That's what I was thinking, noted for future reference, I'll use this to finish these off and buy seperate elements! cheers guys!
yup, Ca defc.! What are you growing in? Ca can get less available under 6.0, so maybe get the pH in low 6's-- pending your medium!... and as mentioned, demand is high at this stage,.. some plant also just seem to need more,...
... molecular size has nothing to do with it mate, and it just the atomic cation Ca++ that's getting absorbed.. in solution CaCO3 dissociates into Ca++ and bicarbonate/carbonate, which the plant does nothing with (it's involved with pH buffering though)... and epsoms are only MgSO4, no Ca in there,...