Just wanted to chime in on the ppm run off thing.. Yeah.. 600 sound low from What I know has been done.. So just wanna make sure your getting the run off thing right. What you'll want to do is use about a half to 1 gallon of plain water (0 ppm preferred).. and water 1 cupful at a time directly into the middle of the pot. Right at and around the stem. Do this until you start to get run off. Collect a cupful and dump it out.. Don't check the ppms on the first two cups of run off.. Check it on the third cup. That should give you a more precise reading. The water in the cup that you check the ppms of should be a rusty brownish color..