What's your rodi
testing at ? You like to see under 2 ppm
Have you got a phosphate test kit yet ?
When you bought the tank it was up and running ?
Was it crashed ?
Your rocks could be leaching phosphates to?
Sounds like the same situation I got myself Into ! Ask lots of questions! Use this forum, people on here are always willing to help and have helped me over time fix my tanks ! Just do what people tell you and they won't steer you wrong !
Best thing I ever learned about this hobby is go slow ! Don't rush!