What is the issue with the filter in a VX tank? Can it not be removed before the coating process?
I have a VX with a leaking tank; I was considering the DIY approach, but have found a firm - Hartlepool Radiator Company - who clean and coat both inside and outside of the tank. Not cheap, I think it was over £200 when I inquired.
If it is something you need to be aware of before a DIY job, then surely the pro's can do the same, if they are aware of the problem?
I've not done it yet, but hope to be in a position to get it sorted soon.