Need help with a spillway idea

[qclabrat]

I have a 100G holding tank bog which I am using to supply a waterfall. The inlet is a 2" PVC and two 1.5" PVC outlets to supply the waterfall. Unfortunately it's not enough to drain out the water and the water overflows. Instead of just drilling more holes. I figured to ask here instead. Should just put in a regular spillway? I didn't go that route because I couldn't figure out how to prevent leaking, so went with the PVC outlet instead. I was considering to add one 3" PVC to start, but the size is pretty tight. I'll post some pictures when I get home.

 

[Panzer13]

Sounds like the spillway or the pipe would work. I use copper pipe. I like the look and if you use pipe you can control the fall of the water more. It also allows you to control the noise of the water by adjusting how far the water falls.
I do like the look of a spillway though, more like a waterfall.
For me the trick is just sealant and lots of it. I use a gutter sealant, it dries purity fast as it's tough.

 

[sissy]

so the tank is filled with gravel .If you have gravel in it could there be to much gravel and not enough space for the water .I(f plants are in there the roots could be overgrown also .

 

[carolinaguy]

if you can fit a spillway, great. it is the most flexible. you might look into using sikaflex as the sealant. it can be ordered on line or at a local distributor. i think that is the name of the product. check on a google search. pretty powerful stuff. lexcel might work too if the joint is stable. its available at ace hardware. its great for gluing two liners together. i used it to seal our bottom drains, and it worked perfectly with a 51 inch water depth. no pressure leaks. any time you use a gravity return from a pool that is fed by a pump, the output has to be at least 3 or 4 times the input pipe diameter. you can also valve the input and adjust the flow to match inputs and outputs. there is also the dynamic of determining the thickness of the water sheet coming out to maximize oxygen exchange. our outflows are maybe a quarter inch deep and provide excellent oxygen exchange.

 

[qclabrat]

Here's my setup

 

[sissy]

Did you leave space at the bottom of the tank for water .You almost have to treat that as like a pondless feature .I use these soda bottle holders as a space to the bottom

 

[qclabrat]

Did you leave space at the bottom of the tank for water .You almost have to treat that as like a pondless feature .I use these soda bottle holders as a space to the bottom View attachment 113689

I didn't, there's a downward slitted 2 inch PVC along the bottom and the water draws upward

 

[sissy]

gravel then water add up to way to much .If you look at most bogs there is standing water that flows back into the pond .Yours goes through an outlet .I use the soda holders to leave space for water to flow out

 

[Lisak1]

I would definitely convert to a spillway. The outlets are set high in your design which I would assume makes it just as easy for the water to flow over as to spill out through the outlets.

 

[sissy]

once the roots grow it will get worse