I have a spectra pure 9 stage. Couple things I would recommend is use spectra pure products. I found they last longer especially the di. Also, I use to have my unit hooked up directly to my 110g, but It wasted so much of the filter from it being on off all the time. I now fill a 55 gallon container and use that for top off and refill that when needed. One last thing, if your having your unit hooked up to a direct line, make sure you buy a auto shut off valve. Spectra pure doesn't include one. If u don't put one on, the water will continue to run through the first 2 stages none stop.