The trouble with water is that it likes the lowest point it can find. In my case, it’s the carpeted floor.
I am struggling with the overflow box.
I found a small pin hole in the top part of the siphon. This only showed when the hole was dry. I guess when it was wet, water couldn’t be pulled through, but dry, air can get through. Some silicone fixed that easy enough.
With that, I got the water flowing again through the siphon.
About 10-15 minutes later, the tank overflows. It looks like with my new, longer tubing routed the way it is along the back of the big tank, air bubbles form and block water flow.
This caused the tank to overflow. Again.
I will try routing the tubes to go into the tank more directly. With no horizontal tubing, the air bubbles should not form.
If THAT doesn’t work, i will find bigger tubing and outlet ports. It’s drilled for a size larger tubing with a reduced outlet port.
If that doesn’t work, I will drill the ports directly into the side of the tank. I will probably take the glass end-cap off and put in acrylic so I can drill it more easily.