The tablets must have added something to your nute mix that affected EC or PH or both. Flush at once with fresh nutes and put in an airstone. These are weeds and they're tough.i put oxigen tablets in my tanks the ones you get from the pet store a friend told me to put an air stone in so like a plonker i put the tablets in thinking it would do the same thing but my next visit after i put them in which was less than 18 hours i would say 20% of the leafs were dead or dieing today is the second day and 40%are either daed or dieing its the only thing ive done so its got to be that but just wondered if anybody new for sure