what could be causing burning tips

[asylumdown]

Also I'm losing faith in my Hannah checker for alk. It keeps telling me I'm over 8, but if you guys think this is low alk, then do I have a testing problem, or are those GFO related issues super temporary? I've never tested it immediately after changing GFO, I always test before I drain for a water change (and thus before I change GFO) so I can get a sense of where my tank is at after 7-10 days of no human intervention.