Flooding every 4 hours for a 1/2hour should enough for the RW-clay,if the hydrofarm is using a drip emmitter, a continous drip should be O.K,the pic looks like there is some nitro burn goin on,like i mentioned before,ease up on the nitro(about half or less of what you're giving them now)and manage the ph,when you take care of that,you'll see an improvement over several days,and dont forget to top off the reservoir with plain water....bonbon