Tearing usually will not have much of an effect on the water colour. In most cases when you tear there is not much bleeding. However if when you tear you damage a vein or an artery then there can be quite a bit of blood. How murky the water gets depends upon a few things including if you pee or poo, if your newborn poos, if your waters break when in the pool, how much bleeding you have after your baby is born. I usually carry a small scoop so that if mum does poo I can quickly scoop it up and dispose of it without too much trouble, and hopefully without mum seeing it. (saves embarrassment)