Quote Originally Posted by Mentat View Post
Hi, just want to add couple simple thoughts. 1st thing is to buy new light bulb/s. If fluorescent tubes; they start losing lumens around six month mark and by 1 year many are producing 1/2 the lumens they did as new. Only light elements you do not replace are LEDs.

Second thing is your aquarium pH of 8. For tetras in general, a pH of 8 is a bit high. Do you know what was pH before starting to add the CO2? If adding CO2 raised the tank pH abruptly; it could explain the death of first Tetra. Also, if store had 2nd Tetra in neutral to acidic water; it probably died of pH shock when released into highly alkaline water. Sadly, Tetras don't handle abrupt pH changes well .
Yes! I think you may be right about the pH.
I posted this exact post on tropical fish forums, and that was their main concern...
My tap pH is 8.0. I can't figure outhow to lower the pH? I've tried several products.
The suggestion on tropical fish forums was to re-home the tetras and then get more alkaline, hard water tolerant fish...