Is this over nutrient burn?!??

Ok i have 8 plants in 3 gallon buckets. Thier 3 1/2 feet tall and have been flowering for 23 days. About 9 days ago i noticed rust colored spots on 1 plant leaves, the spots are spred throughout the whole leaf. I was hoping that the plant would adjust but that didnt happen. The spots spred and got bigger on several leaves and the leaves dried to a crisp. Now the problem is effecting all the other plants. Im thinking that its nutrient burn so I started feeding only water and gave tham all a good flush. The problem effects leaves here and there from the top to the bottom of the plant. It takes about 2-4 days for the leavse to dry up after it stats. I flushed 1 day ago. I use black gold potting soil and fox farms nutrient at recomended levels. Ill try and put some pics up later but im on a ipod so any thing would be greatly apritiated. Thanks

if you want any helpful replies you'll need to post some pics. it may be nute burn but it could be a host of other things. can u get pics?

here is some more pics

i think the problem here is not an abundance of nutrients but rather a cal/mag deficiency or nute lockout do to ph. has anything recently changed in your grow area i.e more or less of a nutrient, watering sched. And are your stems green or purple? let me know! ttyl

At about the same time i noticed this problem i started them on a bloom nutrien and also started giving the plant more water every watering.im getting a soil ph tester today and my water that i used for feeding was about 6.0-6.5 i flushed them with regulare tape water with a high ph of about 8 but i dont think tgat helped.My stems all look green exept for some of the older stems look purple.

Alsow i noticed just recently that some of the white hairs are turning red look like thier burning?

upload pics of the whole plant that will help. however as far as your ph goes, between 6 and 7 is perfect.