Hi Weedhound. No I only have a TDS meter, but isn't it just math to determine Ec?

I believe most tap water has ph buffers. Also, before I had my RO filter and used only tap water, the ph was always high and it took quite a bit more ph down to bring it down. With RO water, it'd only take 2 drops where it used to take 10mls. Thats the buffering capacity in action.

I did some reading on icmag forums, and there is a nice thread about water including PH and buffering capacities and such and such. If I add sodium bicarbonate (NaHCO3), (baking soda! lol) it should increase the buffering capacity without increasing the waters hardness. But I'm leary of trying it, and leaning more towards simply including some of my higher ph tap water first.

I peeked at my roots today and noticed some roots heading into my drain pipe. I gently fished out about a foot long group of roots, lol. I had visions of waking up one fine morning and my entire room is flooded, circuits blown etc etc. Gonna have to rig a barrier that blocks roots, but allows water to flow freely... yikes.