Plants fading and yellowing need help here

I am running 1000 watt hps ...sunshine # 4 .. 5 gallon buckets .. been using cal mag and superthrive in light doses , my plants looked super , nice and green , thick stems , just beautiful and then they fade and yellow up on me ..been having that trouble for along time now. I have not had pmm over 250 on any watering .. mostly cal mag and super thrive ..a bit of dnf nuts but very little . I Try to keep ph from 6.2 to 6.5 using up an down if needed , got a beautful full root sysytem .. some still white , some tarnished a bit . What am i doing wrong . Last time this happened i flushed the hell out of them with plain tap water and they went down hill even quicker after that ..i'm at a loss of what to try here ... what is best to flush them with(assumng they need it) what ph water ..should i add anything like h202? will post pics..

Give it nitrogen..

i am having the same problem, you probably MAYBE , overffed them in vegetative, problems arise in flower, you flush, and then they are deprived of da green makin stuff they call nitrogen! i have EXACT same problem, flf yourushed because of a near nitrogen toxicity, where def. and over abundance almost become the same thing, and your screwed after that. in your case you in PERFECT condition to start ampin up the dosage, check ppm and ph after each watering and feeding, before and after. i have been doing that and it is working miracles, if done right you can feed them every watering while keeping your ppm's nice and low ) let me know how your problem worked out and i'de givem a little grow blend with my micro-macro(bloom_)...so add your micro, calmag,thrive alive or whatever, then your bloom, and then whatever ppm you have to work with i would do the macro(grow), so 250 ppm, eh, what do you usually work them up to in flower? im shooting for 1250 and then weenn them down in the proceeding weeks of flower..,

If your in sunshiine advanced mix #4 you need to bring your ph down to around 5.4 to 5.8. Again if this is the advanced mix you are in coco and need to treat it as hydro. I use House and Garden Coco A & B plus the Cal Mag. I really think it's your ph.

This seems to be happening to me when they get root bound ... up until then they do fine .. will try experimenting with a couple .lower ph on one ..more nitro on another maybe .. hate to kill them ..they were so thriving and beautiful its g13's sour jack!
I should also mention they are on a 24 hour light cylce //no dark period yet ..

The first pic shows the roots growing up toward the surface. It looks like they are searching for water but probably not really a problem. Mine go up some but not that much, just a minor observation, could probably handle a more thorough watering. I think they are big enough to handle more than 250 ppm's too. The plants don't look all that bad though. I don't know why people like superthrive but I never saw the need for it.

I though about that too ... when they are dried right out in the 5 gallon bucket i give them about 3 liters of water each ..some couldb be getting less ... maybe starving for water combied with starving for food is the problem..

250ppm is low but first check your ec and ph after you feed them on the run off if thats spot on up the food and some calmag and youl be cruising ,make sure when you feed you let some come out the bottom so it pushes all stale air out the bottom and draws new air in.

Repot it .

I gave a couple of them ph 5.8 with touch of super thrive..hey went to hell over night..yellowed up and spotted ...so thats not the answer ...the ones i gave light nutes to are holding thier own for now .

great read ..thanks! my water is nova scotia mountain spring water ..tests around 20 - 30 ppm ..don't think its a problem but not 100% sure.

I 've pretty much determined that the cause of my troubles was lack of water combined with lights a little to close for the dry conditions ..and not enough food . I raised the lights ..kept the water too them and up'd the ppm a bit and all seems well , have not lost any and they appear healthy !!

Ok, now they have gone the other way again ... the leaves on most are bright yellow ...small buds ... locked out look ... a handful have stayed green for some reason . I use ph up or down alot to try to keep in the 6.2 to 6.4 range ..maybe thats my trouble ..just don't know..used to be so good at this and lately can't do anything right .. ....just don't know what to try ... my water is only like 20 ppm ..my homemade ebb n gro bucket system thrived on same water ... and i mean thrived ...best turn out have ever had ..arm sized buds on the same strain . Maybe i should try a cocco mix type mixture ... ph might be more stable for me ?