FYI - GE Silicone II - TOXIC

[uncleof6]

I've filled a tank after 24 hours using GE I. However, I generally don't try to do that, but I have done it a time or two.

Although, I don't think cure time was crabbygirl's issue, it was most likely the mildew inhibitors. But to clarify, she stated GE II is toxic, which may be true, but the results of her anecdote are skewed because she used one with a mildew inhibitor, something we already recognize as toxic. So what should have been stated was that GE Silicone II with mildew inhibitors is toxic, which once again, we already know.

Except for one problem, the "mildew inhibitor" is rather something of a myth, because silicone is mildew resistant already. Advertising trickery. In looking at MSDS information, there is nothing in the formulation that can be traced as being a mildew inhibitor, nor are there any "secret" proprietary ingredients. Silicon spray is used in agriculture as a mildew preventative for grape leaves.

What is clear with certainty, is that ANY uncured silicone, will kill off your tank. The thick silicone beads most often used in aquariums, are not going to cure in 24 hours, maybe not even in 72 hours. Hence we say 2 weeks.

It is all too easy, to use a silicone that is FDA approved for food contact, and then there is no longer a debate over the subject. It seems that the simplest solutions, continually get challenged, and folks want, for no reason in particular, to prove the simple solution is not the best solution--or they simply do not want to admit they did not follow the recommendations.

Sitting on the shelf, right next to the Silicone II, are tubes of Silicone I, FDA approved. Common sense alone says "hey grab the Silicone I, whether Silicone II is toxic or not, whether it has 'mildew inhibitors' in it or not!" The only issue beyond that, is what exactly is the product suitable for, being a consumer grade sealant, rather than an industrial grade adhesive. As long as people keep saying they used silicone II for years, and no issues, and another feels the silicone II killed off their tank, the debate is going to continue.

I won't post the recommendations again in this thread, been posted too many times already.

 

[rrasco]

I agree with that completely. I never tried the methods that give people problems because, well, they give people problems. Fact is, I probably never had issues because I wasn't laying down thick beads.

 

[Khemul]

I think the whole "mold and mildew inhibitor" idea comes from years ago. GE Silicone II used to advertise a special mold and mildew inhibitor in it. As far as I know they haven't advertised that in years but it was at one point a big difference in labeling between Silicone I and Silicone II.

Also while we are correcting common mistakes, "100% silicone" doesn't quite mean what people think. People are commonly told "if it says 100% silicone then you are okay". That just means it is silicone. It doesn't mean that silicone is the only ingredient.



Unfortunately in crabbygirl's case it could well have been the curing process. Silicone II appears to be much less forgiving then Silicone I in that regards. Ideally giving the silicone as much time as possible to cure is best. Silicone I has a much better track record for people who only allow 24 hours. Silicone II seems to be more likely to nuke a tank if it isn't given plenty of time to cure (maybe as a result of the difference curing methods). Granted, as uncleof6 pointed out, any uncured silicone can easily nuke a tank.

 

[jimmyj7090]

It's not just ammonia that gets released, there are other nasties as well.

I can't think of a case that I've personally seen or heard of in which the problem was not "user error."
People take a product that is not designed for the application at hand (meaning pretty much all directions are useless) then follow the useless instructions, then blame the product when problems arise. Simply can't do this and expect good results..

I don't know how many times I've said it, but a week at an absolute minimum for cure time - preferably 2 weeks+ for neutral cure silicones. To do otherwise is risking more and more problems, the user does so at their own risk.. And this isn't just for GEII but *all* neutral cure silicones. Globbing it on thicker and thicker and/or in unexposed areas increases these cure times.

Not trying to sound harsh..just the reality of it..

James

Neutral cure silicone ='s type II. This post explains virtually all of the horror stoires including Crabbygirl's.

Sorry for your losses Crabby

 

[crabbygirl]

Yep, sounds like a total lack of knowledge and experience on our behalf. I'll brush myself off and be grateful that I have a mess of baby seahorses in another tank and restock! Sooooo...the question is, can my live rock be used again after several rinses or is it best to shuck it and start over.

 

[uncleof6]

I don't think any of us can answer that crabbygirl. Short of testing for some exotic chemicals that would be out of the scope of this hobby. Just as with any pollutant, dilution is the solution to pollution. I would want to cook it for a while at the least.

 

[jimmyj7090]

As just about always I agree with him ^

I will say this but take it with many grains of salt....
Yrs ago I made the same mistake and used GE II when putting baffles in a sump, only cured the silicone about 48 hrs before installing the sump. In my case most of my tank seemed to get stressed out and I lost a single clam, but by the time I realized what I had done wrong everything but the clam seemed to have recovered and I ended up leaving the sump in service. As far as I could tell everything was OK from then on. I don't know if whatever nasties were completely gone, or if they were simply diluted enough not to cause any further losses. Whatever the case, I kept my rock and as far as I know there was no long term effect stemming from the exposure to neutral cure silicone still curing.

Whatever you do, of course be very cautious. I would definately run some/lots of activiated carbon on whatever is left of that tank.

 

[crabbygirl]

Okay, thanks for the help! We have rinsed, rinsed and rinsed the rock, since it's the only thing left alive in the tank we'll give it a go. Even the bristle worms and the polyclad worm I haven't seen in 5 years are dead, so I'll be starting new. I'll be running a carbon cannister and some poly filters for awhile and then I'll put in a couple of snails and saltwater mollies in as a test run. I have lost the remaining seahorses this morning and I will count this as one of life's teaching moments

 

[SeedlessOne]

So I'm lost. Why would anyone not just buy the aquarium safe silicone that is sold at hd or lowes? Not sure why even bother with I or II.

 

[rrasco]

So I'm lost. Why would anyone not just buy the aquarium safe silicone that is sold at hd or lowes? Not sure why even bother with I or II.

They typically don't carry 'aquarium safe' silicone in the cartridges for a caulking gun. I've personally only ever seen the small tubes at those stores. It is also usually more expensive if it's labeled 'aquarium safe'. Not to mention you can get a higher quality silicone in RTV.

 

[jimmyj7090]

So I'm lost. Why would anyone not just buy the aquarium safe silicone that is sold at hd or lowes? Not sure why even bother with I or II.

I've never seen a structural adhesive silicone that would be adequate for building a tank at HD, Lowes, or a LFS (all that I have read about silicones re-branded by aquarium mfgs indicates that they are simple sealants and not the stuff that they actually use to build tanks).

 

[uncleof6]

So I'm lost. Why would anyone not just buy the aquarium safe silicone that is sold at hd or lowes? Not sure why even bother with I or II.

This issue has a few facets. The first one is understanding what "aquarium safe" actually means. The second is "what are these products" The third one is anecdote.

"Aquarium Safe" says that the product is FDA approved for food contact areas. That is all it says. It is not an indication of the suitability of the product for the intended application.

What are these products? They are consumer grade sealants. Meaning that they will seal things very well, and that is the extent of it.

Although the labeled "aquarium safe" products are made by Dow Chemical (Both Aqueon/AGA and DAP version,) they are very similar in properties to GE Silicone I, so they can be used interchangeably.

They are all 1-part, Acetoxy cure, 100% Silicone, FDA approved for use in food contact areas.

A word about "100% Silicone"--not all products are 100% silicone. Some are a graft copolymers. One being a graft copolymer of dimethylpolysiloxane and acrylic polymer, the cured product having properties of both silicone and acrylic resin.

Anecdote is what it is. Though the recommendation is very simple and clear, there is never a shortage of well meaning people to argue the merits of altering the recommendation, whether it is a question of cost, convenience, or just wanting to convince others that the recommendation itself, does not have merit. Hence people still grab the tubes of Silicone II or want to build a 240 gallon aquarium with Silicone I--or the DAP/Aqueon/AGA silicone.

 

[Chrome239]

I resealed a 90 about a year ago. Thought I had grabbed 3 tubes of Silicone 1, turns out there was 2 tubes of silicone 2 mixed in. I sealed the tank, waited about 1 month. Filled it, added some corals about 2 weeks later. The corals opened for about 20 minutes and never opened again. Added 1 fish, it was dead 24 hours later.
Spent about 3 days trying to figure out what was going on. Went out to the garage grabbed the caulk gun, and saw the GE2.
Tore the tank down, resealed with GE1, have had no troubles since. The GE2 said absolutely no where on the tube that it contained mildew or mold inhibitors.

Would never recommend GE2 to any one.

 

[chippwalters]

Just had a brand new sump made and used GE Silicon II to attach the drain line and let it cure for 12 hrs before running water through it. I thought it was reef safe based on others experiences (didn't read this thread) and it completely nuked everything in my tank, including bristle worms, all snails and hermits, all fish, all corals and all invertebrates. I hope the $250 I spent on LR isn't lost as well.

I originally thought it was something else and kept doing water changes, thinking I could salvage something/anything. My last fish died today. I'm sad-- and ****ed. FWIW, the title of this thread is exactly true, and just because SOMEONE SOMETIME IN THE PAST got it to work-- doesn't mean others should even try.

Anyone saying GE II is okay to use is like saying its okay for little kids to cross busy intersections because they know one that made it. Just ridiculous.

 

[jimmyj7090]

GE II needs MUCH longer to cure. That's what happened.

Neutral cure silicone is not evil, but it does need it's proper cure time. (IIRC more like a week or two, not 12 hours)

 

[sfsuphysics]

I love me some Dow 795, sticks to glass, acrylic, PVC, great stuff! Only downside is you can't pick this stuff on the fly at Home Depot.