I have added Premier’s “Arena Aid” and it does help with “bounce” but it needs a specific sand to work well. I also added “Foam footing” which was recommended here. It is like Reiten Right but judging on advertisements seems to be cheaper. I only added two inches ( per their instructions and my square footage) because I was on a budget and I already had Arena Aid. I wish I had added 4 inches. It does add more bounce but 4 inches would have been better. If I win the lottery I will add more…
The Arena Aid has helped with too much water/ not enough water. My arena has not had heavy use but I never had to water last summer during our drought. If you live in a more arid area this may not be true for you. Reiten Right and Foam Footing are chopped up yoga/ camping mats.