Silicone yellowed

[jeffchapok]

So I picked up a used 150 gal for an unbelievable price ($350 with stand and all plumbing), but the silicone sealant has yellowed. The tank was sitting dry, so I'm not sure if this is why or if it's due to some other reason. It looks like perhaps it was a DIY job. I'm leak testing it now, and so far so good.

1) Is there anything to be concerned about? I know there is a right and a wrong type of sealant to use. This was last set up as freshwater and running for a year.

2) Is there any way to bleach it back to clear. Ive poured a gallon of bleach in it now and I'm going to leave it for a few days. I'll probably pick up a couple more gallons and add them tomorrow.

I'm hoping that having being submerged again helps it to fade. Anyone else have a similar experience they've dealt with successfully?

 

[Ron Reefman]

Wow! That has really turned yellow. I've seen some get a bit tan but never yellow and NEVER like that! I'd be concerned too.

I doubt it's an age thing. My first suspicion is it's some kind of chemical or medication discoloration. Did you ask questions of the previous owner?

 

[Billdogg]

Wow! That has really turned yellow. I've seen some get a bit tan but never yellow and NEVER like that! I'd be concerned too.

I doubt it's an age thing. My first suspicion is it's some kind of chemical or medication discoloration. Did you ask questions of the previous owner?

Ron beat me to it. If it is just the non-structural inner silicone then it can be carefully removed with a razor blade (well, probably 20), residue removed with acetone and elbow grease, and a new bead applied. If it has discolored the structural portion (the thin bead actually between the panes) I'd be more than a little concerned.

In any case, I'd suggest tossing in some Polyfilter to see if it changes color to indicate a problem.

The only time I've seen anything like that is when, way back in the day, I used so much rid-ich or something that I stained the silicone in my 60 cube blueish. It, however, faded and I kept that tank for 22 years.

 

[TriggerFinger]

That’s bizarre looking...I was not expecting it to be that bright of a yellow. I don’t know anything about fresh water tanks but my first thought was a medication stain too. Good advice up above

 

[skyyyyyyu]

Do you have the guts to use it?
I suggest you delete and paste again

 

[jeffchapok]

Do you have the guts to use it?
I suggest you delete and paste again

I'm less concerned with the staining than I am with trying to remove and reapply it.

You guys have given me an idea though. I might try some blue dye and see what that does.

I added a couple more gals of bleach this morning. I'll let it sit another day or two before doing anything but else.

Thanks for the advice

 

[TriggerFinger]

Has the yellow faded at all @jeffchapok ?

 

[Texas Rick]

That’s odd! I’ve had freshwater for years and that has never happened to me before. I bet it was used for something else with dye and the silicone absorbed it.

 

[jeffchapok]

That’s odd! I’ve had freshwater for years and that has never happened to me before. I bet it was used for something else with dye and the silicone absorbed it.

I don't know that it's only been used for freshwater. The guy I bought it from bought it used himself.

I didn't ask him if it was like that when he bought it because he was offering it so cheaply oh, I didn't want to make a big deal of it. I figured I could either fix it or live with it.

 

[jeffchapok]

Has the yellow faded at all @jeffchapok ?

Not really.

 

[jeffchapok]

It is starting to fade.

 

[jeffchapok]

Getting much better!

 

[Texas Rick]

Getting much better!

That's awesome!

 

[andrewey]

Thanks for sharing this! I had a 40 breeder sump that I bought from another hobbyists years ago with the exact same neon yellow silicone! I tried researching it at the time, but no one had seen anything like it. I was never able to figure out what caused it!

 

[Redfoxtang]

I agree it almost looks like some chemical reaction happened with the silicone and maybe some medication that was used in the tank. Glad it’s starting to fade away though!

 

[jeffchapok]

I'm going to leave the bleach in it until a few days before I'm ready to fill it, just to keep the water from stagnating. But at this point, I'm going to call it a success. I'm going to contact the seller and ask if he knows what caused this. If I find out, I'll let you know.

Now on to refinishing the stand...

 

[ca1ore]

Thanks for sharing this! I had a 40 breeder sump that I bought from another hobbyists years ago with the exact same neon yellow silicone! I tried researching it at the time, but no one had seen anything like it. I was never able to figure out what caused it!

Same! Had this happen in my DIY sump a while back. Never figured out what caused it. Was benign to the tank and its inhabitants.

 

[jeffchapok]

The guy I bought this from told me it was like that when he bought it and he doesn't know what caused it.