40 days into flower - Fan leaves are burning on the ends? Normal?

[tozort]

Hi ...the leaves on 3 of the strains are yellowing and falling off,The Indica strain is green but now are starting to yellow some..All have great buds and hairs are growing to the lights..trichomes are still clear and look great,I give a full strength feeding for the first time last week...cal/mg,and bloom ,general hydroponics ...I have always gone water/feed with nuits/water/ect.so i was waiting for this..Tips burning is nitrogen,but 40 days into flower,Is this normal? anyway,,the only thing i have done is started to flush... straight water...then i will feed 3/4 strength,water/nuits/till I see amber,then what..no water for a few days? or harvest then? Or is there something I should do? ..Thanks for your time..So again...tips a burning..new growth looks good.but fan leaves on buds have tips burning,Is this normal?40 days into flower?..

 

[tozort]

Thank you....I sould have backed off the Bloom, with the cal/mag...I know better...Anyhoo after 2 gals strait water they look great...next feeding half on the bloom3/4 on the cal/ mag....Or I might go strait water one more time...I don't want them to wet...so after the flush...There getting nothing for 48 hours...Thank you...the buds look fine...