Bottom drain question

[Bdun111]

Hello. My older mother has a 3-tier, 3000 gal (rough estimate ), Koi Pond with Waterfall, that I am trying to help find out why the pressurized filter system doesn't work correctly.

It seems to me that there is some sort of bottom drain that clogs, which slows down the waterfall.

I will attach pictures and list what equipment is installed and how it is setup then post my question.

This is a rock bottom, 3 level pond with waterfall. Currently there are approximately (20) Koi, up to 15", and plenty of submerged plants.

Submersible pump in lower level of pond
Extrenal Pond master pressurized filter with UV light.
External 120gph pump with basket filter.

The submersible pump circulates water 24/7, but after turning on waterfall system for 15 minutes, the flow rate slows and then stops completely, until resetting electrical.
The filter is maintained as directed.

I found what feels like the attached picture of a bottom drain in middle of the pond, and at the time it was covered in rocks (2-3 diameter rocks and 2 deep all round grate), and when I cleared the rocks and debris the waterfall started really flowing. However, after about twenty minutes it slowed again until will cleaned out the external pump filter basket.

Basically, does this sound like the right setup but something we do is causing the problem? Is there normally just one of these drain? Should there be a skimmer somewhere?
If so I said too much , I apologize. If there is something I missed , let me know.

Ty

 

[Dave 54]

Nice Pond @Bdun111 the bottom drain we have on our pond is the right hand darker coloured model which should be routed via a large filter .
The valve sticking out about part way down it would be connected up to a bubbler via way of a large koi airpump and sshould be lefr in 24/7 365 days a year the action of the bubbler causing the detritus in the pond to be removed via the bottom drain direct to a filter via a vortex filter [well that is how ours is set up works ...
Could you please tell us when this pond was last given a major clean out by use of a pond vac please ?

Dave

 

[Bdun111]

Thanks for your reply. The pond has never been cleaned as you described. I don't think I have seen "bubbler", unless it is disconnected and submerged making it unseen. The submersible pump in the bottom area of pond feeds into wall via pvc. There is a jet of return
Water on opposite wall and these two are on 24/7. I don't know if it is related but there is a 1/2-3/4 pvc pipe coming up out of ground in a straight line between lower pond and external filter/pump up by waterfall, which is uncapped. The company that installed it had subcontractor do plumbing and do not have any plans.

 

[Meyer Jordan]

Seems doubtful that you would have a bottom drain and a submersible pump.
There is an external pump (certainly larger than 120gph) plainly evident in the photo. Is this also being used?

 

[Bdun111]

There is a large submersible "sump" pump, in the pond that is about 1.5ft in length. The suction area of it is about 4-5". The outlet is connected to a flexible tube which inserts into the concrete side wall 2-3" pvc inlet.

I don't know if it just used for circulation back through 1/2" outlet on opposite side, because once before a valve was turned off at pressurized pump inlet and this caused flex tube to disconnect from pvc inlet. The return Water also stopped.

As far as the bottom drain. The picture I attached (White) is the closest thing I found that looks like what I can only feel with my hands. I have not actually seen water is under the water.

Under two to three latest of rocks is a square concrete piece approximately 18x18 or less. The cover to some sort of suction device is in the of this. When I first discovered this and moved rocks and debris from around grated area of plastic type lid, the waterfall system immediately started working at full force. However, it slowed within a few minutes due to the basket filter part of the EXTERNAL pump was clogged. After turning off waterfall and cleaning the basket it ran full force again.

Currently the rocks are pushed away from this area but debris accumulates quickly.

Should this be covered with rocks?

I also mentioned to my Mom your comment about bubbles and she has seen them from time to time. She thought it was from sub pump pipe that come loose.


The circulation water and sub pump are always on. However to run the waterfall there is a light switch that turns it on. When turned on the water action of the external pump starts circulation through basket filter.

 

[Bdun111]

Seems doubtful that you would have a bottom drain and a submersible pump.
There is an external pump (certainly larger than 120gph) plainly evident in the photo. Is this also being used?

 

[Bdun111]

Yes, I tried to explain how both, what i assume or being used as pumps, are currently being used. The setup does not make sense to me, which is why I got involved.
The external pump only engages (meaning actual water is seen circulating in clear basket chamber), when a switch to turn on waterfall is turned on.

 

[Meyer Jordan]

Yes, I tried to explain how both, what i assume or being used as pumps, are currently being used. The setup does not make sense to me, which is why I got involved.
The external pump only engages (meaning actual water is seen circulating in clear basket chamber), when a switch to turn on waterfall is turned on.

Then it appears that the waterfall and the biofilter are plumbed separately. Does this seem correct?
As to maintaining flow without constant clogging. a good cleaning of the pond to remove all accumulated debris would be the indicated first line of action.

 

[Bdun111]

Would it be possible that the submersible pump is only used for circulating water through the pressurized UV filter and back to pond, and external is only used with bottom drain and UV filter?

 

[Bdun111]

Lol. I think we are figuring it the same way.

 

[Bdun111]

In the picture I am attaching is a valve shut off. It is in open position and runs to UV filter. Once before it was turned off, the pressurized filter expanded, and the flex tube for submersible pump was forced off pvc inlet and sprayed water everywhere.

 

[Meyer Jordan]

Once before it was turned off, the pressurized filter expanded, and the flex tube for submersible pump was forced off pvc inlet and sprayed water everywhere.

This indicates that the pump has a flow rate larger than the filter can handle. Diverting some of the UV corrects this problem, but you may have too much flow to the UV for it to be effective.