Coco hempy bottom leaves yellowing...

This is my first grow using coco in a HB. I've got coco croutons in the rez and a mix of 60/40 coir/croutons in the rest of the bucket. This is a single plant (FMS C99) in a small grow cab. Today I noticed definite yellowing from the bottom up. In my experience, C99 is a super light feeder but I think I might be underfeeding. However, I can see slightly white tips on the new growth. The problem, to the best of my guesses, seems to be either underfeeding or that the pH isn't right.





I've only got a GH test drop kit, which seems a little tricky to read, and I've been pH the solution in to just when the yellow starts to get an orange tinge (5.8ish??).



The runoff coming out is hard to check because it's a light brown color from sitting in the coco. I just upped the nute strength and we'll see what happens...any opinions from looking at it?

buy an etekcity ph meter .01 accuracy from ebay for $20 - will need 7.0 solution and 4.0 solution (use 4.0 solution for storage). Very good investment and they work surprisingly well. Also, forget the runoff in a coco hempy, just make sure when it goes in it is 5.8-6.0

To me it looks like a slight lack of N.

Coco has the affinity to stay around 5.6 to 5.8 ph so I'm thinking that ph isn't a problem. I personally feed my coco hempys at 6.0 and the coco will pull it down a bit. Hempy's seem to preform well at the mid hydro range. Just stay away from the 5.5 and 6.5. After wk 4 ph above 6.0 is even better. Just try and keep it in the yellowish range and you'll do fine.

I've also noticed that the chunk when mixed in with the coir has a slightly higher ph affinity (5.8 to 6.0 (I'm just guessing at the value here))

I only use blended coco, a brick of Botanic cocogrow and a brick of coconut mulch for my coco grows. I've never used chunk in the rez before always used perlite, so I'm very interested in how well your buckets preform.

Yes luckily we live in 2015 where digital ph meters are available, colors are kinda a opinion I think. Like " is that light orange or or yellow, well in this light...." digital meters spit the facts, untill you buy one its a total crap shoot so to speak