Clones in Rockwool

[Headsmcgee1]

R/O filtered water
Rockwool cubes

I'm getting a slight burning on the tips of my clones that about to root. I assume that is from the Ec/ppm being basically 0. Any suggestion on what I should use to raise the ec/ppm that is good for these clones?

 

[gaiusmarius]

are there roots sticking out of the cubes?

if no roots i advise plain water with ph 6.0 till roots show. only water if the cubes getting dry.

if there are roots visible then you need to give a low dose of nutrients, ec 1.0 or close.

if there are bugs treat the bugs.

to me it looks like clones that didnt quite make it to roots as fast as their mates. maybe shaded or too crowded. but they normally do root in the end, if they don't just die anyway, lol.

best of luck.