Natural Chemistry Extra Strength Stain Free, 1.75 lb, Single, Removes Metal Stains from Pool Liners & Finishes, Compatible with All Sanitizing Systems

I owned a pool service company for 4 years. This stuff always saved me with my customers, and keeps my pool crystal clear, here in NC the water (city) has a good bit of iron in it that stains all pools. This stuff (ascorbic acid) makes the iron release. Combine this with a C-Ulator pack and it will get the stains out until the next time you have to “top up” your pool with the hose.

Purchased before. Excellent product. Works well in the pool.

In a word: Amazing. I had severe calcium silicate deposits on the entire deep section of my Vinyl pool. This was a relatively new liner and I was considering replacing it. I tried many products and brushed it rigorously for weeks. This product dissolved it within minutes of application. It removed 100% of the hideous stain and it literally looks like it did when installed. I was in complete shock. After trying Scaletec, muriatic acid, lowering PH, and nothing even scratched the stain. This product eliminated it within minutes. Again, Amazing. Looks like new now. Picture is from before and shows the issue I had.

This product works! We have had great results using it.

It helps with the brown stains in the pool but I had to use for bottle. It did not help with black spots.

I had stains on side of in ground fiberglass pool the entire perimeter of the pool from neglect over the winter months. Stains were a brownish green and probably 2-3 feet in height . I scrubbed, used magic eraser...bleach. No luck. I seriously thought I would have to get pool resurfaced as nothing worked. This stuff is truly a miracle. Simply poured it in close to the sides and on steps and within 3-4 hours...most stains gone(I honestly could so the stains fading before my eyes as soon as I poured it on the walls of the pool directly). By next day completely clear and pool back to original blue. It did cloud pool a tiny bit but once I shocked the pool and ran the filter 24 hours.....it was clear as can be with zero stains. HIGHLY RECOMMEND. I would image it would do same job on fiberglass hot tubs and boats as well.

Following a refill after a repair, my white 11k gallon fiberglass pool turned solid brown in color. It was terrible, and after trying a bunch of different products I finally bought Natural Chemistry 07395 Extra Strength Stain Free. I simply added it to the pool, ran the pump for 15 minutes to 'stir' and then left it over night. The change the next morning was beyond remarkable - The pool is sparkling white. Your mileage may vary, but I am so pleased that I tried the product as I had almost given up. You will need to bring your chlorine back up slowly over the next couple of days as the treatment will flatten it. Also remember to clean your filter before the process and regularly for the next week. Some additional thoughts - - This works on metal stains, and you can test for that by buying some Vit C tablets from your drug store (white, crushable). It the stain fades when you rub a tablet on the pool wall then this product should work. - It will begin working immediately - My steps and floor near the pool walls cleared in 5 minutes - but it takes time for it to work across the entire pool. I ran the pump to mix the treatment in, but that was not something they stated in the instructions. - My pool was heavily stained so I used the entire treatment. - The 'after' pictures are the next day, about 24 hours after I added Stain Free. - Although there is nothing in the product instructions I have read that rapidly raising the pools chlorine and alkalinity can drop the metal back out of solution. I have raised it more gradually without issue over a few days. - $30+ for what is basically 2lb of powdered absorbic acid (Vit C) is expensive - You can buy an 8lb tub on Amazon for less than $60. If you don't think you will need to do this regularly then it is probably still worth it (I would have paid double, and I was quoted $300 by a pool company for basically the same thing). If you are in a high iron area and need to refill often then you can do better volumewise with your $.

This stuff really works! We have hard water that was staining our pool, and after trying this, it brought our pool back to its original color. Super happy and will definitely buy again if needed!

used for removing metal staining on the whole of a pre-formed pool. excellent.