low salinity need some advice
 

I do my tank top ups manually with my ro unit. My gf plugged in the ro unit forgot and left for work. I now have a wet floor and worst of all my salinity has dropped to 1.017. Does anyone know how to safely raise my salinity up again?

remove water and add properly salinated premixed water.
or add salt slowly to sump but get rid of the excess water.
they key is SLOW change.

best bet would be to do a water change and bump the salt content up slowly. How is everything doing? That is pretty damn low!

Slowly bring it up with water changes. I usually just go .001 or .002 more with my 20% water changes. Not sure if you can slowly drip a high concentration of saltwater... Like with some tubing and a valve set to a slow drip.

raise it by .001 every 3-4 hrs until you get to your ideal salinity.

I added 5G of higher concentrated water and brought it up to 1.018. Surprisingly my sps still have polyp extension. Only sign is one of my sps has faded in color a bit. This is going to be a long night.

Looks like you've got everything under control. Another suggestion would be to put some fans on the tank to speed up evaporation and let the evap slowly raise your salinity. Top up with saltwater until your salinity reaches target.

thanks everyone it's all good now.