Should be no problems.River sand will usually be a little coarser. Personally I prefer finer sand as all debris will definitely stay on top. Even though it is meant to be pre-washed I would still rinse it more before adding it to the tank. I usually fill a 20L bucket with half sand, then fill it with water and stir it all up, let the sand settle and tip the excess water out.I repeat this until the water is clear. If it clouds your tank water, you haven't rinse it enough.
