Calcium leaching from grout.

[PoolDoc]

Hi All

Good catch, Duraleigh, on the bogus numbers. More and more pH meters are being sold without buffered calibration solutions OR any explanation of why calibration is essential. We can expect to see more and more off-the-wall pH results, as people use pH meters. The meters will usually (if they aren't made by Hanna) be accurate out of the box, but will drift over time.

However, given the "78" for CYA, I'm suspicious of just where those numbers came from. Denny indicated he tested the pool himself, but unless he's got a photometer (Palintest is selling one) it's unlikely he generated that number himself.

So, like you, I'm left wondering where they came from.

Waterbear . . . acid doesn't dissolve salt. The water in it might . . . but if that were the case, so would the pool water. One general rule: if acid makes it fizz, then it's calcium carbonate deposits. In some parts of the country (eg. AZ), pool owners will have problems with calcium or magnesium sulfate deposits, but it's generally pretty rare. Also, it is common for calcium carbonate laden water to migrate through grout and/or concrete, and deposit stalagtite-like drips and runs. The acid-fizz test will ID those. Also, I have heard of silica deposits being an issue, but I've never confirmed that, or gotten more info on it.

Also, while I'm pretty confident that spectrophotometers from Hach, et. al. are accurate and reliable, I have no such confidence in the low end equipment used in pool stores. My own experience with some of those units has not been positive. Many of these are sold without any calibration process, and even where there is a process, there's no guarantee that it's been followed. It's important to remember that bad testing actually improves pool store profits, so from their point of view, there's no benefit to accuracy.

Ben
PoolDoc