Mild Bathroom Cleaners
Mild bathroom cleaners may be used to clean the acrylic shell of the hot tub after the water has been removed. Spray the shell with the cleaner and use a soft sponge or cloth to wipe clean. The mild bathroom cleaner will both clean off any residue from the chemicals in the water, as well as disinfect the shell from any pathogens that may have been in the water.
White Vinegar and Water
Using a mixture of one part white vinegar and one part water will help clean your hot tub and work away at the calcium buildup and residue. The cleaning solution will also work to clean any fixtures on your hot tub. The tub should be rinsed completely of any remaining vinegar before being refilled.
A paste mixture of baking soda and water cleans off any calcium buildup and dirt that forms on the surface of the hot tub shell. The mixture should be scrubbed in using a circular motion. Rinse thoroughly before refilling the hot tub.
When cleaning your hot tub, never use any harsh or abrasive cleaners or anything that contains bleach, as these substances will harm the acrylic coating of the shell. These types of cleaners can also scratch or otherwise damage the shell. Only use soft cloths or sponges to clean the hot tub, because anything else could scratch the surface.