March 24 2017 at 2:50pm
First I apologize for the long post :).
Just based on those numbers, it seems like there is a problem with your membrane, and that there is floaty white stuff)
Based on your post above that your have the mighty mite from airwater ice (50gpd with a minimum rejection rate of 96%)Membrane Rejection Rate
Tap TDS: 108 (X)RO TDS: 32 (Y)
(X-Y) = 108-32 = 76(X-Y) / X = 76/108 = 70.37% rejection rate
So 70.37% is what your membrane is currently rejecting, so in Filmtecs specs it should be replaced since it is below the 96% minimum.
As far as output goes, the "Acceptable" ratio of production to waste is somewhere between 1part production to 5 parts waste (1/5) and (1/3).
I can already tell that something is off with your membrane because my 90GPD unit produces about 2 3/4 cups of waste in 1 minute and since your unit does 40GPD less yet your waste is 5x mine. Your waste should theoretically be less.
Just for the sake of completeness lets figure out what your max production output should be so that we can figure out what your waste output should be.Membrane Production Calculation
Expected GPD = Rated GPD * WaterPressureCorrection * TemperatureCorrection
Since your Water Pressure is unknown we will use the average (55psi) and since your Temperature is unknown we will use my average water temperature (61F) :).
TemperatureCorrection(61) = 0.754WaterPressureCorrection(55) = 55 / 61 = .902Expected GPD = 50GPD * .902 * .754 = 34GPD is probably pretty close to the most you should get from your unit per day. Since the most waste you should get is 5 times the production 5 * 34 = 170Gallons of waste or 170/1440(minutes in a day) = .118(Gallons per minute)
16 cups of water per gallon .. so .118gallons per minute = 1.888 cups of waste water per minute (MAX at a 5/1 ratio with a 50GPD unit)...TLDR; I think your membrane is bad and you should replace that before adding more resin canisters
There may be some mistakes in the math above, but based on your waste output alone, I would still think the membrane is bad.