There may be outside influences, beyond water chemistry, that may impact the cleanliness of your pool. One example is the use of mortar during installation of concrete and tiles on your pool. Water could splash into the mortar causing the concrete to “cry.” The “tears” that occur will be of calcium sliding down the sides of your pool walls. The photos below shows the build-up after only one week. To prevent this from becoming a major issue, it should be cleaned weekly.  If left unattended, it could cause an accumulation that will eventually result in the pool needing to be sanded and refurbished – which is a major repair charge.