Strawberry Cough in bubbleponic SCROG

12/2 - Noticed some nutrient burn and possible minor calcium deficiency within the lowest fan leaves of 3 plants following the latest nutrient and water tank top up. Reduced the EC from 1.6 down to 1.4 and added a slight top up of CalMag in the water. Seems to have stopped the spread and the plants continue to grow astonishingly quickly compared to my previous experience working with soil. That said - apart from the recent minor hiccup - the nutrient solution has been seemingly perfect for me throughout the past 3 week. The plants are drinking, but the PH is only gradually increasing by about 0.1 over the course of a week, and the EC levels have remained basically static. I plan to fully replace the nutrient solution in the next 7 days for a fresh tank, and will do so every 2-3 weeks thereafter (or sooner if I'm topping up more than expected!). Performed some LST today to open up the canopy on the most advanced of the four plants. I expect to follow up in the next 48 hours on the remaining three, and to put in place a SCROG net within the next 7-10 days - I am waiting for the canopy height to increase enough that I can easily access underneath the back two plants (if needed for pruning etc.) from the side doors of the tent once the SCROG net is in place. Edit: In retrospect I believe it was light burn rather than nutrient burn or a calcium deficiency - I only noticed that my lights were 6 inches lower than I thought when I installed the SCROG screen in week four. I have already made a couple of slight amendments to my Wilma/Origin system by drilling additional drainage holes under the pot to prevent them from being clogged by roots at a later date. I am continuing to make minor adjustments to my new setup as I go, including; replacing the original MJ500 pump with an MJ1000 for higher water pressure; replacing the black pipes with white insulated ones for lower water temperatures; adding an additional shut-off valve to prevent minor unwanted watering during nutrient mixing; and potentially adding an additional four drippers for greater coverage in each pot. Additionally, I have purchased all the items needed to make my own SCROG frame for the tent using 25mm PVC pipes and 2mm paracord, as I do not have faith in the elasticated net that I already have to either stay in the correct place nor support the plant when it's in full bloom. I've bought spare Secret Jardin space booster parts to hopefully create a very clever attachment system to my tent frame, so stay tuned for this next week. I've also ordered a mycelium CO2 bag and CO2 meter, simply for the scientist in me to see if they actually work! However, I don't expect either to arrive/be in working condition before I flip to 12/12 in a few weeks.