My floating iPhone holder

[Kryos]

Wouldn't Acrylic be better? It's lighter and clearer then regular glass. It's like the viewing boxes at the LFSs. I made one out of acrylic for myself in fact, but I don't use my phone with it. I can float my box in my tank without any foam, not sure if the weight of a phone will make a difference, but you can just increase the height and surface area of the box to increase Buoyancy.