reducing salinity and increase mg level

mrtian97 · Sep 4, 2017

Due to uncalibrated refractometer, my salinity drifted to 1.030 from 1.026. mostbof my sps are fine, just lost 4 frags. I have swapped out 5 gallon with RODI (system around 85 gallon) on Saturday. that brings the salinity down to 1.028. Since then, I am swapping out 1 gallon RODI per day (2nd day) but still showing 1.028.

Questions:
1. based on different read, seems I will need to swap out a total of 6.3 gallon RODI to bring down to 1.026. Should I just do the 1 gallon per day swap or is it safe to do it the same day? I worries with the other items like Ca, Alk (my alk hovers between 6.5 to 7). I have increased the alk dosing to compensate the swap. My Ca is at 400

2. For Mg level, for some reason my Mg is at 1200 (used to around 1300-1400). I read that due to impurities concern, I don't want to dump 1,000 mL in one day. I been doing 160 mL per day, this will take me around 10 days or so to reach 1400. Would it be safe to have the mg level this low for 10 more days?

Thanks

Randy Holmes-Farley · Sep 4, 2017

Yes, swapping out 1 gallon per day is a good plan. If you have time available, I'd do 1/2 gallon twice a day.

Yes, raising the mag slowly is a fine plan, although I'm not sure you need to go that slow. Note that the mag rise will also boost salinity.

mrtian97 · Sep 4, 2017

Thanks Randy. I ran out of my mag test solution (Red Sea), hope to get the new one by this coming Friday. Will I be able to hold off in dosing more mag until I get to test or continue dosing high amt. I am not sure how my mag dropped by that much if my salinity is high.

The good news on salinity, after I calibrated my ATC refractometer with the 35 ppt solutuon, currently my salinity is 1.026 (this after swap about a total of 7 gallon RODI the past 3 days. I was calibrating it with RO water to 0 value , I forgot that with BRS, they include the calibration sol. So my salinity was not as high as I originally thought (I think it was 1.028).

Lastly, with the Alk, I am using Randy's 2 part and I was dosing 215 mL per day (throughout the day), and since the issue with salinity and swapping with RODI, my alk seems to drift down to 6.5. I increased the alk dosing by 50mL per day to 265mL. Would this be an issue?

Thanks

Randy Holmes-Farley · Sep 5, 2017

mrtian97 said:
Thanks Randy. I ran out of my mag test solution (Red Sea), hope to get the new one by this coming Friday. Will I be able to hold off in dosing more mag until I get to test or continue dosing high amt. I am not sure how my mag dropped by that much if my salinity is high.

Probably testing error. Magnesium can't suddenly drop.

As long as the demand in terms of dKH per day seems reasonable for what is in the tank, increasing the two part dosage can be increased.