Moldable silicone putty - aquarium safe?

[Luananeko]

Ok, so this is for a freshwater aquarium rather than a reef, but all the freshwater forums I used to visit appear to have hardly anyone using them anymore. I have some 3D printed tunnels that will be under my sand against the glass that I want to seal so the sand doesn't leak down into them, but I still want to be able to remove them later if I redesign the aquascape or need to clean out the tunnels without breaking down the entire display tank. I found this moldable silicone putty on Amazon that seems perfect for filling any gaps between the tunnels and the glass: Amazon product

Does anyone know I can test if it's aquarium safe? It says it's waterproof and made of silicone, but I figure it has to have some other ingredients to keep it pliable...

 

[shakacuz]

i figure regular aquarium silicone/sealant would suffice for this. this being "moldable" is likely just a gimmick

 

[Luananeko]

i figure regular aquarium silicone/sealant would suffice for this. this being "moldable" is likely just a gimmick

But if I use regular sealant I have to drain the tank fully and let it dry out if I need to pull any tunnels for cleaning/maintenance... And I am NOT confident in my ability to use regular sealant to seal the tunnels in any sort of aesthetically pleasing way. Something like putty I can take my time and poke and prod it with my fingers to shape it exactly how I need.