You may have heard that you should always purchase your chlorine from a trusted pool store. Why is this you may ask? Well there are a few different reasons, and all of them lead to one conclusion. Expired chlorine can be harmful to your pool.
Liquid chlorine has a shelf life of 30 days, meaning it contains its full strength for this amount of time. After this, it can lose its full strength and drop to only 90%... 50%... 10% effective in your pool water. (Liquid chlorine can also lose its strength faster if left out in direct sunlight) At Angie’s, we rotate our chlorine daily. This means when you purchase chlorine from us, you can be confident that you have the newest chlorine available.
If you go to a big box store, oftentimes, they only get one shipment of pool chemicals per season. This means, there is a risk that you are purchasing chlorine that has been sitting there since the beginning of pool season. When the 4th of July rolls around, this chlorine could be around 3 months old, making it about 50% as effective as it was when it was first delivered.
If you add expired chlorine to your water, you are taking the risk of increasing your combined chlorine which could lead to a chlorine lock. Combined chlorine is essentially dead chlorine that is not properly sanitizing your water. If you ever find yourself with a chlorine lock, the ways to treat it are super shocking, adding non-chlorine shock, or draining and adding fresh water. All of these take time and money - and could be avoided if you would have used fresh chlorine.