No Mor Problems lasts about as long as your sanitizer. Depending on the pool, you can go up to 2 weeks without treatment before algae begins to appear. You can find more information in the Directions tab on the product page.
So you just got the stains off your pool and it's looking great! But you're worried it's not going to last; as soon as you add something else to the water you're afraid that the stains will come right back. Often when you're finished with a stain ...
As long as you continue to use No Mor Problems the algae should never come back. We back it with a 100% guarantee, so if you get algae open a ticket and we'll help fix it for free.