A pH of 7.4 is very low. It only occurs in a very few areas in the world naturally, typically west coast equatorial zones where deep water upswelling occurs. Even then it is quickly diluted to a higher level. First I would suspect your test kit, either it has expired or there is some other problem. I would go to another place and have the water tested, most LFS will do that for free (a happy customer spends money).
I wouldn't say low pH won't cause cloudy water, but if there is a chemical imbalance, it could cause issues. But adding baking soda to a tank may cause cloudiness for a few days as well. The other possible (probable) cause can be a bacterial bloom that can occur in new tanks. Of course new tanks and new sand, especially fine sand, can have coudiness issues at start-up. Strong mechanical filtration will help clarify that, and there is an additive that helps bind the small particles and helps clarify the water. Not sure the name, but it was mentioned in another "getting started" thread.