Question about salinity

[Scottrshoe]

I have been trying to keep the salinity of my tank (20g) at 35ppm. With water changes, it fluctuates +/- 1ppm. First, is this a big deal? What about 2ppm?

Second if my salinity is a little high, as above, can I just raise my ATO fill sensor a little to lower salinity slightly over time, and vice-versa if salinity is a little low?

 

[vetteguy53081]

I have been trying to keep the salinity of my tank (20g) at 35ppm. With water changes, it fluctuates +/- 1ppm. First, is this a big deal? What about 2ppm?

Second if my salinity is a little high, as above, can I just raise my ATO fill sensor a little to lower salinity slightly over time, and vice-versa if salinity is a little low?

Your fluctuation is acceptable
Have you calibrated your tester?

 

[Scottrshoe]

Yes. I calibrated it with RODI water to 0ppm, and with calibration fluid to 35ppm.

 

[Quietman]

I have been trying to keep the salinity of my tank (20g) at 35ppm. With water changes, it fluctuates +/- 1ppm. First, is this a big deal? What about 2ppm?

Second if my salinity is a little high, as above, can I just raise my ATO fill sensor a little to lower salinity slightly over time, and vice-versa if salinity is a little low?

I assume you mean ppt. No, not a big deal. As VetteGuy said, calibration can swing that much (always best to cal before you test). Might depend some on how sensitive your corals are but I've done 34 to 35 corrections at one time with no issues. 2 ppt I may spread out over a couple days, but I may not. My corals have never shown any adverse effects to salinity changes.

To drop I usually just take some out (have a nano as well), and let the ATO take care of it.

 

[Scottrshoe]

Your fluctuation is acceptable
Have you calibrated your tester?

I assume you mean ppt. No, not a big deal. As VetteGuy said, calibration can swing that much (always best to cal before you test). Might depend some on how sensitive your corals are but I've done 34 to 35 corrections at one time with no issues. 2 ppt I may spread out over a couple days, but I may not. My corals have never shown any adverse effects to salinity changes.

To drop I usually just take some out (have a nano as well), and let the ATO take care of it.

Thank You! And yes, I did mean ppt

 

[Randy Holmes-Farley Verified Community Expert]

Second if my salinity is a little high, as above, can I just raise my ATO fill sensor a little to lower salinity slightly over time, and vice-versa if salinity is a little low?

Yes, although salinity shouldn't bounce around if the sensor is at the same height. Be sure you are not chasing test error. Most devices aren't good to better than +/- 1 ppt.

 

[X-37B]

In my 20g nano with Tunze ato the SG is very stable. It runs 1.0265.
I keep it between 1.026 and 1.027 with no issues.
With a proper ato you sg should be very stable even in your small system.