We had a hail storm yesterday, and the hail broke the glass on the gauge on my Hayward sand filter. The sand filter appears to still be working but it doesn't go down to 0 when I turn the pump off now, and the pressure reading doesn't go down much after backwashing. The pressure reading is also abnormally high. I've never replaced a sand filter gauge before so I'm wondering if someone can give me instructions on how to replace it. I also need to know if it is okay to continue using it in its current condition until I have time this weekend to replace it.