If you're growing in soil (or coco), then get a ph pen. Also get some 'Bloom-CalMag' and some 'BioBizz AlgAmic'. Add those to your water and then adjust your water ph to 6.5. Using this each watering will eventually sort out the issues. You can also flush the plant before starting to use the correctly ph'd feed - flush with at least 3 times the capacity of the container using ph 7 water. Collect a little of the run off, both at the start of flushing, and the end - measure the ph of these. Doing this will probably highlight something of the problem. But yeah, the cal/mag and the micro nutrients, combined with correct ph will sort it all out. Might not be the greatest grow this time, but learn and they will get better and better.
There are other cal/mag and algae/seaweed micro nutrients, which would be good too. I recommended the ones I did because I use them myself, so can vouch for them (see the grow in my sig, and my 'Sugar Punch Grow'). When I started growing I experienced things like you are, and kept addressing the symptoms and therefore kept suffering the same problems (which I needed to solve). By doing what I advise here I have cut out 95% of problems - with the 5% being easily dealt with by small adjustments.