Tank level question

[Pennywise the Clown]

My Red Sea Reefer 250 has been up and running for just over a year now. For the first time since I set it up I decided to check the level of the tank since I have borrowed a nice 1m long spirit level.
It is slightly off level. The bubble is still within the lines but not central. I measured the distance between the water level and the top of the tank with all flow off and the difference between front and back is just under 1/8" over the 20" width.
Is this anything to worry about?
My LFS says it is not a problem but I feel a second opinion is warranted.

 

[GThompson]

Not a problem. If it was a 1/4” or more maybe

 

[Sparky88]

If it doesnt spill its fine

 

[BestMomEver]

Should be ok.

 

[Westoncase]

Being level is less important that not twisting. Glass doesn’t twist well.