Hello, been growing in hydro for years never had this problem before and can't see to find a solution. Top of leafs and heads are turning yellow then white. Current culture systems Room temp is 78 Water temp 68-71 Ph 5.8-6.5 Food is cultured soulutions for base and botanicare for calmag Using de agrolux ballast with de mh solstech bulb Lights 5 feet+ above plants Sealed rooms Co2 between 900-1100 This is happening in all systems, called current culture they said could be a bactira in system so killed everything let system soak in bleach disinfected rooms and all equipment problem came back on new plants. Tried to change food to canna didn't help, tried to change botanicare calmag to the an calmag didn't help, tried to add a RO system to water filters didn't help, tried a new genetic from different sourc still problem keeps coming back. Check ph everyday if it is not in range empty the system adjust it and pump it back in. It looks like iron deficiency so been doing a daily spray of calmag plus and advanced nutrients revive still not helping . Tried to also top pour all plants with a revive mix still noting also tried a daily spray with power pack from hydrotech and didn't help. Really need help this will be 4th time having to kill plants beacuse it just continues to get worst thank for for your help.