Resealing a 150 gallon tank

[ReefsandGeeks]

I just found a great deal on a 150 gallon drilled tank, with a sump and alot of (dead) live rock that I couldn't pass up. I found out the reason the seller had the price listed so low was the tank has a minor leak at one of the bottom corners. He said he picked up a few tubes of aquarium silicon and was going to repair the leak, but I bought the tank as is so I could reseal the tank myself.

I'm glad I decided to reseal it myself because it appeared as though the seller was only going to scrape and reseal the corner that was leaking, not the whole tank. Of course that's no good since silicon won't stick to old silicone, so I am resealing the whole aquarium to make sure it is done right. I just got the tank yesterday and spend a good bit of time last night removing the old silicone on the rest of the inside of the tank.

I've got the bulk of the silicone removed, and will go over all seams several times with fresh razor blades to ensure all old silicone is removed and plan on wiping the glass at the seams with acetone to remove any residual silicone that the razors don't get.

although I was provided 2 tubes of marineland silicone, I decided to order Momentive RTV108 silicon and use that instead per my research online saying it is the best for resealing a tank. I will clean the tank out in the meantime and get it ready so once the caulking comes in I can get right on it. In the meantime, I plan on building a stand for the tank.

Any suggestions regarding sealing the tank, or building the stand are appreciated. This will be my first stand build, and my first time resealing a tank. I've read about building stands before, but not recently, so not sure what the best route would be. I'm planning on a 2X4 or 4X4 stand (or whatever size lumber is required)

 

[Vinny Kreyling]

Rocket engineers thread will have all the information you need with diagrams.
2x4 is plenty strong enough.

 

[mcgyvr]

You are removing the entire glass panel correct?
The main seal has failed and you shouldn't just redo the inner (non-structural) seal..

 

[ReefsandGeeks]

You are removing the entire glass panel correct?
The main seal has failed and you shouldn't just redo the inner (non-structural) seal..

I hadn't planned on removing the glass panel. looking at the silicone between the glass panels, still seems to be in good shape. No discoloration or bubbles that I can find. There must be some small imperfection I cant see or I guess even if the inner caulking leaked some, it still wouldn't get past the caulk between the panels unless there was some sort of leak path, right?

All of the videos and DIY instructions I found online just redid the inner sealing caulking, not removed panels and redid the structural caulking. Is it necessary to remove the panel? how can I tell?

 

[mcgyvr]

If a tank is leaking the main seal is compromised..
The inner seal is only there to protect the main seal from accidental damage,etc...
A tank should not leak even if it had no inner seal at all.. If it does it needs to be fixed by removing that panel.

150G of water will cause massive damage in a home..
The tank IMO is best left for a reptile cage now..

 

[davocean]

The only proper and certain way of sealing a tank is break down completely and reseal the right way, adding silicone on surface is just a band aid, it may or may not solve your issues, and if it does it's hard to say how long it will last.

 

[ReefsandGeeks]

Alright, Looks like I will need to remove that panel and reseal it. Not what i wanted to do, but better to do it right while the tank is empty. Thanks for the replies

 

[hellssephiroth]

You can't do only one panel. It will have to be all or none.

 

[ReefsandGeeks]

You can't do only one panel. It will have to be all or none.

That's inconvenient, but makes sense now that I'm thinking about it. I guess if i take a panel off, then the new silicone won't seal to the old at the corner and would leak. Well I'm really glad I haven't done this yet or I'd be in for an unplesent surprise. Thanks for saving me from that headache !

 

[pfan151]

It’s quite a job. Especially if you don’t know how to do it and don’t have the supplies needed. Make sure you have the spacers, clamps, and tape needed. And someone to help.

 

[ReefsandGeeks]

Thanks for the advice. I actually already did the resealing. with a new tank sitting there I cant help myself. I just have to keep working on it. I knew it was going to be a lot of work, but was much more intense than I thought. Super stressful with this size tank at least. I wish I had resealed a smaller more manageable tank in the past so I could have honed in on the step by step process to make things a bit smoother. Because of how fast you need to move with the silicone, there's really no room for mistakes so you and your help need to know exactly what to do and move fast with it before the silicone starts to set. I believe we did a good job, but things could have gone smoother. Either way, we ended up getting the tank put back together. I then did the "reseal" caulk job with the internal silicone seal and let it cure for a few days. I ended up using 4 tubes of silicone all in all, but tested the tank and it held water for 2 days without leaks, so I'm happy.

I would do it again if the right tank came up for a great deal and was worth the effort. But I'd purposely reseal a smaller tank just prior to doing the big tank with myself and anyone who would be helping me with the big tank so we could work out any kinks in our process before we attempt a large tank. Moving around big sheets of glass and lighting everything up is just too precise to not have a practice run first. Maybe consider the practice tank a sump or something if you're into making DIY sumps.