What am I doing wrong? Or am I just being impatient ?

[Aquattro]

You might be better doing a larger water change less often, say 20 or 25g every 2 or 3 weeks. Greater dilution. The skimmer will help too. It doesn't sound like you're in deep trouble, just need to tweak water quality and figure out your lights more. I think they have a dial or something to turn them up and down, not really sure how it's indicated for brightness/intensity.