As Rick said I wouldn't do chems yet either.(oooh..flashback) Problem solving is a big part of the hobby IMO. That said I have a couple questions if you don't mind....

Do you have a skimmer?
You say your maxed out on livestock...what do you have in there?
Have you tested your nitrates? (lazy snails)
What is your feeding regimen?

Try not to get discouraged. This can be fixed, it's all about import/export