Questions on Caulking

I recently bought some caulking to do a slate bottom tank for my axies. I just wanted to check with the experts to see if this caulking was suitable for my guys before i went ahead with the project. I bought Dynaflex 230 aluminum gray. DAP Products - Caulks and Sealants - DAP® DYNAFLEX 230® Premium Indoor/Outdoor Sealant Thanks for your help.

You might like to private message Sludgemunkey (Johhny) or Jennewt (Jen) to seek their advice in this. They are the King and Queen of DIY tanks and vivariums and the best person to ask.

The only DAP product currently safe for submerged use in aquaria for caudates is DAP product 688 Household/Aquarium sealant. All others now have additives to prevent mold and bacterial growth or have petroleum distillates added (As of Dec. 2009 when they changed their formulas). This makes them dangerous for submerged use with caudates. (Keep in mind that some of them are safe for use with fish or in dry set-ups but that is a whole other topic...)

From General Electric, product M90008 (GE Ant Sealer 100% silicone) and GE012A (GE Silicone I window and door) are the only two products that are free of additives dangerous to caudates.

Of the products listed above, only the DAP 688 is rated for structural projects, like aquarium repair. The other products listed are safe to use as adhesives for what you describe.


IMPORTANT NOTE: When I state "dangerous for aquatic caudates" or the like, the sealants/adhesives themselves are not dangerous. I have been unable to find and valid evidence that the additives are dangerous to caudates either. Where the danger comes from is the anti-mold and mildew additives will kill off nitrifying bacteria in your tank. To put it simply, you will have one heck of a time cycling the tank properly. This will result in bad water chemistry which will ultimately lead to disease and or death of your amphibians.

I just make sure it says "100% silicone." Johnny, but do you really think microbial inhibitors in the glue would affect the whole tank? I'm just guessing, but I think it might inhibit mold/algae from growing on the actual glue, but the whole tank, after a little while, I could hardly imagine it would be that strong. I think if it even did work for a little while, these inhibitors would be overpowered by the sheer multitude of the bacteria that grow in a tank. But that's just my guess. Did you ever try it?

Thank you sludgemonkey for your input. I Decided to use this product to put a slate bottom on my tank. I was thinking about what otterwoman said and was just wondering what you thought about those comments. It does seem logical that the bacteria would overpower the "mold and mildew" additives. Considering there can be no more than 5 percent caulk exposed compared to the surface area of the slate. However, when I bought this product I did a side by side comparison with the GE I caulk and the only difference is that the DAP product is paintable. The product description checklist did not say that it was anti mold or mildew. Any more information or opinions would be great thanks

Ps. I have my axoltols in a temporary tank (cycled) until there remodeled home is completely sealed and dry. I will put half of the cycled water into their new tank and monitor the levels for at least a week before i put my guys in there.