Adding sodium bicarbonate would have a quicker response to bring ph up, be careful to let the ph rise slowly. coral chip added to the filter would raise ph and maintain it at a level. Some even use oyster shells to achieve the same effect.
BTW, what kind of fishes are you keeping?
I have found that African cichlids require hard and alkaline waters, and a salt mix is the best way to keep the ph and gh high.
Whereas Central American cichlids do well in medium hard waters, with a ph of about 7. South American cichlids thrive in a lower ph environment with softer water. Tank bred fishes are not as sensitive as wild caught ones, but I've often seen colleagues keep SA cichlids in CA water with the result that the fishes get stressed and combined with poor water management end up with lateral line erosion or "hole in the head".
My Asian arowanas are all kept in ph neutral waters (ph of 7) but I don't use any coral chip because I don't want the hard water it creates because the additional calcium carbonate (we believe) damages the beautiful scales.