I have the deltec phosphate test kit, it seems to be getting the job done and my tank reads 0.008 or 0.015 depending on when I test. Good enough for me and its in line with the hanna meter when I get my water tested at OA.

For the most part, I still believe that what caulerpa is in my tank is still sucking up most of the phosphates. Its ok though, my fish eat it pretty quick and what is living in there is towards the back of the tank. Out of sight out of mind I say :wink: