Ortega Check valveReturn Line 1.5 inch White 010646, V20-339

Will they freeze and crack

Are these adjustable to make less of a waterfall?

The description says it is 1.5". is this the outside diameter (including the threads)? i need 1.75" od (1-7/8" including threads).

My spa drains down half way after the pump stops bc the spa is above the pool. A pool guy came out and said this pt would correct the issue. Will it?