1. Locate the electricity panel and shut the electricity off.
2. Use a hose to drain the spa. Open the hose and pump compartment of the spa and find the drain. Connect the garden hose to the drain and, after the hose is securely attached, open the valve to the drain. The water will begin to flow out.
3. Allow the spa to dry overnight.
Repair the Crack
1. Carefully remove the blister with a utility knife. Carefully remove the blister with a utility knife. Remove the blister with a knife. Be careful not to puncture the fiberglass layer, which is directly underneath the acrylic layer you are working on.
2. Mix together a two-component epoxy as directed by the manufacturer. This is a resin and a hardener that will develop after the proper dosage is combined and mixed.
3. Scoop some of the hardened mixture onto a plastic putty knife. Fill the crack and let dry.
4. Use sandpaper to smooth out the applied mixture. Use sandpaper to smooth out the applied mixture. Sand the area manually to make it smooth. Apply moderate pressure to the paper and sand up and down until the crack is completely filled.
5. Use steel wool to buff the crack. Use steel wool to buff the crack. Use a steel wool pad to make the acrylic shiny again. Gently rub in a circular motion over the crack. The area will be noticeable, but the crack will be gone.
6. Let water run before refilling the spa. Let water run before refilling the spa. Fill the spa with water again. Run the hose first for a few minutes to flush out stagnant water.
Notes:
You can ask someone who has experience in fixing pool liners as well. Never use a pool heater for heating your spa. The constant change in temperature causes the acrylic to expand and contract. It will result in more cracks.