hydroton and PH
I'm using some hydroton in a flood/drain that's been sitting in the closet for a few years. I washed,rinsed, and let it soak in ph 5 overnight. Last time it was in use I remember having no ph problems at all. Now, I'm going from tap H2O at 8, adjusted to 5, and back up to 8 overnight. First, I blamed the tap water but after mixing up gallon and letting it sit out overnight I'm back to blaming the hydroton. I left half sit in a small bowl and the other half in a larger bowl filled with hydroton. The water only half is steady at 6, but the hydroton mix is up over 7. I'm leaning towards bacteria/fungus even though there aren't any visible signs. Any other ideas? I've read a lot about washing/sterilizing but don't really know where to go. H2O2 or bleach? What ratio? Bake in the oven or microwave? Has anyone overcome a similar situation?
I'm testing ph with liquid, i've lost faith in my meter. Although the plants don't mind (just harvested a great crop of romas and chiles), I'm losing sleep not being able to get a handle on this.
thanks in advance for your help.