I think the tds meter had tds and temp on it. I asked the guy at the hydro store about an EC meter and he said I really didnt need it but that the tds meter was vital. The neuts I use now all botanicare products. They will work just have to modify recipe to get correct ppm's right? I have been using pro bloom, liquid k, hydroplex, and bud candy. I will switch to RO water and get the cal mag and B-1 will I need anything else? Thank you so much for taking the time to help me. I don't really consider myself stupid but sometimes this stuff gets so overwhelming it makes you fell that way as well as having a very steep learning curve. LOL