I have had a 55 with the black sealant for almost 10 years, but I never noticed it until I came here and people mentioned it. I don't find it too distracting, obviously.
What are you trying to research? We might be of more help than a non-existent website.
I just want my planted tanks to be perfect. Is that so much to ask?
55g: (Mostly) African riverine species: Alestes Chaperi, breeding pair of Kribs, and rhino pleco
30g: Newly established reef tank
10g: Planted but fishless
5g: Unplanted with various snail species
2.5g: Heavily planted with betta.