Store-bought bleach should not be used to chlorinate hot tubs or pools unless it is regular bleach. Splash-less bleach, or bleach with a scent additive may cause water care issues and/or foaming.

While store-bought bleach is typically not recommended for use as a source of chlorine, you will find that it is indeed the exact same chemical as the liquid chlorine used in pools; sodium hypochlorite. It is typically around 6% strength, whereas pool chlorine can be at 10% strength or higher.

That being said, you certainly can use bleach, but you should be very careful to ensure that you are using it safely; ensure you have a working hose nearby to thoroughly rinse any spills, and if you happen to get some on your hands, you must wash your hands continuously until you no longer feel an unusually slippery feeling on the affected skin.

3 fluid ounces or 6 tablespoons of 6% bleach in a 300 gallon tub should yield an increase of roughly 5ppm of free chlorine.

First, fill your tub up to a reference point. (The bottom of a headrest works well, though you can also place a piece of tape just above the waterline)

If over the course of 7 days, your water line goes down by an inch or more, you are likely contending with a leak.

You should always check your drain lines first to potentially save you a service call. A loose drain cap, or a cap lacking a rubber gasket on the inside will allow water to escape slowly. (It should have a gasket like the female end of a garden hose)

Hot tub supplies can last a very long time if stored properly. All dry chemicals are very stable if kept out of the rain and the sun. If a dry chemical becomes compacted and hard, it is better to replace it than risk getting it in your eyes trying to break it apart.

For test strips, moisture from your fingers is the main concern; if the colors of the pads don't look as they did when new, or you get wild pH readings, you will want to replace them.

Liquid chlorine degrades based on temperature and initial strength; a 6% strength liquid chlorine can keep most of its strength up to 1 year if kept at temperatures lower than 75 degrees Fahrenheit, and even longer if refrigerated, but that period gets cut in half at temperatures approaching 85 degrees, or at higher concentrations.