Hi usmcwf84,
Post #89 here has a description of the various different types of mattress protectors and the tradeoffs that are involved with each. For a memory foam mattress one of the thinner membrane type may be your best choice and would be the most common choice because it will have little effect on the feel and performance of the mattress and is waterproof as well although it may increase the warmth a little because it isn’t as breathable as the other two types that are mentioned.
Phoenix