Alrighty so it’s been a week and sadly no change....
I’ve stopped the CO2 supplementation and am just running fresh air in and out.
I added some of House and Garden’s magnesium additive and that seemed to make things worse, I only added 0.4ml/L, the instructions were 0.5ml/L.... took the EC up to 1.3 which I thought was too high.
2 days on and I flushed everything, replenishing with only the base nutrients, 0.9 EC.
The 2 largest plants have stopped growing entirely with very minimal root growth also, the 2 smaller plants are taking off very slowly but are still exhibiting damage.
I’m absolutely stumped, take a look at the photos I guess :/
I got frustrated and basically stripped one of the larger plants right back, hasn’t moved at all.
I’ve highlighted the progression of the damage, it starts with yellowing between the veins with rusty brown tips, the browning progresses very quickly until it turns WHITE, like white white.
Am I wrong in thinking this is possibly a potassium deficiency?