Resealing 120g - nail biting!

[aravind90chan]

I bought a used 120g reef ready set up and it looks like it might need resealing. My finger nail can flick the silicone near the top of the tank. I would like to remove the flaps and reseal (not rebuild i.e. I will only reapply silicone and not take the entire tank apart) it for safety. I will do a leak test but the previous owner says that it holds water.
How difficult is it to reseal a 120g tank? I have experience in wood working, electrical circuitry, plumbing etc but have no clue about resealing a tank.
Planning to use a grouting tool kit to remove the silicone and reapply black aquarium silicone forming a 1/2" seem (10mm glass) on each edge.
Please give me advice and suggestions.
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[Sturiosoma]

That looks like Liz's kind of tank, just kidding,

you can take a razor scraper and scrape up to the seam removing as much silicone as possible and cleaning good before reapplying

Jeanne

[aravind90chan]

Is there a lot of room for screw up?

[Sturiosoma]

No I've done it before just lay your razor scraper flat on the glass and work into the corner , say from the back glass into the corner of the side glass and then you can even take a razor knife and get in the corner and cut out some of the silicone just don't do any prying and sometimes you can pop the top rim but if it doesn't come off easily leave it alone , this is time consuming but just take your time and you'll be ok

Jeanne

[brady]

I would not use black silicone. It most like likely contains additives ,coloring,ect. that could be harmful to the fish.
If you notice, any commercial tanks and most if not all hobbyist tanks are constructed with clear silicone.
GE #1 clear is pure silicone sealant. A lot of the others are mold resistant, colored, ect. Not for aquarium
use.
Jay

[ref0716]

Black silicone was the "in thing" for some tank makers not so long ago. It is probably still available through specialty aquarium retailers. Stay away from the stuff at Home Depot etc... HTH

Richard

[AquaticNerd]

Black silicone is entirely safe provided you get the correct product. I would not trust the stuff from big box stores such as Home Depot and Lowes - mainly because my searches turned up silicones with additives that I would not trust in an aquarium. However, you can get a product like this Black Silicone from Amazon (https://www.amazon.com/Black-Aquarium-Silicone-Sealant-Cartridge/dp/B00EZB2MDI?th=1) for resealing and it will work just fine. I personally like the look of black silicone over clear for aquariums because it doesn't get stained like clear can.

With that said, you will want to make sure that aquarium is spotless before applying a new seal. For reef tanks, I like cleaning all the deposits and such off using oxalic acid (commonly known as Barkeeper's Friend). Completely fish safe and rinses clean - similar to vinegar but around 1000x stronger (less elbow grease) and really takes care of all that dried up gunk. After everything is clean you should then be good to go scraping off the silicone and applying new. I've done it a few times - here's my tips:

1. Only scrape what's visible - the silicone holding the glass together should not be touched, so I would avoid scraping between the glass. If you're using a razor blade, make the blade parallel to the glass and scrape up and down. An example of this would be to put the blade as parallel as possible to the back glass, press in towards the side glass, and then slide the blade up/down until you've reached the side glass. Repeat for all sides.
2. After the silicone is removed, clean up the areas where the silicone was with some 92% isopropyl alcohol and a lint-free cloth.
3. Use painter's tape to set the width of the silicone bead - not only will this make it look more consistent, but will also allow clean removal in case you apply a little too much.

HTH :)

[aravind90chan]

Thanks a lot @AquaticNerd for the thoughtful suggestions. Will keep you all posted on the progress.

[Tshethar]

+1 on Aquanerd's advice. I have done it with these steps as well. The Barkeeper's Friend is stronger than vinegar for hard water stains and not as dangerous to work with as muriatic acid, FWIW.

The blue painter's tape is what will give you clean lines when you're done, so it's highly recommended, but you'll want to pull the tape before any silicone starts curing on it or when you pull some may come up and you may lose your nice look. That happened to me in a couple of spots, but I was working on my porch on a 90+ degree day, and the heat I think meant that the curing was happening fast--before I could do all the seams. So, you may need to pull some tape as you go, though it may be better this time of year. But do give yourself adequate ventilation and make sure that the silicone will cure alright at low temperatures, depending on where you are and if you're working outside.

You can find some good Youtube videos that can also walk you through the process.

P.S. As with caulking, using your finger is a nice way to get a smooth finish, but you may want to put on a glove and have a paper towel handy to wipe on so as to keep the silicone from getting where you don't want it. The good news is that if you have any excess on glass somewhere, you can just wait until it cures and scrape it off with a razor.

[CraigJ]

Joey has a nice tutorial video if this helps; https://youtu.be/D_Meyb2JYCU

[aravind90chan]

Thanks a lot for the suggestions. So you guys would advice against any silicone forming tool? I saw custom aquarium folks using that in their videos.

[planter]

When I re sealed my tank I just used my finger to smooth out the caulk. I taped the off the tank to get nice straight lines. It worked like a charm It's as clean as the manufactures tanks which most of time is not perfect but "good enough" I suppose. Seeing that this tank is larger and will require a larger bead a forming tool might be a good idea. I've ever used one buy it looks pretty straight forward. It all depends on what kind of result you want to get. The tank I re sealed was already scratched all to hell so I really didn't care how it looked so long as it was leak proof which it is. You will have to work quickly these types of silicone's tend to form a skin on the surface quickly which makes it difficult to smooth out. Also if you don't like the smell of vinegar wear a mask and do this in a well ventilated area.

[Kirbs]

Did you get this done? How did it turn out?

I'm getting ready to try this out on my 90 Gallon. I ordered the Black Silicone aquarium safe from Amazon.

[Kirbs]

I should qualify.....The tube says "Safe for Fish" and "Forms a water-tight seal." The Brand is Aquascape Pro and made in St. Charles, IL.

[Mando]

3. Use painter's tape to set the width of the silicone bead - not only will this make it look more consistent, but will also allow clean removal in case you apply a little too much.

HTH :)


Make sure to remove the tape while it's wet!! do not wait. As soon as you lay the bead and pass your finger through it, remove the tape seconds after. I would not get fancy using any tools. Just the caulking gun, painter's tape, and your finger. Use a paper towel to clean your finger in between each swipe. I just did it with my skimmers and loved the finish product.

When the time comes to do my tank, I'll re-do it in black silicone.