so when i got back into the hobby at the beginning of the year i had several instruments for measuring salinity. i had an old swing arm hygrometer, a small floating glass hygrometer, and one large floating glass hygrometer from wine making. i mixed up a few test batches of salt and they all read *roughly* the same, so i started using the small glass hygrometer for everything since then. while i didn't have many doubts to its accuracy, it did have issues with precision, as surface tension made it hard to be certain of a reading beyond .005 SG.
so I've been seeing some odd things. for one, my calcium and alkalinity seemed to keep rising. after a water change ill have calcium at 520 and alk at 14 .. so i should have precipitation.. but no. after the next water change its 550 and 18, etc. the hard corals seem to be doing fine, but some of the softies (xenia in particular) are not. having trouble growing phyto even though there are no problems at all with the freshwater green water using a similar setup.
so i ordered a refractometer, mostly because i wanted a new toy (not because i thought i needed one). it arrived today, i tested it with RO water and verified it was calibrated, then tested my tank. 1.032 SG. thinking the refractometer must need more calibration i pull out the glass hygrometer and measure - 1.025. so i go back to the RO and verify the calibration, measure again, still 1.032 SG. on a whim, i tap my glass hygrometer on the table upside down a few times and measure 1.027... tap tap tap.. 1.029.. tap tap tap... 1.031.. dang. apparently every time i dropped the hygrometer into the cylinder the paper moved a bit, and Ive been slowly raising my salinity over the past few months.
so refractometer it is
lesson learned. now.. how slowly should i go about lowering the salinity back down to a reasonable number....
so I've been seeing some odd things. for one, my calcium and alkalinity seemed to keep rising. after a water change ill have calcium at 520 and alk at 14 .. so i should have precipitation.. but no. after the next water change its 550 and 18, etc. the hard corals seem to be doing fine, but some of the softies (xenia in particular) are not. having trouble growing phyto even though there are no problems at all with the freshwater green water using a similar setup.
so i ordered a refractometer, mostly because i wanted a new toy (not because i thought i needed one). it arrived today, i tested it with RO water and verified it was calibrated, then tested my tank. 1.032 SG. thinking the refractometer must need more calibration i pull out the glass hygrometer and measure - 1.025. so i go back to the RO and verify the calibration, measure again, still 1.032 SG. on a whim, i tap my glass hygrometer on the table upside down a few times and measure 1.027... tap tap tap.. 1.029.. tap tap tap... 1.031.. dang. apparently every time i dropped the hygrometer into the cylinder the paper moved a bit, and Ive been slowly raising my salinity over the past few months.
so refractometer it is
lesson learned. now.. how slowly should i go about lowering the salinity back down to a reasonable number....