Well, to add to what Jason said, it isn't sustainable unless you plan on draining the pool at the end of swim season. Some with small above ground pools like yours do just that, so using tablets isn't the end of the world for them.
I will say that if you are maintaining the FC correctly, (yours is actually high) you do not need to do any additional treatments with any shock products. Save your money. The pool stores like to tell folks they need to shock weekly, bi-weekly, monthly, etc. It isn't true. When I switched to salt I had someone tell me that I would have to shock every month, that it is part of the maintenance. He said this came from Leslie's, so it had to be true. I have never shocked my pool since switching to salt.