You can use the clarifier with reasonable safety (that is, little risk that it will make things worse) so long as you do NOT exceed the label doses. It may, or may not, help. But if you don't overdose, it probably won't hurt. If you DO overdose, it can make things MUCH worse!

However, polyquat is itself a very effective clarifier. You may want to give it a day.

Do raise the pH, but only enough to be just barely above the lowest level on your kit. And, yes, you can use soda ash. However, if you do, add it in small doses to the skimmer.