Re silicone used tank

benapilot · Sep 7, 2015

I bought a used 75 gallon aquarium from my LFS. The silicone on the corner edges was pretty thrashed so I'm planning on redoing it. The bead around the bottom looks real good and the top is decent enough. The silicone between the panes looks real good, too.

I just want some affirmation that just redoing the corner runs with new silicone is ok.

This is with the corner bead scraped out:

twilliard · Sep 7, 2015

Here is my saying..
If 1 part needs repair do it all

Its so easy to seal glass tanks
And as your doing it you can see the seal you are making.
Cut all the old silicon out and put your new beads in.

benapilot · Sep 8, 2015

I was afraid I'd get that answer!

LOL!

Better to take the time now instead of wishing I did after it's set up, eh?

mikey_p · Sep 11, 2015

i had gotten my 220 from a buddy a while back thought the seals between the glass looked good so went and scraped just the inside and resealed it and then filled up and busted the whole bottom out...id say split them all and reseal it completely alot safer that way now whenever i get a tank from anyone i split all the glass and rebuild them

pelphrey · Sep 11, 2015

I bought a used 90 and had to reseal it. I did the same thing as mikey_p, resealed the inside and it leaked (mine didn't bust). I had to then scrape it all out again and take it apart. Long story short I didn't do so well rebuilding the tank and ended up having to take it completely apart a 2nd time. After that I sold it for pennies since I had already spent way too many hours work on it. Resealing tanks just isn't for me!

Harold Green · Sep 11, 2015

I definitely wouldn't partially reseal a tank. On smaller tanks I've removed only the inner filet of silicon and gotten a good reseal but I also cleaned the inside thoroughly with alcohol before resealing. If you get a good enough price on a used tank then I'd totally reseal anything large enough to have a problem in the future.

benapilot · Sep 11, 2015

Ok.... Now I'm nervous. Not sure I want to take the whole thing apart.

It's got 1/2" glass which is thick for a 75 and the silicone looks good between the panes. If I reseal just the insides and it holds, could I call it safe? Is there a chance that years down the line it could give way??

mikey_p · Sep 11, 2015

I'm sure there's always a chance of that no matter what you do if ur nervous ab splitting it then maybe just reseal inside and let sit for a few weeks filled under pressure and go from there or have someone split it and rebuild for you

mikey_p · Sep 11, 2015

I do kno that whenever I split a tank and reseal I leave filled to rim with water and alot of rock to make sure it can hold the pressure of it all

Harold Green · Sep 11, 2015

I'm sure there are plenty of us out there who have had a new tank leak or break. Sometimes the factory just doesn't do as good a job as we expect. Last year I bought a 210g tank and when I uncrated it there was a four inch chunk of glass broken off one edge. I know it happened at the factory because they polished the glass after the break. The factory rep took one look at it and replaced the tank. What I'm trying to say is there are no guarantees that a tank won't leak or break. Did you try to fill the tank before removing any silicone? Did you cut the old silicone out with a razor blade using the proper technique? Saying you scraped the seal out doesn't sound good. The point is if you didn't damage the silicone between the glass and it didn't leak then you have a chance it will hold by doing a good job on resealing the interior. I'd reseal it and use it as a frag tank or something and just purchase a new tank if you're always going to be leery of it. I'm sure there are some good videos on how to cut the silicone out from between the tank glass and it might be well worth the trouble if you're patient on rebuilding. The old glass has to be thoroughly cleaned before redoing. Good luck.

benapilot · Sep 11, 2015

I didn't fill the tank before removing the silicone. The interior silicone was discolored and since the tank was manufactured in 1992, I thought maybe I'd redo it for aesthetic purposes. On the seams that I can see, the silicone between the panes look great, no bubbles or gaps. I watched a Couple YouTube videos on redoing the silicone and was careful not to disturb the silicone between the panes. I used a razor blade....

Am I correct in thinking the new silicone will bond with carefully cleaned glass? What about the existing silicone between the panes?

pelphrey · Sep 11, 2015

Like mikey said I'd reseal the interior of the tank first and water test it. That is what I did on the 90 I bought and 4 days later my garage was full of water. Trust me, it is much easier to scrape all of the silicone off the interior of the glass VS taking all 5 pieces and scraping the glass for a few days. I'll go ahead and give you a hint. Get a box of at least 100 razor blades and a good razor blade holder, a bottle of acetone and a roll of paper towels. If you do have to remove all of the panels you can get a new trim pieces for $18 a piece plus shipping ( http://www.glasscages.com/?sAction=ViewCat&lCatID=43) and they are black. I have no experience reusing trim but I see no issue with it as long as you don't crack it. Just like taking the tank apart slow and easy. Be patient as you know when you will be able to lift it off, if you pull on it they can and will break.

I also prefer ASI Aquarium silicone. Putting a tank that size back together is for sure a 2 person job. Unfortunately for me the youtube videos made it look easy. Don't let that scare you. It's all a learning curve and no better way to learn than to do it. If you can reseal that tank successfully you are set to pickup an even bigger tank down the road that may need resealed and get it for next to nothing.

Harold Green · Sep 11, 2015

I doubt the silicone will adhere to the existing silicone but since you're only talking about a knife blades thickness it really shouldn't matter. Clean the inside(I use just plain alcohol) thoroughly then run a healthy bead of silicone. Most of the new tanks have a pretty wide filet on them. Especially on thicker glass. Work quickly so each bead will adhere to the next before they skin over. A damp finger makes a pretty good tool to smooth the silicone. I would allow twice what the silicone suggests and wait at least two days before filling the tank to allow for better curing.

benapilot · Sep 11, 2015

Ok. Thanks guys!!

I'll clean the interior real good then reseal. After I get my stand built I'll put water in it and wait a while.

ReeferBob · Sep 11, 2015

I think you are going to find that you regret this project. If it was me, I'd get a new tank. Sealing a tank isn't an easy job. A new 75 is cheap.

pelphrey · Sep 11, 2015

Use tape when reapplying silicone also. This makes for a smoother finish.

mikey_p · Sep 11, 2015

if your gonna just reseal the inside then fill it up outside on level ground and leave it for a few weeks maybe even put some rocks in it to add weight and pressure to it

don_chuwish · Sep 14, 2015

Curious to see how this turns out!

benapilot · Feb 19, 2016

For those that may have been following along... I resiliconed the inside, built my stand, and it's been in the garage full of water for a couple weeks with NO leaks! I've still got a long way to go before I'm ready to go live (building the skin of my stand, finishing up the sump, then I'll tear down my current 46 and redo the floors and baseboard in the room). Until then, I'll keep water in with the pump running. So far so good!!

You can check my build thread here: https://www.reef2reef.com/threads/benapilots-75-gallon-build.231738/#post-2696255