AUTOPOTS YELLOW LEAVES

Hi guys
I'm running 5 auto pots under 600w hps , lemon kush
Girl S
Half way through week 2 flower

Soil , with 1.5" clay pebbles at bitten of pot
I'm using ionic soil nutes, bloom with supplements super drive , bloom booster , liquid silicon, greenmysc (I top feed on a Sunday with supplements)

Running the tank at 6.2 ph and am experiencing yellowing in the fan leaves and new growth, making the new growth seem abit thinned out on the very top,
Does anybody know of why this is happening , could it be a cal mag issue as the roots are taking straight from the water?

Mag def. usually shows on bottom leaves as mottled yellow interveinal coloring. If your only supply of cal/mag is your water, sometimes that's enough, sometimes it isn't. In tap water cal/mag is often in a large molecule form that is difficult for roots to take in. A pic might help.

just take a pic. its almost impossible to help without it. could be nitrogen deficiency for all we know. if your gonna be on the site just post pics with your problems and you will most always get a solution. good luck.

Thank you for the replies,
Il post a pic when I'm back in there

I gave them a a dose of 'grow' last night just to boost nitrogen if that was the problem

Il post a pic so you get a better insight

Just went in there and things have got worse, they weren't dropping last night?

I've took them out of there trays and have top fed them grow nutes 2/3 strength I'm going away today for two day witch is the worst case scenario!

Il higher the lights a few inches whilst I'm away just in case

Any suggestions as to what the problem is, when I seen them just then I thought it looked like over watering but they have been feeding out of their trays? There is also an inch and a half of pebbles in bitten of pots??

Humidity is 45-50%
Temp never goes over 76 f
65f lights off
Rez is ph 6.2
I tested the water in the bottom of the trays and it was 6.3 witch i wouldn't say is the problem??

Thanks everyone