Well I guess I might have stirred this discussion, which I think is a good thing as it looks like it may have been under the radar as ken said.
This is my experience with HITH. When It started to show up on my mono @ 16" and my hybrid @ 17-18" I was very frustrated and felt like a failure to my bass. I then immediately started reading everything I could, and decided on the following plan. I increased my water changes drastically and then later installed a drip, I also started adding vita-chem to the Tilapia and prawns I was feeding and also started feeding them Massivore again as I had stopped as they got big because it was expensive. After doing all this the HITH had stopped and disappeared in about 3-6 months.
Still not sure to the route cause, maybe my nitrates as they went from 30ppm ish to 10-5ppm. I don't know if Thiaminase causing Thiamine deficiency causes it, conditions to the water, or the lack of Thiamine in the aquaria, I just tried to fix as much as I could. Ken and Hu have some of the most insane filtration, so I would think maybe the water has less to do with it than I thought, but maybe it truly is several things that could cause it. I would like to know more of what you guys are feeding including supplements and what percentage of water is changed weekly with your back-flushes?
I'm very happy that Hu called the problem out in this thread as I think it will help the cause. I was a little ignorant to how it was effecting more than I thought with some serous devoted keepers doing all they can to provide the best care to their cichla being effected.
http://www.monsterfishkeepers.com/f...-IN-THE-HEAD-THIAMINASE-What-you-need-to-know!!!!!!