jmoore

You just need to adjust the pH. Why do you want to use a buffer? A buffer resists pH change, this would be a problem. You can use distilled vinegar and sodium bicarbonate just as easily, why complicate things?

Failing that, drain unblocker is quite often sodium hydroxide (caustic soda) and patio cleaner is hydrochloric acid, but make sure you dilute before use. These items may be available in your local hardware store, just read the labels.