Marijuana Plant Problems - Need Pro's Advice

I am having multiple problems on my plants, but they seem to contradict each other. Some signs of overwatering seen, nutrient burn and low nutrients. I know, it is confusing. Please help. Here are some questions about my setup and what I am using.

1. 2 - 400w MH Bulbs - 6 Plants
2. Flood and Drain - small rockwool inside, hydroton outside
3. H & G - Aqua A & B , root exec and drip clean
4. PH 6.0 / Hannah meter / Bluelab shows EC 1.2 - 1.4
5. Used Tap water / Pre NUT water PPM 200 / 0.4 EC
6. Sleeping Temp - 73 - 80 / Daylight Temp - 77 - 88 ( i know it gets hot )
7. Humidity - 40 - 50
8. CFM exhaust 90cfm 4x4 tray , around 6 x 6 room
9. Strains - White Widow, Wonderwoman , NL # 9 and AK48
10. 3 weeks into Vegetating , started from Seeds.
11. Have not flushed at all, but started today for 3 days.
12. 4 x 4 tray, 290gph pump 3'x's a day at 12 min flood. It takes 12 mins to fill to flood cap.

I am really confused about the problems of these plants. Some signs are showing overwatering because during sleep hours the leaves droop very bad. When the lights are on the leaves do not droop as bad, but are noticeable. Bottom fan leaves are yellow while top are still green. This is usually a sign of not enough nutrients, but I have other leaves that show nutrient burn. I have posted some pictures and if anyone knows WTF is going on please let me know. My PH is always between 5.9 - 6.2 but usually stays at 6.0 consistently. EC always 1.2 and PH is always stable. From the reservoir and bluelab meter it shows that my plants are healthy. I have a good equilibrium of EC / PPM / PH . It does not change, it stays normal . If my PH was raising or my EC was lowering it would let me know, but those 2 numbers are not moving. I am so confused. I posted some pictures and I am open to suggestions or help. Please if you know , Share some <3

Are the roots grown out well into the hydroton yet? If not I bet the issues u are seing is due to the Ph & water retention properties of RW (which I might add suck ass, unless u do drip or something controlled). Nutes seem about right to me, maybe a touch light though, by week 3 veg I am usually pushing 1.6-1.8 total (I have about .4ec tap water too). Also, make sure you are maintaining a minimum of 10 degree difference between daytime and night time temp. 3x a day in hydroton should not overwater at all though, but I see your droop. I've heard of watering 8x a day with pure hydroton. I flood 2x a day in veg and 3x a day in flower, but I mix my hydroton 50/50 with rockwool minicubes. Your nutes don't seem way low though, so look into the Ph issue, esp if you are using RW as a medium u want to drop your rez to 5.6-5.8 bc it tends to be so alkaline. Otherwise I would aim to keep it at 5.8, 6 is a little high.

Some of those white spots look like fungus. I don't think you have much to worry about as yet, they look pretty healthy. How is the airflow in the room? Does the air rustle every leaf on every plant?

deflator said:

Some of those white spots look like fungus. I don't think you have much to worry about as yet, they look pretty healthy. How is the airflow in the room? Does the air rustle every leaf on every plant?

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Update - Bottom fan leaves have all turned yellow. I was flushing for 3 days straight. New growth very green. I have adjust PH to 5.8 today and starting to up EC to 1.8 today starting at 0.4 EC. Plants are still drooping. Slowed down watering. STill Lost !!

You're low nutrients (yellowing bottom leaves), boost them, if you're coming out of flush use 1/4 to 1/2 nutrients for the first week (you don't want to shock them).

The spots are magnesium def. suppliment with 1/4 tsp epsom salt per gallon of water you use, in addition to your nutrients.

Put some air stones in your res, watering with oxygenated water will help with the drooping but if you're watering too much, it wont solve it.

-V