- Joined
- Oct 6, 2018
- Messages
- 80
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- 26
How do I know when to change carbon filter, ro membrane, and di cartridge? I have a used spectrapure with dual ro membranes in series. I have an inline tds meter. After the dual RO stage it reads 9 and after the DI stage it reads 8. The carbon and sediment filters haven't been changed for quite awhile and are pretty nasty so I'm wondering if that's reducing the ability of the ro and the di stage or if the ro membranes and DI cartridge also need changed. I bought it used.