Quick pond armor/shield question

[THE FAMILY GUY]

Definitely searched Google before asking here but couldn't find a definitive answer.

I want to go bare bottom on one of my 180 gallon glass tanks but I'd prefer to have an all black bare bottom. I'm wondering if pond shield/armor used for plywood tanks would work on glass? If not any suggestions on getting the inside bottom panel painted all black? Also curious about flex seal paint.

Also I don't want to flip the tank and paint the outside because of the brace and also it wouldn't look as neat. I'd prefer painting the inside bottom panel.

 

[jjohnwm]

Coincidentally, I had an unfortunate experience with this idea. I had a DIY plywood tank made using a slightly different method than typically used. The glass panel was siliconed directly to the interior of the unpainted plywood, the interior was then painted with Pond Shield, and finally an interior sealing bead of silicone was applied around the edges of the glass. My sloppy application of the Pond Shield had resulted in areas where it extended onto the edges of the glass, still invisible from the front of the tank due to the width of the plywood frame around the window. When the final silicone bead was applied and smoothed, there were a few spots where the epoxy extended out past the edge of the bead.

After a few months in service, the tank developed a leak in each of those spots. Water insinuated its way between the epoxy and the glass, which allowed it to get under the sealing silicone bead and reach the bare wood. I eventually gave up trying to repair that tank; it became a reptile cage afterwards.

When examined, the spots where the epoxy peaked through the silicone could be easily flaked away with a fingernail, taking large sections of silicone with them. I think that a bottom coated with the stuff would be very susceptible to damage from aquarium decor or even from enthusiastic use of aquarium tools for cleaning.

A bottom covered with ceramic tiles, carefully cut to fit closely together and provide complete bottom coverage, is IMHO much nicer. I've read posts where people fret about gunk under the tiles, anaerobic conditions, etc. but I've had tanks outfitted this way running for a decade or more with no issues.

I tried a smaller tank with a bottom covering of snap-together waterproof "luxury vinyl" floor tiles and it seemed to work okay; test fish survived in it for over a year with no apparent ill effects. That tank had an 80-90% water change at least weekly; not sure how a less-stringent water change regimen would work with that set-up, and never really pursued it any further.

 

[THE FAMILY GUY]

Thanks a million for the reply. Didn't think about the epoxy and the integrity of the silicone. I did tile years ago but I definitely had a detritus farm underneath the tile when I removed them. I'm sure I was a few centimeters off with my cuts. Not sure what to do at this point but I need to figure out something

 

[jjohnwm]

To clarify...there is no issue with the silicone adhesion to cured epoxy; that's the typical construction technique I have used many times with complete satisfaction. And the epoxy definitely won't adhere to cured silicone, but that doesn't matter for this application. The problem was with the epoxy adhesion to the glass, which was, after a fairly short period of time, non-existent.