Ok All, I'm having a difficult time figuring out how to know what to add as far as nutrients are concerned. I have a TDS / PPM Meter & my Tap Water reads 185 on the PPM & the temp 24 Celcius ( not sure what that is in degrees). My pH tester I have to hold the Cal button down to get a reading at all or it goes all over the place. Is it suppose to work like this ? I bought someone's equipment & got no instructions on how to use any of it. When I hold the Cal button I get a reading of 686....I'm guessing it means 6.86 ??? I've been using a 30-10-10 Fertilizer about every 4th watering & only watering about 5 times every 2 weeks. My plants are now in 6.5 Gallon Pots so I use about a 1/2 gallon each watering on each plant. Anyways some of the lower leaves are getting yellow & there's yellowing at some of the tips higher up. A few of the lower leaves have died off & I'm noticing some yellowing in the leaf veins. The Fertilizer is 30-10-10 (it's 3% Ammoniacal & 27% Urea Nitrogen / 10% Phosphate / 10% Soluble Potash ) (.02% Boron / .07% Copper / .325% Iron / .05% Manganese / .07% Zinc). I grow 4-Plants in a 2x4x6 Tent with a 400 Watt MH Tube Light & 2-45 Watt LED side lights. I use a Carbon Filter & Fan. My lighting is cooled by 2-6" inline fans & my tent is cooled by a small home Humidifier & a Clip on 6" fan. My tent temps with lights on have reached 84 degrees but usually stay closer to 80 - 82 degrees with 40% - 60% Humidity (Daytime). With lights off temp drops to about 75 degrees (night time). Next grow...lights at night & dark during day as I'm in AZ. & houses get too hot when summer comes. Hard to cool a house when it's 120 degrees outside. Anyways, I was thinking about switching my nutrients to the Flora Series (Flora Micro / Flora Grow / Flora Bloom & adding CaliMagic. Is this a Good idea or a NO ??? OK....you know what I got & what my problems are so any & all help is deeply appreciated. I have too much invested to lose these plants (already 2' tall or more & 3-4 weeks away from Flower stage). Please Help if you can .....Thanks !!!