I have a 25 gallon cube in my office at work. It is a Mr. Aqua tank (18" all around) and I have an AI Nano light and MP10 for flow. It has been in operation since April of this year. I had been slow about adding fish and coral the first few months, but as time passed started to dabble a little more. I added a few small acro frags in mid June to the tank. After a few weeks of adjustment period, they all seemed to start growing well and really coloring up. And then out of no where, one started RTN'ing followed by another. I love the look of the acros and would like to keep them, but I think I am struggling with keeping all my parameters where they need to be (especially alkalinity). Any suggestions on how to get this under control? I do 20% water changes every other week. Thanks in advance.