RODI chemical levels

[nihadmajid]

Should any RODI water with a TDS of 0 have any calcium in it. Below are my readings for RODI. My calcium is very high=600+ in my tank. So I have tested water at all 3 levels.
TDS = 0, pH=6.3, NO3=0.1, PO4=0.00, CA=200, Alk=0

 

[kgross]

Your RODI water should have zero calcium in it. If you are reading 200ppm CA in your RODI water I think your test is off.

 

[kharmaguru]

Should any RODI water with a TDS of 0 have any calcium in it. Below are my readings for RODI. My calcium is very high=600+ in my tank. So I have tested water at all 3 levels.
TDS = 0, pH=6.3, NO3=0.1, PO4=0.00, CA=200, Alk=0

If TDS is zero, you can't have 200ppm calcium or the TDS would be 200. Are you using a marine calcium test for the freshwater? Is the test kit expired? I would venture to guess that your salt water is actually at 400 calcium.

 

[nihadmajid]

Thanks for the input. I am using the new Hanna Marine Master Multiparameter Photometer HI97105. It comes with calcium reagent A HI7581U and then reagent B HI7582. The dates are good through end of 2024. May be the meter calibration is off.

 

[nihadmajid]

I figured it out. Thanks for all your help.

 

[JohnL]

I figured it out. Thanks for all your help.

Share what you found please.