I have two albino corys, one Julli cory and two emerald corys. They are in a 55 gallon with one pangasius cat, a pearl flowerhorn, a pleco, a banjo cat, and a spotted green puffer. Everyone gets along very well. The corys love to school together and you can tell the albinos are a pair - they are always together.
A pH of 7 is neutral. A pH less than 7 is acidic. A pH greater than 7 is basic. The pH scale is logarithmic and as a result, each whole pH value below 7 is ten times more acidic than the next higher value. For example, pH 4 is ten times more acidic than pH 5 and 100 times (10 times 10) more acidic than pH 6. The same holds true for pH values above 7, each of which is ten times more alkaline (another way to say basic) than the next lower whole value.
On the pH scale, which ranges from 0 on the acidic end to 14 on the alkaline end, a solution is neutral if its pH is 7. At pH 7, water contains equal concentrations of H+ and OH-ions. Substances with a pH less than 7 are acidic because they contain a higher concentration of H+ ions.