I am new to this site. I am currently establishing a 72 gallon bowfront all glass aquarium. I am planning on stocking the tank with African Cichlids. I have seen many tanks with Texas Holey Rock in them. How do you safely stack these rocks together? Do they just sit on top of one another? I don't want to lean them against the back glass of my aquarium since they would scratch the glass. I will have to add a few at a time due to the cost of this stuff! Also is it ok that the filter tube is behind the rock?
Thanks for any help u can give me!!

I have 100 pounds of holey rock in my tank and yes they are just stacked on top of each other and none are touching the glass. you can also epoxy them together. As far as the filter tube it is fine behind the rocks as long as there is enough space back there for it to do it's job.

Thanks for the comments on my site. I also stacked my Texas holey rock ( I got 62 PBS @ 3.49 per lb.) I still have one piece I did not use. 60lbs. Should be plenty for your tank. It did help having it all upfront, I was able to stack it all before adding water, plants, fish, etc but it is expensive. I did not use epoxy although I heard that was an option. My fish are 1" to 1.5" so they do not move rock or plants around much yet, but I hear when they get bigger,that can be an issue. Just keeping placing the rock so it fits snug and seems stable. I'm looking forward to seeing the finished product.

Just so you know, holey rock raises your ph because the rock is made of limestone, probably a good thing since A. cichlids like a high ph.