I’m doing something wrong

I’m doing something wrong. I’ve noticed the leaves are drooping and lower leaves are almost blistery. The tips of some of my leaves are burnt. Growth seems stunted.
I have had 4 harvests in the past with 2 plants per harvest and every plant I’ve grown has had this problem, but never seems problem enough to kill the plants. I would like to see if I can write down everything I do and see if someone can catch the issue.

Strains are: are headband (fem) by pristine and evere5t (reg) from erbaceous.
Both about 2 months into veg
Light schedule: 18/6
Lights: 200 watt LED. 3500k
Grow medium: coco coir (50%coco and 50%perlite)
Fabric pots
Drain to waste.
Temperature: 23C day and 18C night(73F to 64F)
RH: 54%day 65% night
Well ventilated grow tent with small circulation fan

Watering: they currently get watered 3x a day automatically. At lights on, 7 hrs later, 7hrs later(my past grows they were watered 6x a day, every 4 hrs. Reduced watering in half to try to solve above issues). There is always at least 20% runoff, no more than 50%.

Water: R/O water used, currently ph is 6.2 with nutes added (past grows ph was 5.9, tried to raise ph to fix above problems)

Nutes: GH flora series. For veg plants I am using calimagic(cal mag), micro, grow, bloom, diamond nectar (Humic acids) (added to water in that order followed by h2o2 and ph up)
I use their expert program for drain to waste. My past grows I have used half of recommend doses. To try to rule out nute burn for this grow I am using 1/4 of recommended doses.
What they say I should be using is (in ml per gallon)
2.5 ml calmag
5ml micro
5ml grow
2.5ml bloom
5ml diamond nectar
I have been adding those numbers to 4 gallons instead of 1 to dilute by 1/4.
PH is 6.2 (have also tried 5.9)
tDS is 266

Runoff water tested at 80ppm tds but the container has algae in it.

plants are on little stands inside the kitty litter bins.

pictures were taken while the lights were supposed to be off


Please help

Algae will choke off and kill your roots, which kills the plant. 266 tds sound pretty low. Using 4g for ferts instead of one isn't reduction by 1/4. It's reduction by 4X, four times the reduction. I guess you mean dilute TO 1/4. If you want to reduce from current or full amount previously used, only use 2 gallons, or 3 when they're small, then get up to where you want by reducing the dilution, is my suggestion. Usually 400-500ppm is for starters but not sure about tds. mature plant pics look pretty good. No light leaks as that will allow algae. Should sterilize or replace everything and stop any light leaks to the water.

Whenever I get those leathery looking leaves I cut back on watering and it rights itself.
Which for me means cutting back on nutes because I feed every watering.
So it could be just a little of both.
Plants don’t look bad at all.

if the tds is low, cutting back on water/nute mix isn't a good idea. you have to determine if the tds is too low first. leaves look pretty good however on mature plants. ok it seems oddly enough. obvious algae is a problem.

Plants don’t look deficient in any way.
My inclination would be the same as the OP.
Cut back on the water.

Straight coco/perlite? Fuck. I’m not sure now.
Better listen to the coco guys.

Thanks for the replies! The algae grows in the wastewater bin that I vacuum out because of the light. My plants don’t sit in the algae water though. The reservoir and lines are clean and there’s slight algae on the top of the soil of the seedling. I just think the waste water tested low ppm because of the algae in the waste bucket

Also, these plants have always had the same concentration of nutes( diluted to 1/4 recommended) but on different grows I’ve used 1/2 recommended and had the same problems

Sometimes cold temps can give leaves that appearance as well.
Wish I could help you more. I’m a soil grower.
But as I mentioned, less water (and subsequently less nutes) has fixed that issue for me.
Good luck.
Your plants will produce. They look good.

Part of me was thinking it was a temp issue. I considered at one point looking into a silica supplement

My plants do fine at 64° for the low and they spend most nights of the year at that temp.
Except for deep Summer.
But you never know. Different strains.