Well I’ve let the DI run for about 8 hours a day for three days now & I have been using the water for water changes on my African Cichlid & South American Cichlid tanks. The TDS is down to about 5 now so maybe the LFS was right about needing to flush it out really good? I figure I have run about 60 gallons through the DI so with a 4~1 waste ratio about 300 gal. total.
It could be that they use some type of preservative that affects the TDS readings but is harmless to the tank? Something like the preservative used in the Arag-Alive sand?
I still don't trust it & I placed an order for 5lbs. of DI resin from
BFS I have used their resins for a couple of years now & never needed to run any more than several gal. to get a "0" TDS reading.