black/brown dots in aquarium silicone

[anthony]

so my silicone has the little brown/ black dots in/under it at first there was just a few so I didn't mind, I thought it was just algae . I don't want to scrub at my seals but now that there is a lot of dots it looks kind of ugly. After closer inspection the dots seem to be under or in the silicone and won't come out. Is this algae or mold? Is this going to destroy the seal? How do I get rid of this or prevent it from happening? Thanks

 

[DMD123]

Over some years I have had small bubbles form in the edge of my silicone and a little bit of algae grows in it. It will go from green to brown over a bit of time.

 

[anthony]

well since the dots wont come out they seem to be growing under the silicone. Will they destroy the seal????????????????? And what is the part of the silicone that is holding the tank together? Is it the part that squished in between the glass or the 1/4 inch line that runs on both sides of the seam?

 

[Anonymous]

I thought glass was held together by an epoxy glue of some sort and the rim. And the silicone was just sealing it from leaking. I have a ton of this growing along the edges of my silicone.

 

[anthony]

I thought the trim held the tank together until they started having rimless tanks. Then I heard the trim was just to keep it looking nice. If the trim were holding every thing together the important part of the silicone would be the part in the crack? not the 1/4 inch border running up and down the glass?

 

[anderson_p_r]

My understanding is that it's the combined strength of the silicone between the panes and in the inner dimmensions of the tank that hold it all together.  The silicone is surprisingly strong and after having to reseal my 45g it really was tough to scrape it all out.  The silicone has quite the bond to the glass and if you think about the total length of the bonded edges the pressure is spread pretty evenly.  The bottom frame's primary purpose is to keep the bottom pane off the stand to elimate the need for a perfectly flat and even supporting surface.  Top frame is usually just for looks, unless it has a cross brace, and even then I had an old 55g with a broken cross brace it was fine for many years, I eventually sold it.

As far as the algae is concerned, I've owned and seen some tanks with some knarwly silicone that were 100% water tight. My 45g looked perfect until I filled it and it leaked. I would run your finger nail allong the edge of the silicone seal in question and see if it feels snug on the glass or if it feels as though it's lifting. I also recently helped a friend reseal their 29g that the seal was lifting about 1/2 way. It was still water tight but they were concerned. We did the reseal while switching substrates.

 

[Anthraxx]

my big tank has the same issue, just seems to be the silicone shrinking over time and allowing a little water behind there which in turn grows algae. not really concerned about it as its just overspray to cover their bases. the structural support comes from the bond between the panes themselves. gl with it ive had some success cleaning it off mine but id rather let a sleeping dog lye rather then go messing with it.

 

[anthony]

Thanks guys! I'm not to worried about the looks. I'm more concerned about the algae growing under the silicone and seperating it from the glass, since the tank is in my living room

 

[kb0961]

i would definitely be concerned about algae growing under the silicone.

It means that water is getting under the silicone, which means the silicone wasn't properly sealed, which means you run the risk of your tank giving out. Now that doesn't mean that it will give out today. It could take years or it could take days. there's really no way to tell until it happens

if you want peace of mind, i would look at getting the tank resealed properly.

and yes, the silicone holds the tank together, not the trim. The only part of the trim that provides any structural support is the center braces you see on the larger tanks. Those center braces help prevent the tank from bowing and cracking the glass due to the pressure of the water

 

[bronzefighter]

So I'm seeing a lot of misinformation here, so I'll try and clear it up. This only applies to glass aquariums that are held together with silicone and that's it.

Today there are 3 aspects holding an aquarium together. The first is a thin bead of silicone that is sandwiched between the glass panels. This is what provides nearly all of the structual integrity and waterproof seal. This layer rarely has a problem. The second is another layer of thin silicone that is smeared along the inside edges and corners. This layer protects the first and reinforces the water-proof seal. The third is the rim. The bottom rim on most tanks simply elevates the bottom panel to prevent any sort of uneven stresses on the glass, while the top is generally used to keep the glass in place while it is siliconed together. It's also used to cover up the unfinished edges of the glass panels in an effort to save money. For the most part, the top rim provides little to no structual support, and many people have removed it to create a (ugly) rimless aquarium.

Now as far as resealing goes, if there is significant degradation, then I would look into resealing it. But it's pretty typical for that thin layer to separate and bubble up in a few places.

 

[DMD123]

This whole issue is why I miss my old tank that came standard with black silicone. I have a few little spots showing on my clear but it was invisible with the black. Or just go acrylic and not have to worry.

 

[bronzefighter]

This whole issue is why I miss my old tank that came standard with black silicone. I have a few little spots showing on my clear but it was invisible with the black. Or just go acrylic and not have to worry.

 :iagree: 

Though acrylic has it's own set of problems too  :| :|