We sell a vinyl inground pool kit, with the attached resin step sections. Using a step section attached to the pool is much easier and cheaper than installing our vinyl-over-step kit, but some customers can develop stains on the pool steps.
The first step to removing vinyl pool step stains is to try and determine the cause of the stain - is it vegetable, mineral or animal? Remember that game?
Vegetable Stains: In this category is the stains from leaves, mulch or algae blooms. You may have noticed the stains after a heavy rain storm, or after cleaning the steps off. A vegetable stain can be an all-over stain as well, as when a pool sits full of leaves and turns the color of iced tea. Or it can be isolated stains in the corners of the stair steps or just at the waterline.
Vegetable stains, and all organic types of stains, can be removed with good old chlorine, instantly. But, you do not want to toss chlorine granules into the pool and possibly damage the liner. For an isolated stain, you can sprinkle Cal-Hypo on the steps, or pour small amounts into a 2" PVC pipe, and slowly move the pipe over the pool steps. If you are able to lower the water, you can use bleach or Clorox granules to scrub the steps clean. If the stain is an oily waterline stain on the steps (and other parts of the pool), use a pool enzyme to consume oils.
Mineral Stains: Calcium, in hard water areas, likes to come out of solution, mix with dirt and oils, and deposit itself onto steps as a gray or brown-ish discoloration. You may notice this in conjunction with a high pH level, or after shocking the pool. Metals can also come out of solution when conditions allow, staining steps a slight brownish-orange hue from iron, black-ish for magnesium and blue-ish for cobalt.
Mineral stains can be removed by first balancing the water with proper pH and Alkalinity, and Calcium Hardness in the 150-350 ppm range. Use a sequestering agent to lock up the minerals, or even better - use CuLator to remove them, and then use Jack's Magic Step Stuff. Another useful product for vinyl pool step stains is Stain Free, made from Ascorbic acid, it won't hurt your liner.
Animal Stains: Animal stains on pool steps is usually worms. Most other animals float (yuck) into the skimmer, or will sink into a deeper area of the pool. Worm stains on pool steps or on the liner can be safely removed with EZ Stain Remover, or with Stain Free, mentioned above. You can also use a small amount of chlorine pool shock (on the pool steps, but not on the vinyl liner).
In Summary; like all other pool stain problems, the first step is to balance the water, unless you want to drain the pool to the bottom step and scrub the pool steps by hand with a chlorine-based cleanser.
When keeping the pool full, Step Stuff and Stain Free offer almost a sure-cure to pool step stains, but be sure to follow directions with regard to application, and more importantly, follow the water balance instructions closely.
SPP Pool Expert