Who rates skimmers
 

Why are skimmers rated for system gallons rather than for bio-load? A 200 g system has little load compared to a fish only 100g

I wana know too. And why, are some WAY more expensive than others? Cause it's made in Germany, means it's 3x the price?

Why not ask the skimmer manufacturer? Aren't they the experts?

Is because you make something, does that instantly make you an expert? :D

The ratings are ridiculous. I think a BakPak is rated for 100 gallons or something stupid like that. It seems the lower the quality, the higher the rating. I think it's something you just need to get a feel for. Also, a lot of people think that if they have a 180 gallon tank that a skimmer that is good for 180 gallons is a perfect match. Well, that's just silly, you're running the skimmer as MAX suggested volume?? The skimmer should be bigger than the water volume.

Nah that's not what I was getting at, I'm certainly no expert. It was sarcasm, kind of an inside joke to another thread :wink:

Skimmer ratings will never be accurate, what works for one won't work for another. The ratings are general guidelines and some common discretion is required from the buyer. However for the most part skimmer ratings aren't that off for the major brands (cheap novelty brands aside). I've used a Euro Reef 180 on a ~250 gallon decently stocked reef tank and it worked well for the system. Also your skimmer dependence actually decreases with a fish only, yes you can use a larger one and it can be beneficial but the higher nutrients won't necessarily cause a problem. Many people with FOWLR tanks don't even use skimmers and do quite well.
I can't see a bio-load rating being practical, how exactly do you rate bio-load? Either way it's common sense, if you plan on having a higher than normal bio-load for your tank you always have the option of using a larger skimmer. One could simply assume the rating is based on a standard load for the given volume.

Just an off the cuff though, could you not rate a skimmer based on ml/hour of "dense" skimmate (i know dense is a relative term) so at least all skimmers are on a level playing field. You could then calculate how many ml/hr you would need based on your bioload and needs. (no I don't know what that calculation would be, but it wouldn't take much other than experimenting with a baseline skimmer, and varying bio-loads to come up with an approximation)

I wouldn't want to be that sales guy trying to sell those skimmers :wink:
Simpler is usually better and specifying specifics like that will cause huge issues as results will always vary. It's one thing to say this skimmer will typically handle 200 gallons of tank volume but to say this skimmer will produce X amount of skim mate is another story. There are certainly skimmers out there that have bad ratings, seaclones are one that come to mind, but good quality skimmers are rated fairly decent in my books, and on occasion some manufacturers do actually give a few rated volumes based on high and low bio-loads.
I think too much thought is going into this, consider all the variables involved in actually determining the right skimmer. Amount of fish and other livestock, size of fish and other livestock, type of fish and other livestock, amount of food feed, allowable nutrient level (sps-low, lps-med, fowlr-high), tank volume, and so on. I mean these ratings are just general guidelines, just like fuel ecomony ratings on cars, they aren't that accurate either but there are too many variables involved for it to be accurate for each person.

One thing I know, BOTH my skimmers suck, and Im to broke to get BK's LMAO

Tunze gives you a little more help by listing a "maximum" tank size for their skimmers which you subtract down from depending on what you are keeping in the tank (e.g. SPS, LPS, softies, FO).