Depleting cation media extremely fast

[chiplake]

Exhausted trying to make perfect RODI for my salt tanks. When I first started trying to make water from my well, I was depleting my anion media within 20 gallons. A suggestion from this site was to add in sodium hydroxide(caustic soda) to bond to the CO2 in my well water and turn it to sodium bicarbonate. Added 1/2 lb of food grade caustic soda to 45gals of water mixed and aerated for 48 hrs. Running it thru a 7 stage 150gpd RODI from BRS at approx 95psi. Now I am depleting my cation media within 5 gallons but my anion and mixed bed have no depletion color change. Any help or suggestions would be greatly appreciated.

 

[Chrisv.]

1/2 lb of food grade caustic soda to 45gals of water seems like a lot to me, but that's an arbitrary uninformed opinion.

 

[Randy Holmes-Farley Verified Community Expert]

I’d also add that some mixed beds are already skewed to more anion capacity so in a perfect balance, cation may deplete first.

how did you decide how much carbonate to add?

 

[chiplake]

I’d also add that some mixed beds are already skewed to more anion capacity so in a perfect balance, cation may deplete first.

how did you decide how much carbonate to add?

Just a trial and error formula. Should I run it just through the RO section once or twice and then back thru the DI section? The water coming out of a single run through all 7 stages smells great and is not slick feeling. No taste of "soap" in it either.