I’ve noticed a white hard deposit along the water line on the tiles. Our guess is that it may be calcium deposits. If that’s the case, what would be an appropriate way to get rid of the deposits and to prevent it from happening again? In one of your answers we read your suggestion about using Mineral Treatment and lowering the overall pH (to 7.2 or so). Would this be advisable to do in our case as well? Are there any specific recommended brands for the Mineral Treatment and how do you use it? Thanks!

Most likely the deposits are calcium scale. This pool problem is most likely due to the water reaching the saturation point, so far as calcium hardness is concerned. These deposits can removed using a strong muriatic acid solution. Apply with a sponge and make sure to wear rubber gloves and eye protection. First, test in a small area to see how it will affect the deposits and the tile. If your calcium hardness level is above 400 PPM, you will have to add a quality, phosphate-free mineral treatment, such as Liquid MetalTrap – possibly several times the suggested dose – in order to try and avoid a recurrence. Your local pool professional should be able to suggest a product. Keeping the pH closer to 7.2 and the total alkalinity closer will, also, help reducing the scaling tendencies of the pool water. For more information on the topic, refer to the “Langelier Index” page. The addition of a Magnetic Water Conditioner might be able to help resolve some of the scaling issues.  I hope that this recommendation works out for you.