Question about UV tank size ratings

[forddna]

I have a Coralife Turbo Twist 6x 18w. It is rated for 250 gallons. I just purchased a 220 tank, and I'll be using a 40g sump.
So, I'm pushing the limits of this UV, according to their tank size rating. Does that matter? How is the tank size rating figured??

 

[scsinet]

Best guess really is how they are figured. Manufacturers can rate their products' capacity arbitrarily, so there is nothing you can count on.
The effeciveness of the unit is based on how fast you flow water trough it, which in turn affects the turnover rate through the unit. 18W shouldn't have anything more than 100gph going through, so that's not a lot of turnover. Personally, I'd use a 40W on a tank this size.

 

[forddna]

The reason I'm wanting to use it is that I already own it, it's brand new, and I have had a difficult time selling it w/o GIVING it away. So I'd rather keep it, if at all possible.

 

[forddna]

BTW, this is going to be a FOWLR tank, if that makes any difference.

 

[scsinet]

Well the unit may be underpowered, but it will do as best as it can on that tank.

 

[forddna]

Hmm...I guess I can try to sell it again and save for a bigger one.

 

[hobrien]

How much will you want for it

 

[forddna]

$100 plus shipping.

 

[bergamer]

you need at least 60w unit, better to get an 80w.