Keep trying to find when to change solution, during dark hours? Just restarted second grow first was sort of failure but informative. Know isnt suppose to have light penetrating tote
What do you mean by change solution?
Replacing whole nutrient solution out of DWC tote with fresh.
Should I also be checking ppms & tds when lights are off?
I think i would do it at lights on. The light on plant during lights out will be more detrimental than light on the solution for a short time.
But i dont do dwc so that’s my 2 cents and may not be helpful