Need Help, sick plant and when to start fushing

[elite]

hi,
so im growing 3 akr and 3 pineapple express in a hydro system with 400w hps, went for nft type feed system on about day 60 now and 1 of the pineapples seems pretty sick but think its about time too start flushing her so dont know what to do really :s, was thinking of pulling it out of the hydro system and planting it in a gallon pot with them clay pebbles around the root mass and rockwool it was planted in with a dip system too feed it and try fix its defficency and then start flushing it ?,
this is my first grow tho so when i started i didnt account for alot of things i should have but atleast il know more next time round
so here are the pics of the pineapple in question.
res is about 25l and i change it every 2 weeks but i dont add nutes between changes is this wrong and possiably the cause of my troubles ?
View attachment 146945
View attachment 146944

 

[alley_walker]

As harvest comes closer, the leaves turn yellow and die.. Autos are known for this.. Pine Apple Chunk it's gene pool is really known for this! If it is some sort of deficiency I would blame a lack of mag.. But looking at the buds, it's really to late to do much about it. Take a close look at your tri-cromes and see what color they are. Amber? Chop the lady..

 

[elite]

cool thanks for the reply man, went and bought some plant magic flushing stuff today so ill start flushing for 10days then chop her up id say