What is your TDS reading before and after RO and DI

[350gt]

I replace di every 3 or 4 months, doing 30 gallon water changes every 2 weeks or so and topping off about 10 gallons a week.


Readings are about 227 in, 3-5 RO and 0 out.... I know the carbon and sediment need replacing when the RO gets over 7.

Do you let RO rinse for awhile being producing DI water? The RO when first turned on will climb as high as 100+ and will drop to 3-5, thats when i open the valve to the DI... If not you're killing your DI prematurely..