And my interest in this thread is due to my camco 5500 straight element rusting. From my experience, magnesium anodes prevent rusting when the kettle is full of water. What they don't protect is against rust when the kettle has just been drained. I ended up getting rust on my element threads due to the water drops that remained in contact with the base (the water was no longer electrically connecting the element base with the anode).
Also, during my leak tests with the anode installed I could see many small bubbles coming directly from the anode. Once I drained the kettle, I found a film/deposit on the kettle wall near the anode. What are the bubbles, what is the film? Throw in the fact that I still got rust on my element face the next day and you can see why I threw out the anode.
Once I took the anode out, I did another leak test (overnight) to find the element face had rusted further while submerged (this did not happen with the anode--the bubbles and resulting film are evidence that the anode was protecting the element when the kettle was full).
I could go the silicone route to try and prevent rusting, but I don't want that in my beer either!
Ultimately, I cleaned the rust off and will be brewing a batch tonight. I will not be leaving my kettle full of water anymore (only did it during the leak check) and I will dry the element threads when I'm done brewing. I've read that most people have issues with rusting in their hlt (I'm doing BIAB-ish setup) so hopefully I won't have the environment that leads to rusting.
I looked into bremations element but none of their products will work for me (I can't use a ripple element due to how I mount my element) so if I have any more rusting issues I will probably purchase this:
http://www.ebay.com/itm/Electrical-...678?pt=LH_DefaultDomain_0&hash=item2a30ecff66
I only wish it came in higher wattages but 4000w will be fine for even a 10gal batch. But why not have more power? It just makes the water heat up quicker hence why I went with my 5500 ULWD element even with the fact I will mostly be doing 5 gallon batches. Also the element linked above looks to have more length than the element acidrain purchased...not sure if it is a LWD but it might be close.