Good call on the TDS meter, we have 2 installed on the system here at the shop. 1 is a dual meter that shows me TDS before the filter and after the RO unit, the other is after the DI.

Today the water going in is about 120-122, before the DI 0, after the DI, still 0.

As a former hobbyist Reef Paradise is ran just a tad different then a "typical" LFS..... :D :D