This are plugs that will last for over 100 years in water, I called and verified with “Cement Mix†Safe for ponds after cure, no toxic chemicals, 9000 psi after 28 days, this plugs are super duper strong “FORGET ABOUT ITâ€. You must let them cure before introducing to the aquarium for at least 45 days.
Step 1 make the forms
Step 1 make the forms