Well, my tank is 30 gallons, with the temp at around 76 degrees F. I have four kribs, three arulius barbs, some neons, and a texas cichlid (2.5 inch).
I'm not sure what the chemistry, but what should i do now?
Well you've covered tank size, but we still need to know the following.
How much light is over the tank? How long is it on each day?
What types of plants are you keeping?
Are you fertilizing at all? If so what, how much, how often?
At a guess, you've probably got standard lighting over the tank which would give you very low light. If you didn't research your plants at all, you probably ended up with plants that can't survive with that little light or they might not even be true aquatics.