I used hinged glass doors on a build about a year ago and I am getting ready to do another set on a similar enclosure now.
My issues were like yours; substrate gets kicked up into the tracks and grinds horribly. The monitors aren't too bad, because their substrate is primarily soft coco-fiber/soil mix. My uromastyx are the worse, because I have them on a coarse sand substrate and that stuff will REALLY grind...
My home-made enclosures are relatively large - the one pictured is 60" x 30" x 68" (152 x 76 x 173cm) and the one under construction right now is 48"x 24" x 68" (122 x 66 x 173cm).
The first/bigger enclosure's opening was fairly large, 44"x31" (112 x 79cm), and because I had considered eventually getting slightly bigger monitors, I wanted it to be heavy duty. The second enclosure like this will have similar doors, at about 35" x 31" (89 x 79cm).
I also wanted good quality/high-clarity glass because the enclosure is also decorative.
The size itself drives the glass thickness, because it cannot be allowed to flex. I work in residential construction and had our glazier, a friend who does our glass shelving and shower enclosures, do it for me. Doug made a set of doors using 3/8" (9.5mm) thick glass. He beveled all edges and installed chrome-plated door pulls to open, and heavy-duty self-closing chrome-plated hinges. Because of the size, weight and location of the doors, the glass is tempered for safety.
The thick glass is very heavy. My enclosure is PVC and I had to beef-up the door frame to carry with weight and provide enough rigidity to be perfectly stable.
I am extremely pleased with the result, but even with Doug selling me everything at his cost and installing it for free, it was still VERY expensive and came to almost $500USD for the pair of 22"x31" (56 x 79cm) doors. Most of the expense was in the upgrade hardware and in the tempering cost, but 3/8" thick glass isn't cheap either. A set of doors like this is essentially a custom, high-quality double shower door like we would put in our upscale projects, with the only real difference being height.
I have the second similar enclosure ready to go and honestly, the cost of the doors has me on hold for another few weeks. I am so pleased with the outcome of the first set and want them to match, so I cannot bring myself to do the second set any other way.
The first two pics, Doug is final-fitting the doors prior to taking them down to go to the tempering facility. All drilling and grinding has to take place prior to tempering, so any minor fitting adjustments need to be made now.
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The doors are complete here and standing open:
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The small block in the center of the bottom sill is a stop-block and the self-closing hinges pull themselves closed against this block. Once the doors are open to about 45 degrees, they will stay open on their own.
This system has been in service, open/closed at least a couple times daily, for more than a year, and still works well and looks good. The gaps around the glass and between the panels is 1/8" (3mm) and narrow enough that medium/large crickets cannot escape around the edges of the glass.
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E.T.A.:
I was going to install a latch, but with the relatively small/lightweight Ackies and non-venomous status, I decided the hinge torsion was plenty to keep it closed securely. A latch should be used for a bigger, stronger and/or more dangerous animal.