I purchased a marine depot ro/Di a few months ago https://www.marinedepot.com/Marine_..._Systems-Marine_Depot-MD9113-FIRORDNH-vi.html and its been fine, but would like to upgrade I think to a flush switch or atleast order new filters.. Not really sure if I can take advantage of the BRS upgrade kits or whatever it was I saw at some point.. Anyone have any experience with it? I dont really test my TDS as often as I should But thinking if I replace the filters constantly it will be adequate.