Adding Rocks that are found in my back yard?

[ewurm]

It could have a button for 20% water change, add chlor-out, meds, etc. BOMB.

 

[Princley]

Its more of a cinderblock that broke off. How long would it take for it to dissolve and produce too many chemicals, possible turning the water to acidic?

it will raise the PH a bit about 7.5 . many out door ponda are made of brick and cement.... i know a pond filter that usees cement to seal it in, one of the very best pond filters i have even seen

 

[ewurm]

Yep, cement raise pH.