What silicone is safe for an aquarium?

[src]

Some of you may have seen my posts on another thread. The gist of the situation is that I used some GE Silicone II Door and Window (without the anti-mildew additive) in part of my aquarium. I've been told that I should have used GE Silicone I, not II. Reading the II container, it does say not for use in aquariums.

So, off I go to Lowes, only to find that there are 2 different types of Silicone I on the shelf. One of them (Rev. 0101) says nothing about aquariums. The other (Rev. 0305) says not for aquariums. Other than a labeling update, there doesn't seem to be any difference between them. No "new and improved" statement, or any indication that something has changed.

So, I'm left with 3 possibilities. First, none of the GE Silicones are safe for aquariums, and they just didn't have a warning on the earlier labels. Second, they made a change to the forumation between 0101 and 0305, and the early one is safe but the later one isn't. Finally, regardless of what it says on the tubes, both 0101 and 0305 are safe, but GE is covering their keisters with the fine print.

So, does anyone really know, for certain, based upon real data, that Silicone I Rev 0101 is safe? Does anyone know that Rev 0305 isn't? And finally, do we know that Silicone II is not safe, based upon anything other than the label?

Obviously, if I were to re-do my silicone I would buy a known safe aquarium silicone. The price difference isn't enough to create a fish killing environment just to save a few bucks. Also, obviously, I would prefer not to have to break down my entire 125G setup, plants and substrate to replace the Silicone II if it is safe.

So, the question is, what do we know for a fact, and what is just word-of-mouth advice?

 

[JRagg]

I'd go with what everyone KNOWS is safe.

I'm like that though. And I know I didn't answer your question. I'm kind of like that too.

 

[joannde]

Still researching but I found this (had to use the cached version so I hope the link works)
http://cc.msnscache.com/cache.aspx?q=3593984412363&lang=en-US&mkt=en-US&FORM=CVRE

quote:
"Which product can I use in my aquarium?

GE does not recommend the use of our CONSUMER products on aquariums. The Silicone II product line releases ammonia as the by-product of cure. The ammonia can change the pH of the water in the aquarium having a negative impact on the marine life. "

So GE is saying none of the consumer products should be used. I'm still researching - will post more if I find more


EDIT: from this GE website
http://www.geadvancedmaterials.com/...port/FAQDetail/applicationquestions.html#faq7

quote:
Can I use silicone in my pool, whirlpool bath or boat?
We do not recommend any silicone for any constant underwater use because over time the silicone bond to the substrate can fail.

my comment : sounds like "CYA"

 

[src]

OK, I've done a LOT of reading since I got home. Right now, it appears as if the reason to avoid GE II and not GE I is because of anti-mold/mildew and anti-UV properties. Fortunately, not all GE II has these properties. The tube I bought is labelled almost the same as the tube of GE I Rev 0101 that I found, with only slight varitions in the table that shows how well it holds various materials.

Tracking back through the history of this topic (going back more than a year), it appears that when GE II was introduced to the market, either only the Bathroom/Kitchen version was out or all versions included the mildewcide. Since then, it appears that they have released a version that is more pure. However, the "common wisdom" has not moved, because everyone already "knew" that you shouldn't use GE II. In my lay opinion, the version of GE II that I got (Door and Window, clear, without any of the mold/mildew/UV protection) is essentially the same as the GE I that everyone recommends.

Even then, the opinion was that the mildew/mold control might be a problem, and it doesn't appear that anyone had any hard data to back up the assertion (although I don't believe it to be false).

However, since the GE I appears to have gone through a revision (label only or formula is anyone's guess), then the conventional wisdom on that product will have to be revised anyway.

The fact that GE II releases ammonia during the cure is a non-issue for me. My tank is cycling, ammonia is part of the process. The very small amounts released by the silicone in my tank shouldn't be an issue.

As far as it not holding in underwater applications, there is no stress on it now. The forces being applied are pretty evenly balanced, so that's a non-issue too. The fact that some people have been building tanks with GE I helps put the lie to that issue too, but there is a possibility of failure down the road. I think people would be well served by moving to the "real" aquarium silicone products in the future.

If it sounds like I am trying to convince myself to not worry about it, it's because I have already done so. I don't believe that the GE II I used is going to be any more toxic than the GE I everyone has been recommending. I probably won't be using either one in the future, but barring anyone chiming in with hard data I won't be tearing down this tank to replace what I have already used. If nothing else you guys now have a guinea pig in the field testing the issue.

 

[BillD]

The facts are, that for decades, people and manufacturers have used GE Silicone I for building and sealing aquariums. Apparently there are stronger versions known as (I believe) RTV 1200 and RTV 1600, with the 1600 being stronger, than 1200, and 1200 being stronger than Silicone I. There is strong belief, that the AGA silicone is rebrandeed GE. Personally, I use Mastercraft Silicone for doors and windows. It is a house brand for Canadian tire stores, and says "ideal for aquariums" on the tube. It is made in the US, and I would be surprised if it wasn't GE.
If you look at the last quote above, (pool bath, or boat) in no case is glass involved. Silicone does not bond to plastics the way it does to glass.
As far as Silicone II goes, GE claims (on the tube) it's bonding strenght to glass is as strong or stronger than Silicone I. I did see a post on a forum, where one guy did an informal strngth test, and felt the II wasn't as strong as the I. Other than, than the fact that it is an ammonia cure rather than acetic, I can't say whether that is an issue, nor have I seen anything definitive with regards to that.

 

[src]

Thanks, Bill. I (and I'm sure others as well) appreciate the additional information.

 

[BillD]

If you ever notice anything amiss, src, that might be related to this, I for one, would like to hear about it. It is an area that seems to be inconclusive, with regards to silicone.

 

[src]

Well, right now there are so many things that could be the source of problems with this tank, it will be hard to nail it down to any one source. I'm _still_ fighting a battle with the soap from the bad ammonia. I just can't bring myself to throw out $200 of eco-complete, so I'm still flushing soap out of the system. Amazing how much was in just a couple of caps full of ammonia.

But I will certainly keep everyone apprised of any results.

The good news is that the plants are still alive, and there are plenty of snails crawling around that came in on the plants, and they seem to be thriving. Go figure.

 

[Toirtis]

GE touts its 'Silicone I' and 1200 series as being approved for aquarium use and construction, and they are all I have used for years. The 1200 series also comes in black.

 

[src]

GE touts its 'Silicone I' and 1200 series as being approved for aquarium use and construction, and they are all I have used for years. The 1200 series also comes in black.

I didn't check the 1200, but the new cans of GE I (check the small print for REV 0305) now say that it is not safe for aquariums. It's easy to tell the difference, because on the old container (REV 0101) the word "Clear" was in a black triangle, and the new ones say "Clear" in a white triangle.

Had me more than a little confused when I was looking, because I first picked up one of the new versions, and it clearly indicated that it wasn't aquarium safe. Then I found an old one, that didn't mention aquariums at all. That's when I found the different revision numbers - they are in the very last block of text on the label, under the spanish instructions.

 

[Toirtis]

I didn't check the 1200, but the new cans of GE I (check the small print for REV 0305) now say that it is not safe for aquariums. It's easy to tell the difference, because on the old container (REV 0101) the word "Clear" was in a black triangle, and the new ones say "Clear" in a white triangle.

Had me more than a little confused when I was looking, because I first picked up one of the new versions, and it clearly indicated that it wasn't aquarium safe. Then I found an old one, that didn't mention aquariums at all. That's when I found the different revision numbers - they are in the very last block of text on the label, under the spanish instructions.

Ours comes in tubes and has no Spanish....

I go by what the GE silicones and sealants manual and site says.

 

[src]

Sorry, yes it was in a tube (caulking gun tube). You probably have 0101. I'm just saying be careful, since they have either changed the formula in 0305 (which could be a problem), or have just made a labeling change (which would be OK).