https://www.amazon.com/Fhiny-Platform-Tortoise-Terrarium-Accessories/dp/B09K45K282/ref=mp_s_a_1_8?crid=3N8BMVCUWJFFJ&keywords=basking+platform+for+aquatic+turtles&qid=1646874219&sprefix=basking+%2Caps%2C1192&sr=8-8

Here's a backing platform similar to mine. Don't go by the feedback it's good enough for a pool.