I do it because the rep told me it was a good idea after I asked about it. Jacks is meant for tap water, which has some trace elements and minerals already. If you get the MOST with sulfur you can boost sulfur levels as well.
Hey Cap- good to see you around! So I have a couple questions for you, if you have a minute?
You've seen what I'm using above- do you have any glaring concerns about the mix I've described? One of the reasons I went with 4g/gal of Jacks in the bud stage is in fact to nudge the micros up a bit.
If one uses a bloom booster instead of the extra bit of Jacks, I can see why a little supplementation might be helpful. On the other hand, exactly which micronutrients are you trying to increase when you add some MOST? I add a bit of Epsom salts, again in the low concentration listed above, so I'm not sure what else the girls might need?
A little full disclosure here; it's recently come to my attention that I've been running my concentrations too low, leading to all sorts of deficiency issues. The way I did this was to use the ratios listed above to fill the RDWC partway full, then just add water until I got the EC I was looking for. On the bright side, the plants seemed to be somewhat deficient of everything, not just one or two nutes... I'll be upping my nutrient concentrations in RDWC to around 2.0 EC, having not gotten anywhere near that high in the past- and suffered for it.
The tap water here is very, very low in dissolved solids of any kind, so I'm not getting much nutrient 'help' from it. I'd rather add a known quantity of nutes to clean water than deal with the unknowns in hard water, so I'm not complaining!