Silicone Going Bad?

TheFishman9000

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I’m pretty sure I know my answer, but posting anyway. I recently decided to restart an old tank (about 7-8 years d) that has been sitting with stagnant water in it for roughly four years. Doing my water change today, I noticed my silicone in one corner looks different from the rest. Upon closer inspection, I saw what appeared to be old algae or detritus between the glass and the silicone. Also, if I look for another angle “into” the glass, I see what appears to be air where the algae/detritus would be. This is a Marineland 90 gallon tank 48x18x24.

Is my best bet to start looking for a replacement tank? I’m not sure how I would go about resealing this one with how big it is.
IMG_8361.jpeg
IMG_8359.jpeg
 
The silicone bead inside the tank is primarily there to protect against over-enthusiastic scraping, thankfully!

However, I do see several spots in the actual glass:glass structural silicone seam pictured above which could potentially be of concern, and merit more detailed photos (ideally under whiter lighting!)

Namely, these areas:

IMG_2025.jpeg
IMG_2026.jpeg
 
The silicone bead inside the tank is primarily there to protect against over-enthusiastic scraping, thankfully!

However, I do see several spots in the actual glass:glass structural silicone seam pictured above which could potentially be of concern, and merit more detailed photos (ideally under whiter lighting!)

Namely, these areas:

IMG_2025.jpeg
IMG_2026.jpeg
IMG_8373.jpeg
IMG_8374.jpeg

IMG_8375.jpeg

Here’s some whiter light on those areas plus an area up toward the top
 
IMG_8373.jpeg
IMG_8374.jpeg

IMG_8375.jpeg

Here’s some whiter light on those areas plus an area up toward the top
Oh wow! That center photo shows algae has ingressed to the air bubbles! This tank is a ticking time bomb!

I recommend draining the water immediately!

I actually had my tank shut down for an extended period with no water movement, and my rock never did have a full bacterial die off! — if possible, stick the rock in a temporary holding bin/container made of plastic with tank water to keep it alive! (Restarting from sterile rock is very tedious!)
 
Oh wow! That center photo shows algae has ingressed to the air bubbles! This tank is a ticking time bomb!

I recommend draining the water immediately!

I actually had my tank shut down for an extended period with no water movement, and my rock never did have a full bacterial die off! — if possible, stick the rock in a temporary holding bin/container made of plastic with tank water to keep it alive! (Restarting from sterile rock is very tedious!)
Shoot, glad I noticed it at least. In theory, could I go and buy the exact same model, swap everything except the sand into the new tank, and then start the pumps like nothing happened? I have another 55 gallon that can be used to temporarily store the current inhabitants.
 
Shoot, glad I noticed it at least. In theory, could I go and buy the exact same model, swap everything except the sand into the new tank, and then start the pumps like nothing happened? I have another 55 gallon that can be used to temporarily store the current inhabitants.
In theory, you could!

You’d really want to check the stand for water damage, and settling out of level before filling the new tank up… the seam bubbling can actually be caused by the tank trying to twist on a stand with a high or low corner!

but, otherwise, a direct replacement definitely works!
 
In theory, you could!

You’d really want to check the stand for water damage, and settling out of level before filling the new tank up… the seam bubbling can actually be caused by the tank trying to twist on a stand with a high or low corner!

but, otherwise, a direct replacement definitely works!
I will definitely be confirming everything is level before I fill the new tank.

Last question (promise 😂): I obviously don’t want to reuse my old sand here. If I get a new bed of caribsea aragalive and put it in the new tank, you think there would be any issues with my cycle or other harm to my fish/coral? I can’t think of any other than some cloudiness. This whole thing has me stressed out/paranoid now. Just trying to cover my bases!
 
I will definitely be confirming everything is level before I fill the new tank.

Last question (promise 😂): I obviously don’t want to reuse my old sand here. If I get a new bed of caribsea aragalive and put it in the new tank, you think there would be any issues with my cycle or other harm to my fish/coral? I can’t think of any other than some cloudiness. This whole thing has me stressed out/paranoid now. Just trying to cover my bases!
Good question! I don’t think new sand will have an appreciable adverse effect, assuming you thoroughly rinse it prior to adding it to the tank!

The bagged “live” sand isn’t particularly beneficial, or particularly live… that said, you might be better off getting crushed aragonite and just heavily washing it!

(The technique I’ve always used is sticking all the sand in a bucket, and running a garden hose at high flow, sticking the hose end in the bucket of sand to fluidize the sand and stir it up until the water runs off clear! This can take a good amount of time, like 3-10mins, depending on the sand!)
 

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