So I have a biocube 29. It’s been up and running since 2013. Currently it’s just a coral tank for me. One yellow coris wrasse which has been in less than a month. Two pieces of rock with Zoas on them smaller than a dollar bill combined. And one decent size piece of rock with some gsp. I’ve never had a nutrient issue until a few weeks ago. I typically would change 5 gal every 2-3 weeks. About a week or two ago I noticed my phosphates crept up to almost .3 (nitrates stay between 4-6). I’ve done a 5 gal change every 2-3 days for the last week and phosphates have gone down but seem to hover around .21-.24. Any suggestions on lowering them? I’d ideally like to see sub.1. I was hoping I could accomplish this either with a larger water change or multiple changes over a period of time.