Aquarium silicone sealant comparisons


MFK Member
Dec 13, 2018
The Sunny San Joaquin
Real Name
Retired computer bum
I did not read this entire thread but I do have a few comments, having designed with silicone for many years.

I designed systems in which cut stone was applied over steel frames using silicone adhesive and sealant.

I worked as an engineer for a company which manufacturers glass and aluminum glazing, storefronts and aluminum doors. I designed glazing systems which relied on silicone, and there are many high-rise buildings using such systems.

One of the projects I did an engineering study for was the infamous Biosphere habitat. There was a Biosphere-1 and a Biosphere-2 design, and you can look them up online.

It was initially determined that biosphere one was too small and it was enlarged about 25% to create the Biosphere-2 plan. If they had enlarged it by 2000% the project might have been successful.

Like an overstocked aquarium the Biosphere crashed without completing a full cycle. In other words it could never be self-sustaining because too much methane was created inside and not enough oxygen.

Ultimately our company did not take that contract because the client demanded a 100-year guarantee on what is essentially a glass, silicone and aluminum dome, applied over a welded steel frame.

You will find that the project failed and was closed out long before the 100-year guarantee, not because the silicone leaked, but because it was so tight there was Zero air exchange and the people inside were suffocating.

To be honest, it was supposed to replicate a habitat on the surface of Mars, so the entire thing was glass but you could not open a single window.

They were trying to test a totally sealed dome environment with people, animals and crops inside.

But just like an aquarium, it was the bacteria to be the downfall! As they broke down organic matter and wastes, gases were created that could not be contained or dealt with, and certainly not breathed.

ANYHOW . . .

GE Silicone-1 was specified and normally this came with a 20 year guarantee, though over the years that guarantee was increased to 25 and then 30 years. But this client demanded a 100-year guarantee and General Electric signed that, with provisions including that there was a full-time on site continuous inspection of the cleaning and sealing.

Accelerated aging tests had been done in the past, which convinced General Electric that they could offer this to a particular client under a particular situation.

Of course every engineer involved in the project knew that it would not run anywhere close to 100 years. For the University to get funding for just a two-year program was nearly impossible.

Cleaning is a vitally important in this business if you want a seal that lasts a long time. It is in fact the most important part of the entire business.

I have one new tank sealed with GE SCS and one I resealed with GE Silicone-1. It was only done one year ago so no guess on the long-term durability of my repairs. The SES tank was done at the same time.

Anyhow GE Silicone-1 is the thing to use in my mind. I'm sure you can spend more money but I don't think you can buy better as it is pure 100% silicone.