FLOOD AND DRAIN TIMING

Hi im new to hydro but have grown in soil for many years.
I have built a 5 pot flood and drian system with a drip and 6inch airstone under each pot .When the res floods the drip and and airstones kick in the drip only being installed as back up and for seedling stage.Im looking for a timing routine for the flood and drain i have it flooding for 10mins then draining for 20mins but im having major probs lol i have 5 nl#5 in there at the moment and they look awefull.Im also having major ph probs with it rising from 5.2 to 6.8 every day.the plants are 14 days old but man ive never had plants look this bad.could i have damaged the root system beyond repair?i just want to take clones as soon as i can from these as i dont think they would produce well after the stress they have obviously been through.Im growing with 1000 watt hps in clay pebbles and using the full canna range of nutes if any one can give a bit of help it would be greatly appreciated as hydro is starting get me down but the fear of failure is keeping me from just binning it going back to soil .

I would forget the flood and drain and stay with the drip and airstones in the rez. Are you using HPS for veg, cause that may be your problem ? They don't like HPS for veg. Get a metal halide conversion bulb to veg. 14 days should be very light on nutes also you might be burning them up. Cuttings maybe best. Don't give up on hydro, lots of good peeps here to help you tune in. Once you go hydro you will never go back to soil, that is if you get tuned in right it's great. Always give as much info as you can it gets more help. I found a drip to stabilize the ph better. What kind of water are you using ? sounds like your doing your home work.

LOC NAR thanks for the reply man .
i am using the 1000 watt mh as my ballast is switchable mate i should have put that in my prevoius post but my bulb went (sorry) i will try give you a run down on my set up.
home made hydro 5 pot flood and drain with drip and airstones under each pot .now doing away with the flood and drian and sticking to drip and airatones after ur advice.
1000 watt hps /mh switchable ballast/ditgital.
growing in clay pebbles.
water hardness 125.3 degrees.
ph 5.5 though canna recomend anything between 5.2/6.2.
nutes canna aqua vega canna ritzotonic and canna zym and aqua florres for flower with cann boost and canna pk.13/14.
water temp 70 c.

I will drop the flood and drian and stick with the drip if thats a better option .another thing that getting me is if the nute chart recomends that my ppm be 605ppm is that 605 on top of the ppm of the water or with the ppm of the water added in .The hydro shop lad advised me that i should use a product called AU 60 to to repair the roots after ph damage has this been a sales pitch as we know what hydro shop dudes are like lol or is this a good idea.the water is tap water left sitting 48 hours to get rid of the fluride.since i done a res change the plant have picked but the first set of leaves are showing sign of ph probs and lock out and i cant think why
any input would be great help.