Backwash question

[Bdun111]

The intake for the external pump is the bottom drain.

 

[Meyer Jordan]

I was hoping that you would say that. Swapping the pumps would be your best option. Submersible to feed the waterfall and the external to feed the filter. Should be a definite improvement.
What is the gph of the external pump? It it is over 4000 then a simple ball valve inserted on the outflow side will allow this flow to be reduced/controlled.

 

[Bdun111]

Again, thanks for your help. So, by doing this it would I would no longer need a pre-filter? I am attaching a rough, very rough, sketch of the pond, with details showing pumps, drain, etc.

 

[Bdun111]

Couldn't open that file so lets try again.

 

[Bdun111]

The external pump for waterfall is a Pentair AF-120 with basket strainer, 120gpm(7200 gph)
The submersible pump is a Vancs/Tsurumi 50PN2.25s, 3630 GPH
The Pondmaster 4000 w/UV Pressurized filter, maximum pump capacity 4000gal/hr

 

[Meyer Jordan]

Thanks for the info. The pentair pump is,of course, too powerful for the filter, so the flow rate needs to be reduced to 4000 gph or less. At the same time I am sure that you still want the same flow over the waterfall and the submerged pump will not supply this. I still go with my original suggestion, but add a separate line with a ball valve split off the Pentair pump feeding the waterfall. This way you are optimizing your current available equipment. The leaf basket on the Pentair will serve as your prefilter (which it is anyway) and you will still maintain the desired flow to both the filter and the waterfall.

 

[Bdun111]

In the attached picture, on the left, it shows the pressurized filter, and the in-flow pipe, along with a Jandy 2-way valve. This valve is always in the full open position. Would I be able to install some type of pre-filter around this pipe area, On the right is the Pentair pump, which if I did use with filter, I could control flow with the Jandy valve?

 

[Bdun111]

There is a screen filter in the pressurized filter, #23 in picture.

 

[Meyer Jordan]

There is a screen filter in the pressurized filter, #23 in picture.View attachment 101482

Yes, and it states in the manual that this is a media screen and should never require cleaning.

Would I be able to install some type of pre-filter around this pipe area

As was mentioned earlier any pre-filter must be on the intake side of the pump otherwise the pump will just grind up larger pieces of organic debris into pieces too small for a pre-filter to trap.which would then clog the biofilter.

 

[Bdun111]

The screen inside the filter was what was causing the pressure to be so high, because it was clogged. But, since the sub pump that feeds it has inlet holes about an inch squared, photo attached, maybe that's the problem. The pump lays on its side

 

[Meyer Jordan]

The screen inside the filter was what was causing the pressure to be so high, because it was clogged. But, since the sub pump that feeds it has inlet holes about an inch squared, photo attached, maybe that's the problem. The pump lays on its sideView attachment 101485

That is known as a solids-handling pump/ Fairly large debris will not clog it. It just chews it up. This is why your filter is clogging/ These types of pumps are typically utilized in a skimmer in a pond application.

 

[Bdun111]

I am amazed at what I have learned about since trying to figure out what was causing the water to be dirty, with my mom's pond waterfall.
I understand that the company that installed it may or may not have known its intention to be used as a koi pond, but really, it looks like they didn't know anything about filtration. The construction of the pond itself is very nice, but everything else was terribly planned.
I have a smaller pond, with a waterfall, which has a fountain attached to a pump, down inside a diy filter i made and the water stays crystal clear year-round.