just starting to have wilt and wither

3 weeks old reverse osmosis water...1/4 strength nutes feed water water...42watt cfl...fan blowing on plants...exhaust fan at ceiling level...50-60% humidity...because of reverse osmosis water is it a mag-calcium deficiency? testing water with litmus strips not sure how accurate that is...wilting leaves with discoloration...on the one plant...hate to loose it now

Adding cal/mag will certainly not hurt. Minimal dose as the plant is not showing gross signs of deficiency. Basically the plant looks good. Increase your feed to 1/2 strength next feeding and see if it helps.

Will give it a try. Thanks for your help!

Doesn't look like a calmag deficiency yet, but you will need to add calmag to RO water. Or do 50/50 tap water/RO.

Is the fan blowing directly on them at all times? In my experience, plants like oscillating fans opposed to 24/7 breeze on them.

Also I sometimes get that "claw" look if my PH is being funky. Just make sure your PH is on point as well.

Otherwise, your looking good. It should bounce back fine for you.