Hi bcreighton7.
You certainly got your money’s worth and are quite fortunate to have had 30 years of use from your waterbed with only having to replace the top layer every few years, I agree that waterbeds have are quite a few drawbacks to “put up with” but for those who love the waterbed feel, the trade can be worthwhile. I am very glad to hear that the new latex layer feels comfortable and that it mitigated the pain resulting from your coccyx injury. I hope you’ll to get a few more good years out of it. 
Note: I removed the link you placed in this your post as this appeared in several other posts and it is against the rules of the forum here as borderline promotional content. I also removed the duplicate content from the TMASC expert area in Post # 3 here and kept your helpful suggestion to Phillip66. Thanks!
Phoenix