well since I wrote that the last plant in the system has started to wilt :/ increased the pH to 6.2 but I think if that is the reason it maybe to late for them anyway.

That one has recovered, so yes a to low pH will cause them to wilt without any other signs of nutrient deficiency. Problem is that being sick it now has early blight, but at least I will get a havest from it.

Well, as you discovered, that low of pH will damage plants. It can damage roots. It inhibits nutrient uptake. It will inhibit transpiration (thus causing wilting). Are you sure the plants have early blight? They could just be suffering from deficiency and may recover. I mean, with that low of pH, they will suffer nearly every deficiency possible as the minerals become unavailable. I think the only mineral that would be more available is iron. It's a quirky one, that iron.

at 3.2 you're probably burning the roots. I wouldn't want to stick my hands in it.

haha 3.2 isn't so bad, about vinegar levels. I think I spoke to soon though, while it is still alive and doesn't seem to be getting any worse the tops are wilting again.

joe.jr317 deffinately early blight, my sungolds seem to get it every year anyway... brown bullseye pattern with a yellow halo.

I really don't know how my pH got that low anyway, tap water here always sways on the alkaline site, the island is a limestone rock.

It seems the subject has change a bit since I last checked, but FWIW -

Check out what the professionals are doing:
http://www.cornellcea.com/handbook_home.htm

Cornell has put out a few hydroponic grow handbooks, and they're definitely worth taking a look at. They use rafts to grow their lettuce, too. The lettuce book states PPMs, light regimens, and PH.

The PH and ppms are in normal units, but the light regimen is in Mol/day (17 if I remember). I did some research in how to translate this to watts, and I figured this equates to 7, 4' fluorescent bulbs per meter squared on an 18/6 cycle. That's roughly 25 watts per square foot. That's pretty modest if you ask me. Of course Cornell is running CO2, temp controls, and pure O2 bubbling into the water, so maybe Cornell's light regimen doesn't translate into a home grow.

What? I can't tell if that is spam or a misunderstanding. Cornell is a good resource, but not sure where Blendie was going with that.

Yeah, the 3.2 won't hurt you if you don't keep your hands immersed unless you are really sensitive to acidity. My daughter is. Tomato juice irritates her skin. Sucks. She loves tomatoes so she just deals with a red ring around her mouth for a couple hours when she eats. My mom can't even handle them or her eczema flares up.