Tip burned??? but only on VERY FEW leaves

a few things can cause this symptom and lockout can cause them all (but usually has more than 1 thing showing if it is ph-caused) even a deficiency can cause it, so no guarantee it is a toxicity either. Get a leaf symptom chart... start memorizing it and the logic... e.g. understanding difference of symptom progression of mobile vs immobile nutes can help you distinguish problems. above all, if you don't know what you give it... it's a total stab in the dark... know what you feed and you can diagnose problems with the snap of your fingers instead of guessing. it's not magic. everything works in a consistent and predictable fashion. SO, Your plants look healthy, that's a good thing. The problem seems slow-moving, another good thing. It won't take a drastic change to fix whatever is going wrong, so be patient and read the plant.. don't assume things. some clawing, but good color all over... look for any purple streaks in stem (not petioles) to rule out S-deficiency. if that's good, maybe a 5-10% reduction in what you are feeding and see what happens? you could also wait a bit and see how it progresses. if you recently started boosting P, it could be from that, but i don't see typical coinciding symptoms. underwatering? even in soil you want *some* runoff without getting wild. dry pockets are ripe for salt buildup.. can be sneaky and take a long time to show itself (or quickly in more extreme cases). Don't try to feed a specific volume of water... you water until you get a little runoff... if the weight of the put is the same each time you start this process, it will use roughly the same volume of water -- if you want to plan how much fertilizer to mix. if you use similar soil/substrate components and proportions, this will be something you can bank on in future too. if/when the soil is sapped and you are providing near 100% of nute needs, start religiously getting 10-15% runoff waste water -- toss it outside or down the drain, don't let plant sit in it. This will virtually guarantee there is no salt buildup. as always, good idea to check your pH ... runoffs and soil slurries are not the actual pH of your substrate... more of an art than a science interpretting that stuff.. be consistent in how you do it -- e.g. a slury should be same pH water to start and same volume... and always use same volume of substrate when mixing... the resulting pH will be a weighted average of the components invovled... if you stay consistnent, the readings will make more sense with more experience as far as whether you should react to it. *i doubt this is pH-caused...