First on the cloudiness...this can be due to stirring up the substrate (moving plants you mention), in which cdase the particulate matter will settle out. It can be a bacterial bloom (if whitish) due to the high organics in the tap water added (or stirred up from the substrate and/or filter) and the bacteria that consume organics (different from the nitrifying bacteria species) multiplying rapidly (roughly every 20 minutes). If it is green (photo does not suggest this to me) it is an algae bloom caused by the rapid reproduction of unicellular algae. Any of these should clear on their own, though that can take anywhere from a few hours to a few days.
On the pH...do not use pH Up or any other chemical to adjust pH. These usually are not effective (the pH is closely connected to the GH and KH, and other factors) and fluctuating pH is worse for fish than leaving it alone. However, you do have an issue here as Colin noted. The platies are livebearers and these need moderately hard water, a GH of 10 dH minimum, in which case the pH will naturally be above 7. However, the other fish mentioned are all soft water species and they are fine with a low GH and acidic pH. Natural methods of raising GH and pH are safest, but this is not as easy as it sounds.
Before going down that road, what is the GH (general hardness) of your tap water? This will tell us how to proceed. The GH is of more importance to these fish than pH, so if there is to be any adjusting of water parameters it should be the GH that is targeted; the pH will follow suit.