Can a settlement chamber be too big?

[tstack22]

I'm finally going to get around to adding a settlement chamber to the pond that came with my house.

Is bigger better, or is there an upper limit?

My pond is about 3000 gallons. External pump rated at 6100 GPH, probably at about 3-4k GPH. Bio filter is rater at 4000 gallons. Little Laguna pressure flow filter (maybe 1-2k gallons) fed from 1" line on return, gets maybe 1/4 of the flow.

If I dig the settlement chamber to be 3000 gallons, or close to it, could it have a negative impact? Can it be too big?

[coolwon]

The bigger the settlement tank the absolute better.

The speed of the water passing though the settlement tank is all very important it must slow right down.

The dirt in the water it is carrying is allowed to slow down with the water,and drop to the bottom and be collected in the lowest point in

the tank.

Then flushed away by opening the drainage ball valve.

Minimal water loss, if it settles in the depression the ball valve is installed in.

[aquaholic]

There are several detailed threads on settlement chambers here if you search. The design is critical for efficient cleaning.
Even with very steep sloped bottoms, it's likely you will need to scrub or water jet the bottom clear periodically, so total drainage may be better. In which case several smaller chambers are better.

Why don't you build with the ability to drop in baffles in case. Changing flow direction and dropping water velocity will encourage settlement. (An increase in pipe or chamber diameter with same flow rate will reduce water velocity)

On my tank with 3 x 100mm bottom drains, I have purge valves and inline flow restrictor valves before filtration. The drain lines are about 8 meters long. On weekly rotation, I halve the flow rate on one drain which boosts the flow rate on the other two. At the end of week, I purge the reduced flow line which is jet black and full of the very fine particulates. Then rotate.

Essentially I'm using my bottom drains as settlement chambers.

[UnkleTim]

Our pond is 10,000 gallons and we have a 1200 gallon poly tank used as a settlement tank. Once a week water change from it.

[JMorris271]

I have a 5,000 gal. pond and use 2 250 gal. settling chambers. The longer the dwell time, the better it is to a degree. At some point, there will be diminishing return. Why do you want a 3,000 gal. chamber for a 3,000 pond?

[tstack22]

I have a 5,000 gal. pond and use 2 250 gal. settling chambers. The longer the dwell time, the better it is to a degree. At some point, there will be diminishing return. Why do you want a 3,000 gal. chamber for a 3,000 pond?

Basically because I can. When I measured the place I was going to build it, it was larger than I thought and turned out to be about 3k gallons. I probably won't do that big.

I'm considering getting a few old bath tubs and connecting those in series.

[tstack22]

There are several detailed threads on settlement chambers here if you search. The design is critical for efficient cleaning.
Even with very steep sloped bottoms, it's likely you will need to scrub or water jet the bottom clear periodically, so total drainage may be better. In which case several smaller chambers are better.

Why don't you build with the ability to drop in baffles in case. Changing flow direction and dropping water velocity will encourage settlement. (An increase in pipe or chamber diameter with same flow rate will reduce water velocity)

On my tank with 3 x 100mm bottom drains, I have purge valves and inline flow restrictor valves before filtration. The drain lines are about 8 meters long. On weekly rotation, I halve the flow rate on one drain which boosts the flow rate on the other two. At the end of week, I purge the reduced flow line which is jet black and full of the very fine particulates. Then rotate.

Essentially I'm using my bottom drains as settlement chambers.

Thanks for the info.

Any idea if using a few bathtubs in series would be effective? I assume I could find some for free and bury them in the ground, then not have to worry about pouring concrete and sealing it or getting a liner. I figure I could use a bulkhead fitting to connect them with 3 or 4" pipe, or maybe drill out the drain to that size and use it to connect them.

[hacnp]

On my system I use a 1500 Gallon round agricultural tank that is in the ground upside down. I have 2 4" drains feeding into it from my 10K pond. Flow rate is about 4500 GPH with a 1/3 hp Sequence primer pump. Gives me about 15 to 20 min. of dwell time and catches the majority of fines. Bigger is better IMO but 3K for a 3K pond is alot. Base it on flow rate and stocking rate, not pond size is how I would approach the issue. Best of luck!

[aquaholic]

I don't think bathtubs will give you much settlement capacity unless you fill them with brushes. Try to have easy individual purge ability whichever way you chose.

Getting settlement is half the challenge, having easy clean is just as important.

[gmessler]

I used a 500 gal tank on my 8500 gal pond. It was a bit small for the amount of flow I had going through it.
In order to help I used 90's just inside the tank on my feed lines so the water would swirl.
It helps because solids move to the center then. I brought the feeds in about 1/3 the way up and pulled the water from the side near the top.
I had a 4" drain at the bottom with a ball valve for clean out.


I liked the setup because I got a lot of drop out and it added 500gal to my water qty.
And when I cleaned out the tank it pretty much served as the bulk of my weekly water change.

What I didn't like was the muck still sitting in water, and the weekly (sometimes more) clean outs.
Also, I typically get a crazy amount of toads making their way through the bottom drains and skimmer.
They would make their way through the tank and end up in the pump baskets. If I didn't pull them out right away they would end up torn apart making a mess of the pond.

I recently changed to Zakki pre filters but use a small collection chamber before them to prevent sucking the pond dry if there is an issue.

Good luck with whatever route you decide to take.