Using acid buffers is not typically recommended. The reason for that being that they typically will cause for a
PH shift sooner or later, and using them in conjuction with weekly water changes is very difficult. First, what type of fish/plants are you trying to keep. Many fish can, especially those raised or born in an aquarium can adjust to an extremely wide range of
ph values.
Maybe you have heard of the Discus spawning in
ph 7.5 water, or the African Cichlid striving at
ph 6.5 . The trick with
ph is not really in initial number, when acclimation is done properly the fish can adjust to whatever the
ph value of your water is. The trick here is keeping that number consistant, and consitancy is what acid buffers lack.
Your
PH of 8.0 does not really rule out any freshwater fish, and only a small selection of plants. If I were you I would either find out what fish/plants can best be kept at your
ph and stick with those, or look for a good source of lower
ph water.