you are more than likely experiencing micronute issues due to your brita water filter.

Do not filter your water.

Here is an except from the FAQ on Brita's website

# Does the BRITA water filter cartridge remove all minerals from drinking water?

The BRITA water filter cartridge only partially removes the hardness from drinking water. This part is temporary hardness, which causes scale deposits during cooking. It does not remove all of the minerals from the water. It reduces the concentration of calcium and magnesium with cation ion exchange resins, but theses substances are not completely removed as in desalination systems or industrial plants that use reverse osmosis or distillation processes, for example.
# Does the removal of temporary hardness affect calcium levels?
Yes, but mostly in the form of temporary hardness or limescale which is not a good source of dietary calcium. This will not have a significant effect on the calcium intake of those on a normal diet.


If you're going to use a filter of any type then you will probably need to supplement with CalMag as a bare minimum to avoid problems.