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Old 03-02-2003, 09:30 PM
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Default Settlement Tanks

I disagree that we need additional filtering, John.
Let the veggie filter do its work. If you must,
place a screen in the veggie filter.


"John Hines" wrote in message
"BenignVanilla" wrote:

"John Hines" wrote in message
.. .
"BenignVanilla" wrote:

Is there a sizing algorithm for settlement tanks?

Sure, keep the water in the tank long enough for stuff to settle!

*laugh* OK, so what's that time period?

It isn't hard, get a clear glass tumbler out of the kitchen, fill it
with pond water, shake up, and see how long it takes for the stuff to
settle out to the bottom.

To sum it up, it takes a while, so the settling rate is how much (%)
settles out per minute.

If you connect a 30 gpm (1800gph) pump, that would allow less than 10
seconds settling time, which is to say none.


I did some quick math, assuming a 2000 gallon pond, and an 1800GPH pump.

would take the pump 67 minutes to circulate the water in the pond. With a
200 gallon settlement tank, the water would have only 7 minutes to settle

the tank. I realize this does not take into consideration of the volume

the pipes. I am just trying to get close here. So is 7 minutes enough? I

guessing not. A 500 gallon settlement tank would provide about 17 minutes

settle time. Still seems a bit low.

That will work. Try my test in the first point., a few minutes will
allow a great percentage of stuff to settle out.

The idea of the settlement tank is to get the big stuff out.

The reason I ask is that, it seems like a lot of work and doing to get a
settlement tank going. Since I plan to have a shallow veggie filter,
cleaning it should not be a big deal. I am wondering if I should just

the settlement tank, and let the sediment come into the veggie filter,

could easily be drained, cleaned and refilled.

Filtering needs to be done in stages,
first you screen out the fish,
then the largest items,
then the smaller items,
and so on.

A settling tank is for the larger, coarser, heavier items, a prefilter
to a finer filter, like the veggie filter.