Agreed, that looks fixable but you need to find out why that happened in the first place. Check for level and examine the stand as wellYou should get some acrylic solvent and try to reseal it.
What are the dimensions? How thick material? How long has it been like that? Did it just appear or did you first notice it a long time ago and it’s getting bigger?Well its almost did. on my 600 gallon by Tenecor. View attachment 1351051View attachment 1351052