I've just come off fixing my ph from swinging WAY too high in a short time (it was not normal ph drift). I replaced the water and flushed, things seemed good until a few days later. Now my ph is slowly drifting down from 6 to 5.5 in the course of half a day. The plants are getting worse. It started out as ph spotting, but grew into mg, cal, or phosphorus deficiency (I strongly believe it is the mg that is locked out and they are also a little K deficient in parts, yellowing has occured as well but that came with the spotting). The scary thing is that the runnoff from my buckets when the water is running (the whole light cycle for hydro) is coming out a full (.1) lower than what is in the rez? What is causing this to happen? I have six 5 gallons buckets with hydroton in a recirculating drip system with a 15 gallon reservoir. I use ice to keep the rezzy around 70. Two 400 Watts I use RO water with 1 tsp per gallon of calmag, some potassium silicate, advanced nutrients micro, grow, bloom, a little supervit, and some compost tea/sweet. Would someone give me reccomended amounts for say 10 gallons of these ingredients? I have changed the water, twice, and done a MASSIVE FLUSH with RO water and clearex. However, the ph is still coming down. I WANT TO FIND OUT WHAT IS CAUSING THIS: MY THOUGHTS: 1. I read somewhere that there is an excessive amount of K uptake in the transition week. Could this be causing my ph to drop? 2. Root rot? I dig down enough to see the roots and they look totally healthy. Still I added some DM ZONE (same purpose as H2O2) to kill all the bacteria, rot, etc. but I am still having the problem. 3. Too low ppm? I used to do dwc. Then each plant got 3 gallons and roughly six tsp's total of the Advanced 3 part formula, but now that they are all on the same reservoir I am worried that I am not adding enough. My ppm's are anywhere from 600-700ppm. I am pretty sure these don't have anything to do with it: incompatibility of nutes and additives, evaporation (I lose some water, but I don't think that could cause as much flux as I am seeing), or my reservoir being too small. Any help is appreciated as I have called the tech support at advanced and local hydro stores and even they have no idea what is going on. Ph should be rising!!!