Science Project: ph level, tadpoles and changing ph levels?

A study found that the optimal ph level for tadpoles is at 6.3. First, I'm wondering why the tadpoles grow best in acidic solution rather than a basic one.

And second, obviously, the ph level in the pond near my house is not going to be at 6.3 so how can i change this? Most likely, I won't have time to drop by once every week to drop a few tablets into the water, so I was thinking of a ';permanent'; solution.

-Just hypothetical but, can bicarbonate help to maintain the ph level at around 6.3? Since it regulates our body ph level. I only know the cycle turns the oxygen or carbon dioxide to bicarbonate and turn it back afterwards? So I'm confused. Could this be a viable solution? Or is there another way?Science Project: ph level, tadpoles and changing ph levels?
dunno