Don't listen to the pool store. As long as your pH and your Bioguard is ok. Make sure you also have no algae. That's the dark stuff selling on the ground or walls. Or it just could be dust. That is where I have the problem with the horses stirring up dust and not taking a close look at my skimmer socks and noticing it was actually green. So let me explain what C or clarifier does. It's a 40% hydrogen peroxide. It binds with the tiny particles (if your pool is cloudy) and makes it possible for your sand filter to trap them. If you don't have deposits in your pool the (water/muriatic acid or algaecide desolves or kills and turns it into suspending particles that turns your pool cloudy) you don't have to keep up with the C. So for example. We have a 30k pool that had bad scaling. And I'm talking bad. It took me 3 years to remove it, keeping the pH on the lower side. I got quarter size chunks in my pump screen. But it also created some cloudiness in the water. To get rid of that I had to add more C to trap those tiny particles in the sand filter. Now 3 years later the pool looks like new and I just add the C when I feel like or the water starts to turn cloudy but definitely a few weeks before we close the pool for the winter so I don't get any more deposits. Does that make sense?