ceg4048 said:
K+ shortages does not typically show up as yellowing. That's usually an N or Fe or Mg/Mn issue.
I believe you. I find those schematic diagrams with plant symptoms of nutrient shortages very ambiguous. I just though it were K+ cause I know all the remaining are dosed in excess. Only K could be in shortage as explained in the post above.
ceg4048 said:
Also, it is not necessarily so that just because you add 6ppm on day one that all 6ppm get used up by day two. Uptake rates depend on a lot of things such as PAR, CO2 and so forth.
Very true and I do not know my consumption rates cause I haven't make any test yet
😀 However I do know that I have lots of CO2, very good distribution and moderate light so I assume that I have moderate consumption rates and again, lost of plant mass. It's just that K+ is the only one that is closest to its lower boundary level (according to EI).
ceg4048 said:
Did you really pay £40 for a bottle of ferts? I mean, if you wanted more K couldn't you have just added more KNO3, which is 40% by weight in K??? In any case since we don't really know what's in this K40 there is a possiblility at least, that it contains other macronutrients or micronutrients, and that those would have been responsible for the improvement. If you wanted to vefify that it was a K deficiency you would have to use a K salt alone that would not have any other components whose deficiencies are not implicated in chlorosis, such as KCl or KCO3. They don't really say how they derive their K, and they don't list their ingredients, which always makes me suspicious.
I did not
😳 . I was given by Felipe Oliveira (FAAO) after a workshop I attended. Never had used it before cause I use dry salts.
😀
I know I could just up my dose, but I was suspicious it could be a shortage of K+ and so added the K40 from Elos. Otherwise I would be mixing NO3 and PO4 as well (cause I' using a liquid mixture) and would never be able to distinguish whether it was a K+ shortage, NO3 shortage or whatever...
You're right. They do not give us the composition. But I assume that at least K+ is the main thing in this K40 from Elos. It was the closest I could use without the need to buy more dry salts (e.g. KCL).
Anyways, this is my experience. I know what I did was not scientifically sound (I know belive me, I'm an experimental marine ecologist). But given that: (i) Jame's recipe is generally low in K+ and, (ii) since adding K40 (even with all the doubts about its composition) plants improved in colour - there is anecdotal evidence that it was, in fact, a shortage K+, IMO.
Going back to the topic (sorry for hijacking your post skankypup), I thinkg that you are in the right path by raising you CO2 levels, starting CO2 injection earlier and by spot-dosing liquid carbon (careful for not burning the leaves). IME, BBA can be very persistent after installed so cutting off the infected leaves may also be an option. Allow 2-3 weeks for any effects to take place. After this time, assess what has improved and what can still be improved.
cheers,
GM