We will confirm that all lights have been turned on and attach a yellow tag indicating that they should not be left on if your pool is not empty.
Painted pools also tend to get dirty and don't bond with the plaster long-term. You can also do it yourself if the pool has already been painted. I would recommend that your pool be re-plastered by a professional rather than being painted. It won't make your pool look good long term if it is painted with plaster.
There are many options for pool heaters. You can choose from gas or propane models as well as heating pumps, electric resistance heaters and solar options. They all have different costs, but on average you will spend anywhere from $1,000 to $8.500 to add a heater for your pool, depending on how big and what type of heater.