please help me, ive described my setup as best i can, ive spent hours looking at posts on here and i still cant tell what is wrong with my plants

-indoor grow
-soil
-vitamix soil
-nothing added to the soil
-Soil pH = 6.5
-Water source = tap water
-Water pH = 6.5
-Age of plant = 4 weeks
-Type of fertilizer = biobizz's bio grow
-Rate of application = currently 1,5ml per litre
-Lighting source = 600w HPS
- Distance from plant = now 20 inch, was 17 inches for last day or two as plants grew and lights werent adjusted
-Temperature 27 - 30
-36% humidity. (Maybe due to no watering yesterday and not enough watering the day before, both the plants and soil were bone dry.
-Lighting schedule = on 24 hours
-Ventilation = none as yet, shed door is opened once a day for 20 mins and is larger than a spare room.



I had bad yellowing of lower leaves on 3 plants starting 2 days ago but at same time the rest of the same plants were a deep green, all of my plants leaves were droopybut looked healthy. So I thought id tackle the droopyness first and thought they may be overwatered so i never watered them at all yesterday, this morning they where all withering and they looked as though they were nearly dead. I immediately watered very generously, more than double what I normally would, I watered with just water no fertilizer added just in case, but I did add half a tea spoon of epsom salts to a gallon of water to tackle the yellowing.
Half an hour later the plants already looked better from the watering but I think I will loose quite a few leaves if not plants, cant believe that they changed so dramatically.

After the no watering incident all the plants have seemingly slightly different conditions???
Before that just 3 plants had blotches on the lower leaves spreading from the middles but not on the green veins, thatâ??s what made me think it was magnesium deficiency.


Heres some photos fo the sickest ones, the yellow and droopyness of the leaves was present before thebad watering experience but the curling down and up of the tips are just on two plants and hasve newly appeared today, im gutted
Yellow blotches
http://www.freefilehosting.co.uk/fil...y%20leaves.jpg

saggy as hell, also yellowing and dry
http://www.freefilehosting.co.uk/fil...llo%20leaf.jpg

same plant, worst leaf
http://www.freefilehosting.co.uk/fil...ing%20leaf.jpg

same pic different lighting
http://www.freefilehosting.co.uk/fil...low%20leaf.jpg

Saggy!
http://www.freefilehosting.co.uk/files/1427/saggy.jpg


Turned up tips??
http://www.freefilehosting.co.uk/fil...0up%20tips.jpg

Turned down tips??
http://www.freefilehosting.co.uk/fil...own%20tips.jpg

Different ailment maybe? as on end of leaf?
http://www.freefilehosting.co.uk/fil...g%20leaves.jpg

Yellow blotches
http://www.freefilehosting.co.uk/fil...es%20close.jpg

Please help them!
smackhead1984 Reviewed by smackhead1984 on . Please help them theyre dying! please help me, ive described my setup as best i can, ive spent hours looking at posts on here and i still cant tell what is wrong with my plants :( -indoor grow -soil -vitamix soil -nothing added to the soil -Soil pH = 6.5 -Water source = tap water -Water pH = 6.5 -Age of plant = 4 weeks Rating: 5