wow, cheers for all that info guys..
there is a difference between the ph in and the ph out, its usually quite considerable. The nutes go in at 5.3-5.8 (vary each time) and the runoff is from 6.2-6.7
I feed at quite a low ppm (600-900) which stays the same in the run off.
I am not sure why the PH climbs
I have to water every other day at the moment, usually the reservoir will have some in it, but the buckets feel substantially lighter.
Should I be watering every day to keep it topped up? Or let it dry out more often?
thanks again..
I would agree with Watt that they seem to look like they are just aging, but it could possibly be a ph problem.
I had similar problems with my last grow. I was running my ph at 5.5-5.8, and they were yellowing pretty bad and looking like they were starting a N def. I bumped the ph up and they really responded. My ph "goldilocks" zone is now 6.0-6.3 and I haven't had problems since.
I run str8 perlite buckets also and just based on my own experience a ph slightly above 6 seems right for them. I always consider hempy to more closely resemble a soil grow than a hydro. I also let my buckets dry out real good and I also flush periodically throughout the grow. I think that the drying out and flushing helps alot with nute uptake.
Just my couple thoughts.
Edit: The ph jump you are getting might be due to excess salt in the medium. Do you water with a good 20-40% runoff? I would flush with a clearing agent or if you don't have one a weak nute mix of about 100-200ppm followed by ph'ed water 2x the bucket volume. I have 1.25g buckets and I hit them with 1/2 gallon of clearex followed by 1 gallon of water, but I flush regularly so in your case I would increase the volume of water when you flush.