Nitrates and phosphates - Red Sea NO3:PO4-X

[Treebeard]

Contrary to my previous results and thanks to using expired test kits, I discovered that my nitrates and phosphate levels are actually sky high.
In an effort to reduce levels, for the past 5 weeks I have been doing 50% water changes and nitrates are still steady at 40 ppm and phosphates at .08. My skimmer is a Vertex IN180 and is working well.

I am considering trying Red Sea NO3:PO4-X and was wondering if anyone else has used it with success?