4300 Gallon Plywood Build (3600+ Take 2)

Pete,

What is your best guess as to where the leak is occuring? I wonder if you recreated the pressure on the walls that the water exerts on the tank before you recoated if this would make a differnce. I am envisioning something like load locks used in a semi trailor exerting outward force on the walls.

Is your floor made up of two layers of OSB over supports or just one?
 
Hello Pete...Just a thought that crossed my mind. Is it possible to somehow have a piece of plastic that you would temporarily put on the floor. (with tape or something) maybe going up the 4 walls for 5 to 10 inches. Put bricks around the edges where the walls meet the floor and evenly around the floor to keep the plastic/liner in place.
Then fill it and my thinking here is that the plastic and bricks might reduce the pressure enough to have it not start leaking when you fill it up until you fill up to say 40 or 50 inches.
That way you might identify a smaller area having the actual leak.
 
another question that I have is: Did Permadri comment or advise on this leak? You've talked to them many times, I know, but did you ever check with them again after the leak started showing?
 
The leak occurs between 27" to 30" depth.

I talked to my supplier today and he told me that I'd likely want closer to 80 mil thickness with the amount of pressure in the tank. Most Permadri applications are protection against moisture, not containing water. There are more and more applications like mine, but they are not the norm.

The coating does work for this type of application. Check the liquid rubber Canada site and see the application in the large marine aquarium. 96,000 gallons if I remember correctly.

I will fix the leak by applying more coating to the tank. The thickness I have on the tank right now isn't at 60 mils and it's holding very well other than this small leak. I went conservative on the coating because I wanted to have some left over for this very reason.
 
nc, no, I couldn't use anything like that. There's no way of seeing where the leak is at. The coating is black and over 3/4" plywood. If the source of the leak wasn't extremely small, the tank would be leaking like a sieve when I test fill it.
 
My guess is still the floor, but it''s just a guess. Seems like if it was occuring at the 27-30 inch range, a couple of recoats would have got the problem. I am thinking the water weight hits a certain point at that mark.....

If nothing else works, you might want to try to add more plywood to the floor with the seams staggered or better yet, criss-crossed from the first layer.

When you do get this thing filled, how long you going to let it sit before you feel confident enough to add fish?
 
Hey Pete keep up the great work, been following for a while now. Glad to see determination is winning over discouragement. They make a dye for a/c repair add it to the system and look for the leak with a black light. I wonder if there is something you can add to the water that would be safe and allow you to do the same. But then again you don't have complete access to everything anyhow =/. If I ever build something like this I will use this thread as a guide. Thanks! for the great info so far.
 
Knowing what I know about hydrostatic pressure, I doubt seriously that it's the floor. Especially, since I applied a thick brush coat to the floor after the first failure and the coating is the thickest on the floor.

No kind of detection system will work.

I don't have access to below the tank, the walls are pretty much 6 inch thick solid wood, and the water has to be channeling from where it's leaking to get where it's exiting from. There is a very slight slope to the room, so the water is following the path of least resistance down.

The tank is dry again. Ken wants to take a look at it. It'll most likely be when he's over tomorrow to help me install a new water heater for my house.
 
The leak is so small, pretty sure bet it's a hairline crack or imperfection somewhere in the coating due to stretching of some kind when pressure is applied by water.
Where? No saying for sure. Might be anywhere in the bottom or walls, or the joints where walls and bottom meet.
Only way to go would be to bring the thickness up with more coats and maybe leave it dry longer between and after applying the coats. Go with several coats after a really long drying period before you start and generous time for drying between coats.
Also, I would apply these coats both bottom, joints and walls, all of it so you take out any possibility for where the fault might be.

It takes a bit longer maybe, but the time it takes to empty and dry, plus the reduction in frustration right now will take as much time.

One more thought, not sure if it could make a difference...Pete, did you always apply the coatings in the same way? Meaning, did you always apply the coatings with vertical strokes on the walls for example? Or did you go horizontal, then next coat vertical, then horizontal again?

Might make it easier for hairline-faults to occur if you'd always apply in the same direction.
 
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