Is there any difference between RO water at 0 TDS and RODI water at 0 TDS? I run my water filter system and found that my RO comes out at 0 TDS already. Do I "get" any advantage with the DI if it's already at 0?
If / when the readings start moving above 0, that should mean it's time to change the pre-filters? or start flowing to the DI and check and see if that moves above 0.
My input reads are in the 130's TDS range.
I only run a RO unit, my tds are about 10ppm and it feeds 2 tanks, a 125 gal fowlr w/55 gal sump and a 75 gal mixed reef w/55 gal sump and my tanks are AWESOME... no issues.. oh, in the fowlr I run a VERY heavy bio load and I tend to over feed..and to be honest, there is probly a heavy bio load on the 75 as well...
Right, the cleaner the source water the longer the filter cartridges will last. I also replace sediment and carbon every 6 months. The DI is replaced once I detect TDS over 1. RO is every few years depending on how it's working.
Fortunately, the RO membrane... which happens to be the most expensive component... should last about 3 years. It depends on your filter change routine, and if you use a flush kit. Dirty or leaking filters and no flush kit will kill the RO in short order.
My neighborhood has a community well and we have hard water at a 17 grain and my TDS before my softener is about 470 tds and after my DI it is 0. I havent checked what it is after my RO membrane...I need to hook up the meter to it. I know I had to replace my DI resin after the first 50 gallons. I added a 2nd DI chamber now. Thats the beauty of the RO units....you can upgrade them super easy and pretty cheap. My unit cost me $85 on eBay for a 4 stage and I added the 5th stage for $22.