how level

[randymon]

ok finally got my new 125 set up sat and now that its full it seems to have settled and left side water level seems to be almost 1/2 inch differance. Is this something I need to take care of right away or should I watch and see if it settles more? front to back is ok.

[Ninong]

If there is 1/2" difference in your water level between the left side and the right side you have a VERY SERIOUS PROBLEM that must be addressed right away before you do anything else.

This could cause the tank to fail by putting too much stress on one side. The rule of thumb for professional aquarium installers is that there should be no more than 1/8" difference in water column height from left to right or front to back.

Maybe I was just lucky but my 120-gal tank has no difference whatsoever in the height of the water column left to right or front to back. I carefully measured the surface of the stand with a level in every conceivable direction before installing the tank and then I measured the top frame of the tank in every possible direction before beginning to fill it with water.

[randymon]

OK. Can I shim it full or do I need to completley empty and will it be ok till the weekend? Also is there a correct way to shim.

[Ninong]

OK. Can I shim it full or do I need to completley empty and will it be ok till the weekend? Also is there a correct way to shim.

I'm not the best person in the world to answer this question, so hopefully someone else will chime in. I just know it's something that needs to be corrected.