Cause For Concern? Looks Like Nutrient Burn.

[wowoklol]

30-12 is 18 total gallons that the plants have fed. Make sure you're measuring the water level when it's circulated back to your holding reservoir. If you're going to fill it back to the 30 gallon level you started with you need to end up adding 18 gallons of nutrient solution. If you're filling it all the way up to 40 then you need to add 28 gallons of nutrient solution. The nutrients need to be mixed in all the water that's going into the system. This whole adding nutes in the buckets and RO in the raw or vice versa is counterproductive. Completely empty the system once a week and top off with nutrients solution as necessary.

I flushed and pumped the premixed transitional ratio nutrients into the main system a week ago. So I guess its ready for another flush and fill. I'll flush and re-fill from my 55gallon drum full of premix. Meanwhile I have the res ready to go with similar strength nutes dripping in. I didn't want to do 30gals of nutes in the res because I'd be changing the ratio in the main system and then would have to dump the res because it'd be different. It was going to take quite a while for 2 plants to drink 30 gallons. If that makes sense. Well now that its down to 12gallons, and my plants are pretty much flowering, the ratio will match the main. I think I'll keep the top off res around 15-20 gallons so I can keep it the same as whats circulating. I think we got a plan here. Thanks :D

 

[homeweed]

I just mixed nutrients into my top off at ratios recommended here: https://www.sensigarden.com/general-hydroponics-flora-series/
Then added recommended doses of armorSi, diamond nectar, rapid start, cal mag, floralicious plus, canna boost and it put the ppms up to 1880 for those 12gallons of topoff. Seemed high. I appreciate the input. I'll be adding nutrients to the top off now. Do I just use the same ratios thats in the buckets its topping off? Almost like you are saying more. If ppms are dropping. Im going to read the links posted. Ppm in the buckets/circulating is down to 390 now. Plants look great and are growing like weeds! Switching my bulb to a flowering spectrum starting tonight. Just thinking out loud.
I guess I was going off this. Which I came across early on in the process:
and:

What soil is better for cannabis growing? – helpcannabisresearch.org – How to grow medical marijuana

which both say "change nutrient solution every 7-10 days and top off with fresh water in between changes. Which as been working fine for 6-7 weeks now minus the yellowing. No anemic plants thats for sure. Not saying anyone is wrong, just remembering what I was basing my mentality off of.

For me coconut cortex is perfectly for growing where pH level in this soil is within 6.5–7, which is close to the parameter of unfertilized soil.