Max safe PPM out of RO/DI

[gnorman]

Hello,
Currently, I have been using an RO/DI unit to create sw and for top-offs. I wanted to know what is the highest ppm allowance after it has been through the unit. Currently, my tap is 480ppm (I know, really high; and it is barely legal too California is 500ppm max for tap) Anyway, I am running a 100gpd (i will be switching to a 75gpd for a higher efficiency rating once it comes in) and it is getting it down to about 40ppm. Once it hits the DI, it gets it between 3-10ppm. Is 10ppm too much?
Thanks for your insight.

 

[bang guy]

Safe depends on the contaminants. Coming out of your RO is mostly Silicates and Phosphates. Silicates feed Diatom blooms but are otherwise harmless. Phosphates fuel all algae, good & bad, as well as fueling Cyanobacter and will inhibit calcification in skeleton building animals like Corals, Clams, and Snails.
So, even 40 TDS could be fine if it's just Silicates and you have animals that can consume the extra Diatoms. Unfortunately there's probably a good amount of Phosphate in there but a test would let you know.
Coming out of the DI your water should be 0 - 1 TDS. If it's not then check to make sure that your DI cartridge is mounted vertically.