at it, but if your skimmer is constantly pulling waste and you’re emptying the cup often, then it’s probably under rated. If your skimmer isn’t really doing anything, then you’re probably over rated. Of course, there are always caveats with everything - over / underfeeding, running a fuge, DSB, running wet vs dry… it all affects skimmer performance.[/quote]
I think the same as this if it constantly bubbles and works it can’t catch up. I would think it should produce a lot and then it should slack off consistently, if theres a spike it should foam a lot then drop down.

Ok so then my next question is. How long should it take for the skimmer cup to fill? My cup is almost 2 weeks before it needs to be emptied. There is the normal thick paste in the neck but not much in the cup.

that would depend on how its set I dont empty mine for a month or more but if i make it wetter it’ll have to be done every day

My water level is at the max line. And it doesn’t skim much. And don’t you have your skimmer drain into a bucket? So how would you know when you have to empty?

If not much skimmate. Wouldn’t that be considered a good thing? Meaning that your water is clean and not too much DOC.

This is what I’m trying to find out. Is it that the water is clean or is it that the skimmer can’t keep up?

I skim dry the bucket is for accidents. I would just go by the ratings. They label them with low to high load. I don’t think you could have one too big. Is there a problem with yours? What’s happening that makes you question the skimmer?

[quote=“beadlocked450r, post:10, topic:7514”]
This is what I’m trying to find out. Is it that the water is clean or is it that the skimmer can’t keep up?[/quote]

Unfortunately, it could be either way. I see in your sig you have a rather large system and a frag tank. Are they all plumbed together? If so, how much total water volume are you looking at? Fish load and what type of fish? Are you running a fuge? Carbon? GFO? Biopellets? Zeo? Feeding and how much are you feeding? Dosing liquid foods? Even down to how often are your hands in the tank?

What skimmer are you using? Maybe I missed it somewhere?

Todd, yes everything is all tied together. It’s almost 400g. I have about 20 or so fish between all the tanks. I have 75g fug with macros,80 frag tank. The skimmer is reef octopus xs250. Not the Diablo. I think it’s rated for 250-300g. This is why I’m asking these questions. Is this skimmer over worked? And how can I confirm it is or isnt? I know by the ratings it might be undersized but what will happen when it can’t handle the bio load? As for feeding I probably don’t feed enough. I haven’t been adding any liquid food in almost a year. I do have skimmer on a timer and it goes off for about 4 hrs in the middle of the night.

Tim I’m not having any problems yet! I don’t want any either! Other then a little red slime algae.im trying to get a better understanding as to what I need to be looking for as this system matures and demands more.

This is the one with the Sicce pumps and something like a 10" neck?

I would think given the fuge, light feeding and water volume, this skimmer would work fine. I saw that most folks are rating this skimmer at around the 300 gallon range but if you’re getting cyano, I would just try to skim it a little wetter and see if you get better production out of it.

I’m using the Octopus Classic 150SSS on my 90 which is rated up to 200 gallons and it’s running their newer Aquatrance pump. All in all with the sump and stuff and rock displacement I’m ptobably looking at around 100 gallons of free water. I was going to go with the smaller version (110SSS) but I wanted to keep a higher fish population and I feed the tank like crazy. I run it somewhere in the middle between wet & dry and I have to empty my cup about every week and a half.

Just remember we can always add the scrubbers back in. I may cut mine down to size soon and try it again. It works just too well

Is and algae scrubber any different then having the 75g fug and the 90g of water with a 2’×2’square wad of cheato?

yeah the scrubber is much better than any of those it caused me issues because it cleaned too well thats why if I use it again i will cut it down