Apart from reconnecting the connections and filling it, there is nothing complicated in preparing a spa for the new season. This practical advice will help you avoid certain problems.
Before filling it
Check wheter your spa is sitting solidly on its base, especially if your base is a concrete block. It could have moved during the winter.
If the interior of your spa jets were not removed (for those in which it is possible to remove them) when the spa was closed, it would be a good idea to remove and clean them. However, this can be done only with rotary jets.
Clean the acrylic surface of the spa with a special product designed for this operation. You can find it at your pool specialist's.
After filling it
Once the spa has been filled, take a water sample to your pool expert to have the dosage balanced. Nevertheless, the first product that should be used is a descaling agent. This will prevent the formation of calcium on the spa's heating element. If you find that your spa does not heat up as much as before, there is a good chance that your element has calcified.