What is the best way to plug and fill a hole on a sand filter? I have a hole where there formally was a pressure gauge thing, but the gauge broke off, and dont want to buy a new one. There is a hole there, and when the filter is on, it shoots water out. I tried filling the hole with powergrab, let it sit over night, still squirts out, but not as bad. The top part is plastic. It is where part #7 on the right side of the image below goes into.