Is it necessary to shock a pool?

[PoolDoc]

"Shocking" is a pool trade term with many conflicting definitions, but the common thread in most of them is that "shocking" involves quickly raising the free chlorine to a level 2x - 3x normal.

For most people, it's necessary because they are erratic in their pool treatment, and "shocking" can penetrate emerging algal biofilms before they become a serious problem.

One common misconception, which is artfully promoted by some pool chemical companies, is that "shocking" involves different chemicals than regularly treating with chlorine. It's true that trichlor is not a very practical 'shock', but all other forms of chlorine -- cal hypo, bleach, or dichlor -- are.

[Thatcher]

Thanks for the quick response.

One other question-
Are you aware of anyone making some form of chlorine tab that could be used in a chem feeder and does not contain stabilizer- or at least lower levels of it? Trichlor is ideal because of the convenience, but I'm sure I will eventually reach a point where I am forced to switch to bleach to avoid high cya levels. Seems like that would be a good opportunity for some chemical company to sell more pool products.

[Watermom]

Unfortunately, no. If there were, there would be a lot of people interested in using them, though.

[CarlD]

HtH and its sister company (PoolLife? or something) made a cal-hypo tab, first one in a plastic tubethat dissolved, then one without the tube.
The tubeless ones were pure garbage, becoming a pile of mush in less than a day. Never got hold of the tube ones but they were reputed to work much better.

But there are two caveats:
1) Cal-Hypo raises the calcium level in your pool so you have to stop using it at some point, plus it can be a bit alkaline, raising your pH
2) Never, ever put the tabs in a chlorinator or floater that had tri-chlor or di-chlor in it, and never let bleach touch cal-hypo! Very Dangerous!