Glass or Acrilic lid?

[fizzy]

i build acrylic aquarius and i would say use glass for a lid, yes the acrylic will bend or bow due to heat from build up in the tank or from lights BUT acrylic does not soak up water it cant due to its construction it is not a porous material, i have been working with acrylic for 20yrs.

D

 

[Pharaoh]

im not doubting you... how old are they.. ive yet to have this issue..

They have to be at least two years old, if not older. I'll get some pics as it is really bad on a few.