Sealant suddenly turned yellow on new tank?

[jeff1733]

Just built a small tank for my office, cycling it at home. Bot some glass & silicone from Glassgages.com (Somaca Clear Aquarium Silicone). Let it cure for about a week, filled with water & sand from existing 75gal tank and let it run for couple weeks. Added some LR from existing tank and within days it turned yellow. Been this way for about 2 weeks. What caused this? Will the yellow leach back out of the sealant? As you can see the sealant under the sand and above the water line is still clear

 

[Randy Holmes-Farley]

I do not know what caused that. Did you add any medications or iron to the tank?

It looks from the picture that only part turned yellow. Was that a different bottle of adhesive? Exposed to the tank water differently?

Anyone seen yellow silicone before?

 

[jeff1733]

Thanks for taking a look. Used RO/DI water from another tank, no chemicals ever added. used 1/2 tube of marine silcone and yea, it's strange its only the silicone that is directly exposed to open water

 

[boxfishpooalot]

I had the same thing happen to my sump! I found out what the problem was before, but cant remember....I do know that it does not weaken it or anything.

Im thinking that when it was exposed to rain outdoors and sun, did the trick somehow making the cure yellow?

Or maybee its absorbing nitrates!! :lol:

 

[46bfinGA]

same thing in my sump.the color does not go away if your bothered by it you will need to remove the silicone and re install it.im not sure what caused it in mine,im thinking to short of a set up time,or something in the silicone reacting to the salt water.hopefully someone can jump in and give us the reasoning behind this.i used ge silicone 100% in my sump

 

[boxfishpooalot]

I used ge 100% also. . But I changed my sump so its not yellow anymore. I too think that I was impatient and did not let it cure long enough before contact with saltwater.