NO3PO4-X is from Red Sea. You could also use vodka, vinegar, sugar or vitamin C. Vodka or NO3PO4-X would be your best bet. Just be sure you start real slow.
Here's a search result that'll have plenty of info for you.
You could also set up a refugium, a chaeto reactor or an ATS. These would be my preferred method. They will help balance pH and have many other benefits. I run an ATS but due to light issues it's down at the moment and I'm using NO3PO4-X as a temporary stop gap. For a tank your size, a small fuge or chaeto reactor would have the least impact on space and your wallet while giving you good results.