Has anyone ever used a concrete patio block in their sump to raise up the skimmer? My question is a concrete block safe for a fish tank? I need to raise my skimmer an 1 1/2 inches and one of those would be perfect. I just want to make sure the concrete block isn't going to put any thing in the water that would cause problems down the road. If anyone has used or try this let me know. Thanks.

