Old thread, but perhaps a new idea to consider, most titanium alloys contain vanadium at some level, and as the titanium alloy breaks down in your tank (yes it does that slowly) it can liberate some of vanadium also contained in it. Many chillers and heaters use titanium, and stray voltage in your tank can cause the titanium to break down faster. just a thought, but might be worth considering Unless your critters seem distressed I don't think it is worth worrying. I would be surprised if it would accumulate to any harmful levels if you still occasionally are removing some of it through water changes.