Nothing destroys a cover faster than poor chemical maintenance of your spa, besides jumping on the cover. Chemical burns can show very quickly in a spa with poorly maintained water. Here is how to prevent chemical burns on your Hot Tub cover and why you should do it. Don't know if your cover is suffering yet? If your cover looks like this image, which we call the "hamburger effect", then it's been suffering.
The three hot tub chemical issues that damage hot tub covers
Here is a cover with a good poly wrap that is intact, and then a poly wrap that has eroded and was torn due to the erosion. You can tell because of the "blocky" look to the tear.
.1. Unbalanced ph is the most common culprit of hot tub failures. High ph won’t effect your cover, though it is still bad for it to persist in your spa, low ph is what damages your cover. Low ph is acid, and with an acidic environment the vapor from the acidic water will attack everything, including the bottom side of your cover. Test your water at least weekly and make sure your ph does not get away from you. Keep it in the "OK" bracket of your test strips.
2. High free chlorine levels (FCl) create a corrosive environment in hot tubs. This is one of the reasons we prefer to not use chlorine in hot tubs, but excessive bromine use can cause high free chlorine counts as well. Keep your Free Chlorine (FCl) count in the "OK" bracket of your test strips.
3. Shutting your cover after throwing in shock creates an similarly corrosive environment in the spa. Shock Oxidizer and Multi-Purpose Shock (MPS) oxidize chloramines, and with this oxidation process gassing the chloramines out of your water you want to make sure it can be released into the atmosphere. Otherwise, with no other place to go your cover will oxidize and erode the poly vapor wrap inside your cover. This is probably one of the biggest reasons people have to get new covers. Simple solution is leave your cover open for 15 minutes after you shock.
John & Matt
These are our top service technicians, from where we get all our good info! They have been working on spas for years, and we're grateful that they can share the things they have learned.