Product review (4 stars): Water treatment tablets help keep humidifier clean
I find these water treatment tablets very useful keeping the heating element and inside of my room humidifier clean.  They do help.
However, I don't rate this product a full Five stars because of two reasons:
1 - they're hard to find these days.
2 - they are labeled as three (3) months supply, which I find hard to believe.  I use one tablet in the tank each time I refill the tank, which is every day, if I use the humidifier on high, or every other day if I use the humidifier on low/medium.  Now, for the very cold months, when our house is very dry, these tablets will last me between 12 to 24 days; much less time than the THREE MONTHS SUPPLY as claimed on the package.
However, as I don't use them year round, they will last a while.

Now, these tablets are out of stock, but when I need more of them, I hope I can find them.