With your 14 TDS coming out of the membrane you are going to use up DI resin quicker. I would look at replacing your di with something like this.
With the dual DI the first one is a roughing stage and then the second one is a polish stage.
The lower you can get the TDS out of the membrane the longer your DI will last. If you could get your 14 down to 7 that would double the life of the DI resin.
SpectraPure® MaxCap® System Add-Ons
SpectraPure® MaxCap® D1 Single-Stage DI System Add-On Install a MaxCap® DI cartridge ahead of your existing DI cartridge. Includes clear filter housing, quick-connect fittings, mounting bracket, High Capacity MaxCap® DI cartridge, dual-probe TDS monitor, & filter wrench. Single DI Addon that can...
spectrapure.com
With the dual DI the first one is a roughing stage and then the second one is a polish stage.
The lower you can get the TDS out of the membrane the longer your DI will last. If you could get your 14 down to 7 that would double the life of the DI resin.