220g tank seam discoloration

[bean0tis]

I recently purchased a tank second hand. the tank is about 7 years old. water tested it and it held water fine. I noticed when i purchased the tank the interior silicone was starting to peel away in a few places. Drained the tank, I scrapped out the silicone, cleaned it properly and resealed the inside. I never got the razor blade in between the planes of glass. I used SCS1200 - about 3 tubes. The new internal seal is about a half inch thick and used a caulking tool to get a nice thick bead all around. i let the caulking cure for a week before filling the tank.

Last night i noticed a cloudy colour in the caulking of the primary seal in between the 2 panes of glass. it doesnt appear to be the usual air bubbles forming when the seal starts to fail. im not seeing any real separation. theres nothing at the top, it grows to about the middle point and then tapers back into nothing again.

anyone know what this could be? should i be concerned?

pictures below.

 

[Timfish]

Hard to say just off those pics. One guess is it has something to d with the way light is being reflected and refractes inside the glass. Yuoo might try putting somthing inside the tank to shade part of the joint to see it the apperance changes.

 

[Jekyl]

Anywhere you tried to use new silicone over the old is not going to hold. Not sure which chemicals are used in silicone, but maybe some leeched into the old and caused a reaction.

 

[Jekyl]

@Joe Glass Cages any insider info to help?

 

[Joe Glass Cages]

@Joe Glass Cages any insider info to help?

this is a tough one @Jekyl

our specialty is in building new tanks. When we make the decision to reseal a tank, it is a total tear down, hyper cleaning and then re-assembling.

looked at the pictures. Hard part here is we dont know the history of the tank, who manufactured the tank, how the tank was treated and maintained, how many times it was moved, how many times it was sold and on and on.

My first thought is, the silicone was not cured enough. we require the tanks to be curved for 3 weeks before filling if the tank is 25" or shorter and 4 weeks if 31" and taller. those are my first thoughts but I am really not sure.