You may still experience corrosion on new ladder anchors, especially in a salt water pool environment. The question is, when they redid the patio, did they redo the anchors with the correct bonding/grounding – and did the bonding wire touch the pool/equipment and ladder anchors properly? If this line is cut or modified in any way the ladder will not be protected.

To eliminate this issue, plastic anchors can be used, as they will not need to be connected to the bonding in the same way that stainless would need to be. There are also plastic ladders available, which are great in salt water environments.

If it is possible to connect to the bonding wire, stainless ladder cups can be used again, and it appears you can purchase the ladder cups on amazon.