Coco yellowing new growth Please Help

Alright so i have a problem and i could really use your help. I have 8 clones in roots organic coco being fed 1/2 gallon every other day which gets the desired 20% runoff. i use 7.5 ml house and garden a/b and 10 ml a gallon rhizotonic. They were transplanted 4 days ago and this yellow has started since. The ph has been 5.8 every watering and i used my tds meter once to measure the tap water i use and it said it was at 400 but i went out and got tds calibration solution which is 1300 ppm and my meter read it at 2600 so i am guessing my tap is around 200. i run the tap water through a small boy declorinator. The enviroment is in perfect condition with good intake from fresh air and outtake. The plants have been under a 400watt hps but i just switched to mh today. temp is in the 70's lights on and 60's at night. It looks to me like iron deficiency but i could be wrong. Do you guys think i should supplement with calmag or should i use something else. please help. thanks.

I think i figured out the problem. i was following the house and garden directions and said that add a/b then ph then add your additives. i was adding rhizotonic after i ph'd. i read that rhizotonic has a high ph and it must be spiking my ph. I guess i am running high ph and it must be locking out my micronutrients. I flushed and ph'd after everything. does this seem right. how long do you think until i see some improvement. anyone have any idea?

Over 100 views and nobody has an answer?

Check your runoff of your plants water and if its any other number than 5.6-6.5 you should get some dolomitic lime and do a top dress to first correct ph issues. looks like newer growth is yellowing and is most likely is an iron def, cal mag +at 10ml feedings until problem starts to correct and then drop back to 5ml/gal

Are you using extra cal-mag? I've been told that coco loves to sap the cal-mag from your nute solution. Most cal-mag's have Iron and/or Boron in them so that should possibly help even things out... I also agree about your pH, pH is crucial.

no i havent been adding any calmag because i figured my water was hard enough. but i guess i will add 10 ml per gallon next feed and see if they improve at all. i havent seen much of an improvement since i flushed with correct ph adjusted water. any idea how long it should be til i see an improvement.

How long till you see improvement? It depends how far into the deficiency the plants are... I'd guess a few feedings. Are you using a FEED, WATER, WATER schedule? Plants, all plants, love fresh water. And by fresh water I would still add cal-mag until you see improvement. Hope that helps with salt build-up too. Good Luck!