I recently replaced my water softener w/ a GE model number GXSF40H and I have extremely low hot water pressure on some faucets. I also noticed that there is white debris at the spigot. I also have a tankless water heater. How do I solve this issue?

Did you use white teflon tape when you installed the softner? Could it be tape, bits of salt or a build up of calcium that has broken loose. Tell us about the texture and feel of the debris between you finger, roll it around. Once we fifure out what the debris is then we cure that issue and remove all cartrdiges and aerators to clean them all out.

It seems as if it is calcium buildup...