with salt inside, u will get reading from tds meter. it's normal....juz test it from the crystal pro will do. after mix salt no need to test liao.
as for the sg part, if i m not wrong, it's not stating that at 25 degree, the sg is 1.025. it state that at 25degree, sg at 1.025, the perimeters r as follow.....dKH 9+ ca 400+ mg 1300+ something like dat.....