How often do you change RODI filters

[BuddyBonButt]

Chloramine will deplete your DI faster than chlorine.

You want to know and track TDS in THREE locations:
1. Feedwater
2. RO Water
3. DI Water

In your case it may be that the RO isn't cleaning the water as well as it should. What is your RO water TDS?

What is the water pressure reaching the membrane?

Additionally, are we talking about one of those mini RO systems here? If so, that inline carbon is not a good fit for this application, especially with chloramine.

The unit is a 100 gpd auqalife 4 stage. I don't really completely understand how they work and I don't know the ro water tds.

I used to have the needle sit at 60 psi but now it sits at 40.

This is the best info I can offer you. My tds meter only has the ability to read in two spots.

I'm not even sure which part is the RO and where that line is or where it comes from.