I feel like this question has been asked 1000x but can't find an answer specific. We just moved to Louisiana, I have a BRS 150gpd 5 stage unit. Brand new RO membranes, pre filter, carbon block, and 2 DI canisters. I use a pump so I get about 90 psi. Basically both DI canisters were exhausted after filling my aquarium for the 1st time (170 gallons). TDS going in:115....TDS after RO:4....and zero after DI for about the first 150 gallons. Then it read 1-3. The di is exhausted and the carbon block is looking rough(little brown spots on outside of filter). My question is could this be chlorine ripping through the filters? If so should I run 1 pre filter, 2 carbon blocks and one DI? I really appreciate it.

And the ladies are pretty good at looking at test strip colors while we just stand there looking, and looking and can't decide what shade of blue the sample is. LOL

