The likely problem, especially with Cl, is the build up, whereas the same effect is not present in the SO4 build up, plants will consume/assimilate both anions in tissue, but seem to be less sensitive to high SO4 vs Cl.

Note, this is mainly speculation, no one has shown this. Still, thr evil I do know and use is the GH booster or Seachem's Eq.

Both of which use all SO4's for the anions in CaSO4, MgSO4, K2SO4, FeSO4 and MnSO4. But a little Cl is not bad and helps, same with a little sodium, but it should be fairly low. So adding some KCl, or CaCl2 every so often will not hurt too much.

Adding the GH booster works very well. I really have not done enough with Cl isolated to say much with many species.
Same with Zn, MN, Na, SO4, etc.


Regards,
Tom Barr