We have a regularly use full bathroom in the basement that uses a sump pump to remove waste water. For the last 5 years, it has ran fine after every flush and shower use. Recently, for the last two months, (problem 1) the power of the sump pump doesn't sound like it use to, sounds like it is struggling to pump water. (problem 2) it is taking longer to pump water than usually. (problem 3) sounds like there are rocks in the sump pump when it is removing the water. The container is sealed and I'm not sure how to open it. Please help, thank you.