DAMMIT !!! ive just ben reading a thread on Pythium.

Early stages..Yellowed, droopy and wilting leaves (possibly exhibiting mineral deficiencies). Leaf curl over - ram's horns' - roots are unable to uptake nutrients at that strength because they are infected.

pH becomes more acidic (pH should rise slowly in a healthy system)

My ph DID drop to around 4.6

Reduced water consumption, slow/stunted growth, roots a bit dirty looking..

DAMMIT DAMMIT DAMMIT...its all making sense now.
I said the problems all came on sudenly without me making any environment, system or nutrient changes..same mother plant..which is fine..

Im not the most sterile of growers, who is ? My reservoirs are comming up for 2 years old. After one crop i remember leaving the root ball in the idle nutrient tank for abnout a week, until it smelt that bad I HAD to throw it out..and i dont think i have sterelized the tank..EVER ???

Be clean kiddies...or this could happen to you.

I think it might be time for a Hydrogen Peroxide root dunk !!!

And a sterelizing mission ???