Over time the surface may become less slick. There is one surefire way to make the pool slide slicker again, but it will cost you a bit of money. You can buy a kit to refinish the slide or hire a professional to come in and do it for you. The chances are that you are not going to want to do that, and, yes, there are cheaper options. Here are some things which you can try to revitalize your pool slide.
The first thing to do is to make sure that you are taking care of it. By regularly cleaning your pool slide, you will keep the material in good shape and stop it from wearing as quickly, which will keep it slicker.
Use a cleaner that will not damage your slide and a cleaning sponge which is not abrasive. Use a mixture of soap and water to clean down the slide and remove any grime. Make sure to wipe off the soap when you are done and try not to get any in your pool.
Any major cracks in the surface of the pool can slow people down (and let the water though). Use a filler on any cracks and let it dry before you use the slide again. A high-quality polish will keep your pool slide slippery, and you should consult a local pool store for the best type of polish to use, and the tools to apply it with. In a pinch, you can take some wax paper and rub it over the slide. This will increase the slickness, but will only last for a short while.