I'm replacing my 1.5 Gal DIY kalk dripper with dual 5 gallon DIY kalk dripper. I'm using two 5 gallon plastic water bottles to hold the kalkwasser. I'm using a John Good RO/DI bulkhead in the bottom of the water bottles, but it turns out that the bulkheads don't seem to be meant for submerged use. Water leaks around the outside of the plastic tubing. I plan on using some silicone sealant around the tube on the inside of the water bottles to keep the water from leaking through the bulkhead. Is silicone safe to use with kalkwasser? I just want to make sure the high PH of kalk wouldn't be a problem.