Make A Pond Vacuum Why Did My Fish Die??

Why did my fish die?? - make a pond vacuum

Ok, I'm new all the small aquarium, my man in the house for years, but never too much attention to him and has only minimal maintenance. I have wild hair and decided to try to make the plants look better .... Finally, some fish are dead (and the rest can die) and I try to understand why. That's what I did:

I did a little reading on the internet and found that we could make our CO2 injection by mixing yeast, sugar and water in a bottle of Coca-Cola and the Chain of CO2 into the reservoir of lead that some airlines. Long story short, a little of the mixture composition in the tank (75 liters), due to my ignorance of the emptiness. It began with the production of CO2 in a few hours I went into a drinking vessel capsized as it was aired intor water.

The other is that I have bites plants in the gravel. Reading the website, I suggested to the pool of cheaper locations here instead of chips, aquarium plants.

The next morning we made CO2 and water plant foods is overcast afternoon, which left two angelfish. I do not know what the pH before, but it is now very high (at least 9), after the test strips of the API.

Somebody has an idea of what killed the fish / raise the pH?