ATO back syphoned, SG dropped!

so i woke up this morning to my return making noise. looks like the head of my ATO line got pushed under the water line in my sump
while i was doing a WC the other day! It back syphoned some tank water into my ato reservoir, while still kicking in a lil bit of water to the sump. so in turn my salinity dropped from 1.026 to 1.024. So i have a few questions.
1. If i plug my ato sensor/pump back in to fill the sump this will lower my SG even further, right?
2. In theory, wouldnt the SG rise back to the original level if i just let the ATO do its thing and kick all the back syphoned water back into the tank?
3. The level in the sump is low now, keeping my skimmer and heaters from working properly, so should i make up some WC salt water w a high SG to add to the tank asap to get it back up to the proper SG and add it to the tank ASAP?
Thanks for your input

 

Since water that got syphoned back into ATO got mixed with whatever fresh water was in there, it's SG is most likely lower than your tank. You can always test SG in your ATO reservoir to be 100% sure.

If it's lower, then obviously letting ATO run without doing anything else would further drop your SG.

What i'd do is mix a fresh batch of salt water at correct SG and add it to sump. That will bring your tank SG up, but not to the desired level.

Then turn your ATO on, and over time, by adding slightly salty water instead of RODI, it will bring your SG back up to desired level. When it's at that level, you should dump remaining ATO water and refil with fresh RODI.

 

You would need to add all the water form the ATO then evaporate all the water that was in there off to get to your original SG. I would bring it back up with a water change. Go slow when changing it, although in your case its not that large of change and hasn't been like that for long.

 

+1 with the guys above.

 

I've had a similar incident. Here's how I approached it:1) mix fresh salt water to 1.026 or 1.027. 2) over fill sump so ato doesn't turn on. You can even disconnect ato. 3) keep sump over filled and test SG over the next few days. As water evaporates SG will slowly rise. When you reach desired sg adjust water level by either adding or removing tank water to appropriate level. I decided that I didn't want to increase the shock by raising salinity too fast. My SG had dropped to 1.023 from 1.025 and I didn't see any apparent effect but it took about 5 days to raise it back.