Would this be strong enough to use as a hot tub base?

The QUIKRETE® Walk Maker® Forms are typically used for creating walks, paths, patios, courtyards, etc. All of these are applications are typically only subjected to pedestrian traffic. The individual concrete paver pieces made with the QUIKRETE® Walk Maker® Forms will not provide a completely solid base for the hot tub and will potentially shift and move depending on the base underneath. You may consider using Pro Finish by QUIKRETE® Crack Resistant Concrete Mix (No. 1006-68) or Pro Finish by QUIKRETE® 5000 Concrete Mix (No. 1007-85) to pour a solid concrete pad for a hot tub. You may call us at the QUIKRETE® Technical Center at 1-800-282-5828 if you have any further questions.