Hi, this is Kevin Bird from Swimming Pool Safety Solutions. And, today's topic is, "How do I tell if my swimming pool filter sand needs to be replaced?" Basically, there are a few different types of swimming pool filters. There's a sand filter, which I just mentioned. There's also a Diatomaceous Earth or a DE filter, which is what we have here. And, in all filter's there's going to be a pressure gauge on the top of the filter system, which tells you what the pressure is inside of the filter. Basically, when the filter is clean, it will give you one reading. For example, let's say it's at 10. When the pressure on that gauge goes up between eight and 10 pounds, in other words, if we started at 10, when it got up to 18 to 20, it will be time to clean that filter. Anytime the pressure goes up by eight to 10 pounds from its clean, operating pressure, it should be cleaned. When the filter is taken apart and cleaned, what we will normally do, the pool guy, is we will take a marker, and put a mark at its clean operating pressure, so that we'll know when it's gone up eight to 10 pounds, without trying to remember. That's the best way to do it. Just put a mark on your filer gauge. When you see that it's gone up eight to 10 pounds, it's time to take this thing apart and clean it again. Also, the same for your sand filters. Sand filters, you won't take apart as often as you'll take apart a diatomaceous earth filter. Sand filters, you'll mostly just backwash to get the filter clean, and maybe take it apart every couple of years, compared to a diatomaceous earth filter, which you might backwash once or twice a year, and take it apart once or twice a year. This has been the topic of "How do I know when it's time to clean my filter or clean the sand in my sand filter?"