jharn

I just checked my salinity again after calibrating the refractometer with Pinpoint Salinity Calibration Fluid That I ordered from BRS. It’s a 35 ppt solution and after adjusting the refractometer my tank reading was 36 ppt. My tank is a RS Reefer 350, which has a total volume of 91 gallons (display=73 gal; sump=18 gal). I’d estimate the net volume, less rock and sand, to be about 80 gal. Any suggestions on how best to reduce the salinity are much appreciated.

Thanks for the advice. I checked the refractometer this morning and it was definitely off. When I zeroed it with RODI, the tank salinity was closer to 1.028. Sounds like this might help explain my high alkalinity values. I’ll look for the calibration solution you recommended so I can get a more accurate reading. Lesson learned, for sure.

I try to keep the salinity around 1.026. I use a refractometer that I got from Bulk Reef Supply. Is calibration just a matter of zeroing the scale with RODI, or is there more to it? I haven’t been doing that, so will calibrate it today when I do a water change.

I have a RS Reefer 350 tank with a variety of soft corals and a couple of fish. I’ve been having a hard time managing my alkalinity and nutrient levels. I‘ve been doing weekly 15% water changes for the past couple of months but today’s alkalinity test showed 14.2 dKH using a Hanna tester. Calcium is consistently around 480 mg/l using API test kit. Magnesium is around 1425 mg/l. I’ve always used Instant Ocean salt, but just got some Red Sea salt (Blue Bucket) and am planning to start using that in the future. Anything else I should try to bring the alkalinity down to the usual 8-12 range? Would it help to add some LPS or other hard corals? I’m concerned about the high alkalinity, even though the soft corals seem quite happy. My NO3 levels have also been high (>24 mg/l). I’ve been dosing with RS NoPox for the past 6 weeks and the nutrient levels are finally starting to drop with today’s NO3 level down to 4 mg/l. PO4 is 1.7 mg/l, while pH is 8.5. Seems like the NoPOx is working, so will be tracking nutrient levels carefully to bring the NO3 down to around 1 mg/l.