Excessive efflorescence is considered a symptom of an excessive moisture problem.
Shower floor grout turning white.
What i do have though is darkened grout near the middle of the shower size of a dinner plate.
The minerals in the water crystalise which results in white residue appearing on the surface of tiles.
Known as efflorescence white stains appearing on the surface of tiles is caused by water penetration underneath stone or tiles.
But on grout and shower curtains pink mold is really just a cosmetic issue.
Topical sealers acrylic sealers which coat the grout joint and are not vapor permeable may turn white from reactions between the acrylic and moisture.
The most common reason is moisture from the ground below the slab but grout may also turn white from the rain in outdoor installations or in rare cases from water used to clean the floor.
So no you do not have to remove the grout.
Grout turning white can be caused by efflorescence which is the calcium from the water and the underlying concrete or mortar migrating up through the porous cementitious grout.
My shower floor is the same type as this person s i don t have that odd white discoloration though and no cracked grout along edges.
The bacteria grow on surfaces that stay damp for long periods especially where there is also soap scum.
This is not efflorescence.
Another possibility is that grout containing polymer was used and exposed to too much water before the polymers had a chance to combine.
A week later the line turned white.
The problem you have is called efflorescence which occurs when any concrete product is over washed before it is cured.
When they dry out on the surface the remaining salts appear white and powdery.
They have an efflorescence remover on the market but they only work so well with grout.
Make sure that you get a good sealer onto that grout before you get after it again with water.
Under certain circumstances a white powder can form on grout especially on floor tiles.
I am assuming that the white jagged line represents a crack in the grout and the white is efflorescence.
It is due to soluble salts rising to the surface of a cement based product.
Rather this is similar to the whitish haze seen with floor wax when it is applied to a damp surface.
Some caution must be observed in selecting the sealer.