brown spots

Hey, first attempt at all this, I have a 1.2x1.2x2.0 tent, running a 400w hps with 119 intake, 150 extract and a 6 inch circulation fan. in my third week of growth and one plant in particular has developed light brown spotting all over the leaves, general plant health seems okay bar these spots. I'm using canna professional mix and was using canna start but stopped after these spots started developing.

look like a Ca (Calcium) Deficiency

View attachment 2821312View attachment 2821313


what kind of soil do you use and more important what kind of water do you use ?
RO ? if so you might need some extra Ca

(also if your tap/well water is low on calcium you need it, high Ca in your tap water = white spots on your bath room floor Etc )

thanks so much, I use normal tap water, might try and purchase some deionized water for next grow but in meantime ill go purchase some hydrated lime. thanks again

yea if your Tap water is low on Ca/Lime you can add some yourself, there is also a bottle with liquid Ca/Mg+ that will do the job and also add Magnesium

them two secondary nutrients is the two most important once beside your normal N-P-K that Mj need to thrive (just don't over do it, but thats go for everything when growing)

micros like Iron, Bor, copper and Zinc Etc is not that highly needed in the same amounts and if you use a good soil and Tap water it rarely become a problem, but the Ca and Mg is something the MJ plant need in bigger amounts in order to uptake the water/nutrients and for its cell structure aso.

yea it seems most my nutes are lacking calcium but have everything else covered ill water with some lime and adjust the ph and will update with an outcome, thanks for the help