is this a good filter?

I bought a RODI 75GPD purely H20 optima, used once he didnt like it and sold it for $50.00;D. want to know if it was worth it or was it a waste of money?

 

PurelyH2o is a good vendor and the Optima series are a good value.
The only way to tell if it was a good deal or not is with a TDS meter. You need to know three numbers to calculate the rejection rate and system efficiency.
You need the tap water TDS, RO only TDS and RO/DI TDS.
Tale the first two, tap and RO only and od some quick math.
Using some made up numbers lets say your tap water TDS is 250 and your RO only TDS is 5. 250-5=245, 245/250=.98, .98x100=98% rejection rate which is where you want to be.
Basically its tap water TDS minus RO only TDS, divide that by the original tap waterTDS then multiply by 100 to get the removal efficiency or rejection rate.

The RO/DI TDS should be 0 regardless of what the othet two are, if its not 0 then you need DI resin at a minimum, the rejection rate will tell you if you need a new membrane.

The prefilter and carbon block get replaced every 6 months regardless of how much or little watre has been made.

 

Sounds like a pretty good deal, may want to change the filters though just to be sure. if you dont have access to a TDS meter