IS the bottom totally supported with Styro? If it is the patch is more likely to be sucessful. You can't use acrylic as the silicone doesn't stick to it all that well.You could double up the 1/4" by laminating 2 pieces together to give you 1/2". Another option if the tank sits on styro is to patch both sides. As long as the bottom can't flex, a patch should work. We had a local store that had a 700+ gallon tank that had a crack
ed bottom, and it was repaired with a patch.
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