Water Level

The water in my tank is usually right to the rim and my sump is typically filled to the same level. I just noticed the water level in my main tank is down by about 1/8 inch. It's not much but it is strange. The only thing that I know that could cause it would be my HOB overflow box falling down a bit (would be a first in the year the tank has been up). I'm going out of town for a day or two and don't want to come home to any issues! Anything I'm missing?

Thanks!

 

Ok, I just want to offer you some friendly and saving advice regarding your sump!
You DON'T want to have your sump filled as much as you have it!!!! You want it to be down enough so that if their is a power failure etc. the sump doesn't overflow from the water draining from your main tank! That would be a big issue in and of itself!!!

 

My bad, I wasn't very clear. The sump is filled to the "virtual" rim (a piece of tape that I placed on it to denote the max fill line about 3/4 of the way).
Thanks for the advice though, it is important to know!

 

That's cool, just looking out for a fellow reefer is all!!!! Hope all is successful and no problems with your tank while your gone.

 

Now i'm not sure about the whole story...but 1/8 of an inch isn't that much... Do you have an auto top off system or... I'm not really sure I understand the problem.