Was it after the play sand that the tank got cloudy? From what I've read play sand can be very fine and can be very inconsistent. It is fine for what it is meant for but can be a problem in tanks and can cause particulate to hang in the water.
Here are some of other people's comments;
I've used it. It doesn't change the water chemistry at all. But if you like vacuuming your substrate, even hovering above it with the gravel vacuum, forget about it. Play sand is very fine, finer than almost any other substrate, so the smallest of disturbances sends sand particles flying.
Play sand does not have to meet any particular specification, as far as I know. It would have to be relatively clean and free of broken glass, or other unacceptable debris. But, it could be limestone and would be perfectly acceptable for its intended use, but not for a planted tank. Even pool filter sand varies widely in appearance because appearance is of no concern for that job. But, I don't believe a sand that changes the hardness of the pool water would be acceptable as a filter media, so at least you don't have that to be concerned about with filter sand. In fact any time you use something not specifically sold for planted tank substrates there is a chance it will affect the water - even SMS did that for some people. But, that is still the way to go for really cheap substrate.
I have spoken to some locals who have used both pool filter sand and play sand, one local in particular who used both told me that he went through 4 filter impellers within a one year period when he used play sand, largely owing it to it being lighter than pool filter sand and being easily stirred up sending fine sand grains through the impeller. He stated that he had no such issues when he switched to pool filter sand. I think you are at greater risk of impeller damage using play sand vs pool filter sand, especially if you have bottom dwellers that continuously stir up the substrate.
After setting up some breeders over the weekend with both play sand & pool sand I would recommend getting the pool filter sand. Its much easier to plant, clean and setup. The play sand was a mess and took a lot longer to settle than the pool sand. Play sand also had a tendency to snap stems when I was trying to plant them, where as the stems planted almost effortlessly in the pool sand. Also be careful when buying pool sand, try and check the grade if you can. I got three identical bags; two bags that were perfect and one bag that was fine almost like the play sand but not quite as bad, so even with the pool sand there is some variance.
On the other hand;
I used playsand for years.. providing you rinse it you shouldn't get any dust or fines.. it's the easiest substrate to hoover I've ever tried (after rinsing out the fines.. mulm just sits on the surface of the sand)).. Crypyts and Vallis both love it - as do Corydoras, banjo cats and other substrate sifters/burrowers. It's surprisingly dense once settled and roots really run through it.
So you'll have to decide yourself if that is the problem or not. Maybe you can experiment a bit to see.