4300 Gallon Plywood Build (3600+ Take 2)

Easier to just empty, dry out, coat the bottom/reinforce seams then let cure then test fill again. There's no applying pressure to the bottom to see if it changes flow.

Working on draining rest of water below the bulkheads out now.

Hello Pete, too bad, but only a small leak. Keep it going.

For draining the rest out, I'd take out the cap of a bottom drain, stick a 1 inch hose through, make sure it stays at the bottom (maybe with 2 stones taped to it) and syphon it out.
 
I dont think siphoning it out would work since the bottom of the tank is level with thr floor right? siphons need gravity to work.
 
I dont think siphoning it out would work since the bottom of the tank is level with thr floor right? siphons need gravity to work.

Understand your point, but for 2 things:
1. Pete's tank-bottom is at least 4" or so above the concrete slab since he has put in a wood construction bottom similar to the sides of the tank.

2. If he uses a long enough hose (say 20 - 30 feet or so) then the pulling of the water in the hose (similar the syphon) would be enough to overcome the lack of height-difference anyway. That syphon works to certain extend horizontal as well.
 
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