Settlement Chamber Leak and Advice for Replacing

[Emily Mc]

Hello all...I have not been on this site for a few years since all was well with the pond until the past 2 years. The issues do align with when I found a mole in the pump basket and could not figure out how it got in there.

As the picture shows:

I have 1,200 gallon formal Koi pond with 3-4 foot depth built in 2016. Walls are concrete blocks and EPDM liner.
In the past 2 years a leak has gotten worse. In the last month it is now leaking large amounts when the pump is on (4 inches overnight) and small amount (½ inch overnight) when the pump is off.
Plumbing up to the waterfall was redone last year and the pond is still leaking.
Last month we discovered there is water in the neighbor's yard in the ground next to where the settlement chamber is buried. So now I turn the pump off at night.
Leak could be in any of the red outlined area in the pic.

Before we move the koi and tear it apart and start fixing it, I wanted some confirmation that a gravity fed settlement chamber leak would be much worse when the pump is on.

Should we replace the settlement chamber with a sieve type of chamber? It is hard to clean the current settlement chamber and it is visibly warping.

Thanks!

[coolwon]

Water leaving the water pump is at a much HIGHER pressure.

The return water,with a leak from the settlement tank, would draw air, and have bubbles entering the pond.

Therefore, one would assume the leak is between the water pump and the pipe returning water to the pond.

Some types of plastic joints and elbows breakdown with time.

I found the red ones as opposed to black ones were short lived.

Worth looking at before you go lashing out big money.

[Emily Mc]

Thank you, we have been searching for this leak for 2 years now but now it is much worse and the neighbors are complaining and I only run the pond a few hours a day. We rerouted the waterfall last year and still saw a leak but yesterday I pulled 10 lbs of roots from the waterfall. I still think there are two leaks and one in the settlement chamber since it is warped at the top. It was never really a solid thing to put in the ground like that and its so hard to clean. Want to replace it all with easier things but don't want to do an aquascape type of pond (been there). Local pond maintenance people are saying to use a bead filter instead? The HydroSieve Compact Sieve Bottom Drain & Pondless Waterfall Pre-filter looks like it is easier that a drum settlement chamber.

[Myrlin]

Hi Emily,

If you have reason to think Coolwon is off the mark. (His advice definitely would warrant a second look at the return piping and pump)

I'd try to isolate the leak by blocking the output from the bottom drain pipe to the settlement chamber.

Maybe:
-Install a cap or perhaps a ball valve in the settlement chamber input line? Close it off, and see if the pond still goes down. You may be able to get a water tight seal on the ball valve (or perhaps a cap/plug) with teflon tape, so could install it with water in place?

I'd guess the leak is in the pipe, as the pressure in the chamber (if open to the air at the top) would not change all that much with the pump on.

good luck.

[Emily Mc]

Thank you! We do have a valve that blocks the bottom drain but it is broken and doesn't shut all the way (another reason I think we should start over) but yes I am going to try all suggestions. Very helpful thanks.