What to use to weigh down chairs on tanning ledge?

[Esloser]

What would you use to weigh down plastic chaise lounges on a tanning ledge. I found two plastic chaise lounges for our tanning ledge. They are the perfect height - keep about an inch or two of the lower body in the water while relaxing. However, if you get up they start to float away.

Was wondering if anyone had a unique solution? I didn't want to add metal weights for obvious reasons. Was thinking sandbags, but that could turn into a huge mess.

 

[atttech-2]

Bricks that have mortar holes all the way through them work well you can use nylon string or zip ties to attach them, ideally so they don't even touch the surface of the pool just hang under the chair. They dry quickly and unlike sand will not spill or harbor nasties over time.