have you started feeding them yet as it looks like a N deficiency if you havent started feeding i would start them of with something light around ppm 300 as ak likes its nutes ,Dutchmasters nutes are ok its down to preference really and with you being a aussie dutch masters are made there i thinklol im a scot no one makes them here lol do you have any superthive? sorry for all the questions but im not on for long and would like to catch you before i go off line but if i dont just leave the answers and im sure someone will help out if not i will be back on line later.best of luck and hope it all goes well as ak is one kick ass smoke.daveyboy the postman.