Wher do i buy flow meter

Just wondering if anyone knows where i can get a flow meter that reads over 250 gph, toms makes one but its not rated for saltwater. I want one for my steralizer that needs 290 gph. I realize i can just run the water in a bucket to figure it out but i want a way to constantly monitor it. I know alot of people say not to run one but i just use it as a safeguard when i add fish to my main tank! better safe than sorry lol

 

Adam, That flow meter isnt for use in saltwater use just freshwater. Thanks for the response!

 

Adam, from the looks of it thats what i will have to do. Like you said over 250 their expensive plus you have to have to drill a a hole in the water line and clamp it onto the water line. they use a rubber seal between the water line and meter im not sure if i trust that. a couple hundred gallons of water on the floor from a leaking seal would prob be bad thing lol. one with a hose barb or in line would be better! I looked online for abought a hour and cant find anything. well if anyone else  has any input i would apreciate it.
Brian