Don't know I have a similar system (stats wise) and I think it was 4-6 hundred ( water softener and RO was 1k) so sure he is getting some markup but as long as it is NSF I would think that you are ok.... also 2.5g bottle isn't nearly enough, you will only be able to get 1-1.5g out at any time due to the way the pressure thingy works. See if you can't get a 5g or so bottle or if you can chain multiple bottles together.
BUB

