Here is a food link
Calmag also help a stabilise the ph in the medium
www.canna-uk.com
You seem to know your sruff Maybe more then me ;)
Hermie is not good hopfully want
Is that pump waterfalling to get new air in they res? They will make it smell or water temo to hot?
68-70f is good
Maybe try power ph 5mset 5.8 Leave drift to 6.2 and reset I aim for 5.8-6 some say 6-6.2 and some say late flower 6-6.2 for different nutrients uptake,
Thats all I can help you with lol let me know how that
calmag goes
Off to bed now chow for now