Should I add aquarium salt for water changes?

I have a 50 gallon tank in operation for more than a year. Equipped with three 3 spot gourami and a small school of tiger barbs. I do a water change of 25% and vacuum twice a week. My phone is always very low (5.5ish) but I think my fish have adapted, but I have not had much luck with new additions, although acclimate then very slowly. Just wondering about salt in general, and related to pH.

Yes, you should use the aquarium salt every water change depending on the amount of water out Changde. In addition, to increase pH can try to use crushed coral in the filter. But do not mess too much with the pH as the fish do not like this. But definelty increase its pH very, very slowly gradually.

Aquarium Vacuum Demonstration