Not sure if the new Salifert test kit instructions changed, but there is a high range and low range test you can run with Salifert. Low range would be the one you want to run to see where your CArx Effulent is at.
I don’t use salifert test kit but to test my calcium reactor effluent, I file up the vial half way with RODI water and other half with effluent from reactor. Test the results and then double the Alk reading. So when I do this test my results may be 12 dKh. Doubling that means my effluent is 24 dKh.
I use the Salifert alk test and I just fill the syringe twice and add the measurements together. My effluent runs about 25-26. To achieve this with my MRC 2 reactor my bubble rate is 60 per min and effluent rate is 40 ml per min. I have a heavily stocked DT and frag tank.….and I still have dose sometimes to keep my numbers in check.