Reef Safe Silicone

john08007

New member
I think I know the answer but just want to put it out here to check. As far as a reef safe silicone I can use any 100% silicone that does not mention any kind of fights bacteria, antimicrobial or anything like that, correct??
 
I think I know the answer but just want to put it out here to check. As far as a reef safe silicone I can use any 100% silicone that does not mention any kind of fights bacteria, antimicrobial or anything like that, correct??

You can use any silicone you care too, as there is no such thing as "anti-mildew" additives. Silicone is naturally mildew resistant, and neutral cure silicone is more mildew resistant. (Silicone II is a neutral cure silicone same as the much recommended Dow Corning 795.) After pouring over hundreds of MSDS and product data sheets, I have yet to find any component of a silicone product by any manufacturer that would be considered as anti-anything.

What kills tanks is insufficient cure time. Silicone (whether Silicone I or Silicone II, need to cure a minimum of a week, and considering the globs used by hobbyists, 2 weeks and sometimes longer.

In short, all silicones (except those containing co-polymers e.g. not 100% silicone) are reef safe. It is the end user that is not reef safe. ;)

This leaves the appropriate question: What silicone is best suited for my purpose. Silicone I and silicone II, despite widespread usage, are not suitable for marine system use, nor are any other consumer grade sealants on the market.
 
Uncle, I think you are saying n the last line that silicone 1 and 2 are not suitable for a marine tank. Did I read that correct? I'm looking to put baffles in a 20g tank to build.a sump.
 
Uncle, I think you are saying n the last line that silicone 1 and 2 are not suitable for a marine tank. Did I read that correct? I'm looking to put baffles in a 20g tank to build.a sump.
John, don't mind Uncle, he often posts conflicting information (at least in these past few days he has) to better his position. Frankly the whole tone of his posts are rather irritating already, like his opinion is the only right one.

I personally have used GE Silicone 1 - Windows & Doors with no issues thus far, this came at great recommendation from 3 friends and the LFS shop owner who have been keeping reefs for many many many years.

I would trust their judgement over someone on the internet any day :) but don't take my word for it. :fish1:

Being in the construction business I can assure you that Silicone 1's would be safe, as long as they are allowed to properly cure, and by cure I don't mean what it says on the bottle, I mean a week at the minimum just to be safe. What ends up being the deadly factor with these Silicones is the off gassing into your tank. Ever wonder why the smell burns your nostrils when working with it? Can you imagine the fish having to breath that in.

Companies like GE don't endorse their products for aquarium use because they don't want to be held accountable for any failures or liability claims. Just make sure it doesn't have the mildew inhibitor in it and you'll be fine (GE II, etc).
 
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The RTV100 series is very good stuff and can be found in black (RTV103) if desired. It costs a bit more than the GE but I know a lot of DIY people use it for glass aquarium building.
 
John, don't mind Uncle, he often posts conflicting information (at least in these past few days he has) to better his position. Frankly the whole tone of his posts are rather irritating already, like his opinion is the only right one.

I personally have used GE Silicone 1 - Windows & Doors with no issues thus far, this came at great recommendation from 3 friends and the LFS shop owner who have been keeping reefs for many many many years.

I would trust their judgement over someone on the internet any day :) but don't take my word for it. :fish1:

Being in the construction business I can assure you that Silicone 1's would be safe, as long as they are allowed to properly cure, and by cure I don't mean what it says on the bottle, I mean a week at the minimum just to be safe. What ends up being the deadly factor with these Silicones is the off gassing into your tank. Ever wonder why the smell burns your nostrils when working with it? Can you imagine the fish having to breath that in.

Companies like GE don't endorse their products for aquarium use because they don't want to be held accountable for any failures or liability claims. Just make sure it doesn't have the mildew inhibitor in it and you'll be fine (GE II, etc).

I don't think I've ever seen anything conflicting from uncle. He hardly seems warm and fuzzy, but if I wanted a hug I wouldn't come to an internet forum. He has said the same thing about the various silicone products on the market dozens if not hundreds of times. They'll not kill your tank once cured, but you get a very poor bond with GE1 compared to other available options. Thus it isn't suitable for a marine tank in his opinion, even if it isn't unsafe in a chemical sense. Seems to me that it'd be worth spending the extra few bucks to buy a tube of a better product even if you'd probably get away with using the cheaper stuff.

That said it's your tank. Use whatever you like, and take or ignore any of the advise you asked for.
 
wow, quite the debate for a simple question...

GE 1 100% silicone. Great for baffles on a sump but never to seal a tank. Let it cure for a full 7 days and you'll be good. I've done it several times and it lasts for years.
 
I have used Ge silicone one for several years in reefs, FOWLR, fresh and terrariums, after 96 hrs I never had an issue, cheap to get and use, Just would never use it to build a n aquarium due to lack of strength in bond, better RTV out there.
 
The guy I had helping with occasional tank maintenance leaned on my coast to coast overflow on my 220 and broke the vertical silicon seam that holds the overflow against the back of the aquarium. So I need to fix this, but obviously the tank is full and I can shut the return pump down for a week to let the silicon cure... Any advice is appreciated. Thanks Phil
 
The guy I had helping with occasional tank maintenance leaned on my coast to coast overflow on my 220 and broke the vertical silicon seam that holds the overflow against the back of the aquarium. So I need to fix this, but obviously the tank is full and I can shut the return pump down for a week to let the silicon cure... Any advice is appreciated. Thanks Phil

Out of curiosity, was the overflow glass, or acrylic? If acrylic, you just found out why I keep harping on the fact that silicone does not bond to acrylic, and you need something better than junky GE I. If it was glass overflow, it was not installed properly: Simply leaning on it should not have broken it free...

That said, there is no way to repair it without draining the tank down to a level where the silicone will not come in contact with the water, until it is fully cured some week to two weeks down the road. Sorry, just the way it is. There is no other bonding material you can easily use, save for uv catalyzed polymers, (proprietary when it comes to aquarium use) but you would still need to drain the tank down to do the repairs. You cannot do anything with it under water.

Incidently, it is time to find a new person for your maintenance needs...
 
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