# Bio Seal, Great Stuff and Egg Crate! OH my!



## topaz017 (Jul 30, 2006)

Ive been reading the boards for about a week now. I'm new to this hobby and will be setting up my new tank shortly. I've read, and read, looked at many other sites, and read more. Ever since I saw the dart frogs 4 months ago at a pet store here in San Diego, I've been hooked.

I have 3 questions, I haven't or have seen answered but not what I was looking for. So as my first noobie post, here they are!

1. Bio Seal in Silicone - I can't find any GE II without it, I've looked and I don't really want to pay 7 bux shipping to get the old stuff without Bio Seal. I read the post that said people haven't had problems. Any more input on it? Id hate to start up a tank, and make this mistake, and have my poor froggies dead and not know why. Id hate to think it was this additive in the Silicone. Has any long time frog keeper noticed any problems? I've seen so many mixed responses on this topic. I'm thinking, I should just go with DAP products I've seen people said were food safe.

2. Great Stuff - Oh boy, this stuff scares me. So many chemicals! Its so perfect for these kinds of applications. But will it break down in 2 years? What If while covering with silicone, I miss a tiny spot? If water is in contact with it a lot, will it poison the tank? 

3. Egg Crate - I found a sheet of it at the lighting dept at my hardware store. I assume this is what most people use? Seems a bit thin? What I got is about 1/4 inch thick. Is there something thicker? I will use the PVC pipe under it for support, but worry long term about it breaking down under the weight.

I thank everyone in advance. I look forward to your thoughts and advice!

Shaun


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## defaced (May 23, 2005)

I'm not sure what you have or haven't read about Bio seal, so I'll give you the scoop. About 6 months ago, this lable started showing up on GE's Silicone II products. Because we're weary of any mold inhibitor (like what's in the kitchen and bath silicones), this sent up a red flag. Some people decided to abandon using Silicone II at this point in time, others continued to use it, and a few people called GE to get the story on Bioseal. The people who called (two of them to my knowledge) reported that the GE people said that it's always been there, it's just not being marked as such to improve product sales. The people who continued to use the Bio Seal silicone haven't reported any problems. In short, there's not been enough evidence in any direction to make a decision as to if it's safe or not. Silicone I and DAP products are still an option. 

Great Stuff is a polyurethane plastic - it doesn't break down. The only thing I've ever read that can effect GS is UV exposure, and that just changes its color. The chemical list you're seeing in the MSDS is what is in it before is cures. After it cures most/all of that stuff has reacted off. I urge you to do a search for a thread called "A conversation wtih Dow" or something along those lines. The other thing to consider is that GS has been used in literily thousands of tanks with the longest reported use being around three years. If a problem was going to show up, there is a very good chance it would have showed up by now. 

Yes, egg crate is thin. Make sure that the egg crate is supported every 6-9" and you won't have any problem with it. The stuff bends alot before it breaks.


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## topaz017 (Jul 30, 2006)

Wow... Search for Dow... never would have thought.. duh!! Thank you!

So after reading that, I think Ill go with the DAP food safe stuff.


A new question has raised... Does the silicone peal off GreatStuff easily? Does sandpaper/sanding the edges work well to keep it stuck on? Anyone tried that?


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## JBR (May 8, 2006)

I used silicone on my Great Stuff and had no problem with peeling (I had the same concern) It holds pretty strongly. If I remember correctly I let it cure for about a week.

John


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## defaced (May 23, 2005)

Does silicone peel off great stuff, yes. Will it in our application... I don't know. So far it's done a find job of holding up the 10ish pounds of rock on my 25gs background. To see what you think spray some GS on a piece of card board, let it cure, put some silicone on it, let it cure, and then try to peel it off.


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