for most aquarium salts i would recommend about 1 tsp to every 5 gallons. for the most part this has worked for me. what size tank do you have? do you have a filter on the tank? if you have a filter that is big enough for the tank you have, that should produce enough air without needing an airstone. Now Guppies are typically top swimming fish and just because they are swimming to the top doesn't necessarily mean that the water doesn't have enough oxygen. is your tank heated? Guppies are tropical fish and need a tank that is heated between 72 F and about 76 F
happy owner of a wild type GFP axolotl named Percival and too many guppies to count.
Last edited by DragonFyre14; 08-20-2012 at 02:56 PM.