I sometimes have damaged sacks that I cannot and will not sell, especially if there are holes and the lovely natural epsom salt are leaking out. But, I also cannot waste 25kg. So, what do I do with it? Well, one of the things I do is get my kids to dump all 25kg into my spa. I've had my spa for 3.5 years and have never had a problem running it with a sack of epsom salts. However, disclaimer here we come.... I am not recommending you necessarily follow my lead. Please check in with your spa supplier whether it is a good idea for your particular spa.
What do I notice? Well, there is a cloud of magnesium sulphate that bubbles out and it can be a bit strong on day 1. What I also notice is the way my muscles respond, melting and relaxing into the warm water. I sleep pretty well afterwards too. I figure if float tanks can use 1/2 a tonne of epsom salt, I can use 25 (and sometimes 50kg).
I'd love to hear if you do something similar. Email me on firstname.lastname@example.org with your experiences if you'd like to share.
* I have been advised not to post a photo of me in my spa! Ha! Consider yourself spared! *