tap is fine and even preferred in many cases. it provides fe, ca, even cl is useful to a plant in lower amounts... just like it is an important ion in our body chemistry. your propogation of a signal along your neurons depend on it and others.
Find your local water report... if under 300ppm, it's probably fine to use. I have pretty hard water at about 250ppm, for example and have no issues. For last 6 months i stopped leaving it out for 24 hours to "evaporate the chlorine"... which nowadays is possible chloromide(may be spacing ) and that one isn't going to evaporate whatsoever in 24 hours of any note.. lol..
Cl will go the way of the dodo with just a little sun applied, but again, not worth the effort. the plant needs it anyway.
Soft water obvviously is a no-no.
if that soil is "hot" AND you've been feeding consistently the whole time, it's likely a toxicity.
Some deficiencies look like that, so you'll need to ponder recent behaviour and make a better judgement wiht that information as to which it is more likeyl...
always safer to ease off than try to undo adding something that doesn't help. Always be certain before you add anything beyond a well-rounded feed at proper concentration.