BluTang,
I know that, for me, the CC was my main problem. I admit I wasn't spending as much time vacuuming it as I probably should have, but once I removed it, my phosphates dropped significantly. Sometime after I got the phosphate under control, I was still having a nusance algea problem.....all over my glass a day or so after a thorough cleaning. I beefed up my clean-up crew......big time. I brought my total snail population to around 40 and my hermits to about 30. I also added a Prism protein skimmer......not expensive but pretty efective. I have no algea problem any more.
I'm not familiar with the water purifier you've mentioned. I bought a "portable" RO/DI unit that I saw on the net and is carried at PetSmart stores. It's $69.99, as I recall. Replacement filters are $20 and a filter will handle between 50 and 150 gallons depending upon how much stuff is being removed. I believe the manufacturer is AquaChem, but I'll check, if you're interested.
Jim