I'm new to this BBB method.

I have heard our pool-builder-supplier say that store-bought chlorine bleach is not good for the pool. Is there any substance to this? or is this just b/c they want me to buy their product?

We have a 2 year old 30k gallon in-ground pool. It's the regular cheap-o vinyl liner.

Welcome to TFP!

It depends on the type of bleach you get. You should not get scented bleach nor splash-less bleach nor specialized outdoor (furniture cleaning) bleach. These all have additives you do not want. The best is 6% Clorox Regular, though off-brand Ultra bleaches are also good -- again, all unscented. Clorox Regular bleach actually has "5.7% Available Chlorine" printed on the bottle because it is specifically registered for use in pools.

The proper bleach is identical to chlorinating liquid except it is at lower strength. The Clorox Regular has the least amount of "excess lye", even less than chlorinating liquid, so results in the smallest amount of net pH rise from the product itself.

Richard

Many people in the pool industry say bad things about bleach because they what you to purchase from them and they don't sell bleach. If you buy plain ordinary bleach, as chem geek just described, it is completely fine for pool use.

Do they sell liquid pool chlorine? If no then they are against bleach because they don't sell it . If yes then they are selling bleach (but they want you to buy THEIR bleach).
It's as simple as that. (Where I work we sell bleach).
Often liquid pool chlorine is a better buy than bleach.

Do I remember correctly, that with a vinyl liner you want to be a bit cautious about adding bleach as it could bleach out the liner itself?
--paulr

Bleach is chlorine. Chlorine is bleach. So if you use a different form of chlorine, like tablets or granules, anything used improperly and you can experience "liner fade".

When you have to be careful is allowing granular chlorine that has not dissolved settle on the liner, it will "bleach out". Same for letting a puck settle on the floor. Also be sure there is circulation when adding liquid chlorine, like bleach, because it can "puddle" and lighten in one area.

I have noticed no fading of my liner from using bleach. My pool has never looked better.

You have to be careful about any form of chlorine to keep from bleaching the liner, doesn't matter if it's 'bleach', pool chlorine liquid, cal hypo, lithium hypo, a floater with triclor pucks, or dichlor. Any of them can bleach a liner if the chlorine level goes too high for too long or if concentrated chlorine source falls directly on the liner (usually when shocking with a solid form of chlorine.)

Here is a history lesson as far as bleach goes, before liquid bleach was common we had 'bleaching powder' that was dissolved in water. Guess what it was--cal hypo! Back then that was what we called bleach! Bottom line is that chlorine is chlorine.

Check, chlorine is chlorine. Although my grandma used bluing, not bleaching powder! (In the laundry, not the pool....)
--paulr

She might have also used Javelle water, which is sodium hypochlorite, if she lived long enough ago!