First grow, yellowing around buds.

It looks like iron is locked out and/or pH is too high.

coreywebster said:

I always thought with N been the most mobile stole from the low classes to give to the upper classes, sry, leaves, like a reverse robin hood.

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Right...as I noted
"With the yellowing moving down its not classic N deficiency. "

Cool, thanks churchhaze.

Is it best to drop the bloom booster for all plants in general or just our type of plants?
My pH is kept around 5-6 after I add the nutrients to the water and before replacing the water in the reservoir. So it looks to be iron lockout.

Thank you for commenting.

EDIT: These people claim that it could be that the water is too cold. Which is a real possibility this time of year in South Africa.

churchhaze said:

Aren't you supposed to use equal parts of A and B? Too much calcium nitrate will lock out magnesium and iron.

Try using the A+B in a 1:1 ratio and stop using the bloom booster.

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Came in this one late but, Church got this with the nutrient "cock blocking"......Next page has the OP giving the pH at 5-6 and I would be pHing to 5.8 and letting it rise to about 6.1 - 6.2 before adjusting down again. So maybe a tick low - BUT not the pictured problem!

Mag and especially Ir block!