One of these days I should post an update for the stromatolites setup. It's still doing OK, but it had something of a reset because I found inconsistent accretion of calcium carbonate. I had allowed sand to blow up onto the top stone surfaces because I figured I would see faster growth that way, but what occurred instead was that the sand basically masked those areas. After siphoning and brushing the sand out of the way, I am now seeing more consistent CaCO3 development there. It doesn't really model nature very well, but another trick I've learned is to turn off the powerhead and pour the 5ml capfuls of 2-part so that it settles right on top of the faux stromatolites.
I'm pondering an electronics display to hang on the wall behind the setup. This will just be decorative and not controlling anything in the tank, but will include a clock display for keeping time. This quick Illustrator sketch is inspired by
vintage illuminated aircraft instrument displays. The LED ring, microcontroller, clock display and RTC will be housed in a recessed space and behind tinted acrylic, while the Hershey font illuminated text is flush with the panel face.
I can make that illuminated text by engraving a piece of white acrylic, masking the engrave, then spray painting with black rattle can.
I got a couple of these bright white backlight LEDs that should work pretty nice. These are easy to hook up. You can just power directly from an Arduino pin with a resistor like any regular small LED.
I need to work on that design above some more, Instead of putting all parts together, I might instead opt for the style of enclosures I have used for other projects, but with the drab green and other elements to reinforce the military aircraft idea.