bottom drain help

[cheeseburger]

ok so i am going to make a 4500 gallon koi pond which will have
a bog filter about 2 foot above it flowing down a waterfall into the pond
the bog filter will be 450 gallons is that good?
im going to have two bottom drains in my pond
my main questions are:

1: do bottom drains just suck the water up the pipe without the need of a pump?

2: would they be able to suck the water up 2 feet above the pond?

2: how big do the bottom drains and piping need to be?

3: do i need a pump?

 

[mrunlucky07]

1: do bottom drains just suck the water up the pipe without the need of a pump?

Unfortunately not. Normally they gravity flow to a settling tank or mechanical filter that is level with the pond. If you run one directly to a pump large debris could damage the pump, and everything gets chopped up and harder to filter out.

3" or 4" work depending on the area you are trying to sweep and how many GPH you are running through it. If you run two normally each one will have its own line to keep the flows balanced.

 

[cheeseburger]

so do i need a bottom drain or do sub pumps work just the same

if it would be better with bottom drains pleaase tell me how i can get the water from the pond up to the waterfall from a bottom drain

 

[cheeseburger]

can bottom drains get water above the bottom drain to another pool as long as it is below the water level of the pond

What I mean is if I have a pond with 2bottom drains and the bog is 2 feet above the pond and the bog is 4 foot deep so 2 feet of it are below the pond, can the boottom drains push the water up to the bottom of the bog which will be 2 feet below the pond

 

[cheeseburger]

Can bottom drains push water up above the bottom drain but not above the pond water level?

 

[mrunlucky07]

Water will flow from the bottom drain to another area and fill that area even with the pond level. So yes, If your bog is 4 feet deep the water in it will only be level with the main pond. You would then pump it back to the main pond for circulation. For drain size I hear you want around 2,000 GPH for a 3" BD, 4" requires about 2500gph. Less than that and debris will settle in the drain line.

Normally the BD flows to a settlement tank with a drain. That way you close the flow from the BD, drain the settlement tank, and when you reopen the BD water will surge through and clear the line.