I will try as much as possible. I am all for more frequent dialysis especially in situations such as calciphylaxis. The most important issue would be to lower serum phosphorus as much as possible to as low as 3.0 if achievable. Daily dialysis would go a long way in accomplishing that goal. In practi...

I typically don’t, although that’s an option. The majority of these cases are related to non-compliance, so adding an extra HD session is not to go well with them. If they are agreeable then I would go for it. 

Optimally I would: Stop or change warfarin Stop any Vit D or analogs Dialyze on lower Ca Bath (dialysate)  Stop CA-based PO4 binders Give Vit K Increase the frequency of HD Give sodium thiosulfate as tolerated by patient's [HCO3] but I would prefer to increase HD than cut the dose