Cleaned pump, now it is working too well?

[HelpTheNewGuy]

Hello and thanks in advance for any help. I love that enthusiast forms like this exist and am glad to have found this place!

I recently purchased a new home which includes a two-level garden pond with a stream/waterfall connecting the two levels.

Upper pool-

Lower Pool-

I didn't receive much/any instruction from the prior owners but they did say that occasionally they just picked some of the algae out of the mesh filter bag around the pump if the flow between the two pools stopped.

I felt like it wasn't getting super clean so yesterday I removed the pump from the crock/basin at the far end of the deeper/lower pond and washed out the bag and cleaned the pump. Mostly just scrubbed it down, removed the magnetic impeller, hosed it off, etc.

When I put the pump back in, it seems to be working too well? The pump is emptying the crock faster than the waterfall can refill it and after an hour or so of being on, the pump starts sucking air. I am a bit confused about what may have changed and what I can do to fix this. Do I need some sort of regulator/ball valve?

Catch basin that is emptying out before it can be re-filled-

My initial thought was that the pond was just low on water, but both pools seem quite full and above any prior water line I can see?

Any advice would be greatly appreciated! We also put 2 shubunkins and one fin-tail gold fish a week or so ago into the bottom pool. If anyone sees any other obvious issues or challenges we should address for their success, I would love any advice.

Thanks!

 

[WaterGardener]

Is there a chance that the pipe feeding the pump could be clogged?

 

[Mmathis]

Hello and welcome! Maybe what @WaterGardener said?

 

[JRS]

Welcome! Nice spot you have there.

If the intake is clear, it seems they may have undersized the catch basin for the pump size at max flow which happens when clean. You could put a T fitting on the output side with a valve on the side to allow some of the water to recirculate into the catch basin. This will slow the flow to the pond and keep the water from emptying too fast.

Another option would be to increase the size of the basin or the inflow area. Is it some type of surface skimmer?

 

[HelpTheNewGuy]

Is there a chance that the pipe feeding the pump could be clogged?

I don't believe so. There isn't actually a pipe feeding the pump down on the pump end. At the upper pond where the pump dumps water, it certainly seems to be flowing out plenty fast, so I don't think that is closed.

At the bottom, water flows from the bottom pond over this sort of accordion-like door thing and into the basin and the pump is just sitting loose in that basin.

 

[HelpTheNewGuy]

Welcome! Nice spot you have there.

If the intake is clear, it seems they may have undersized the catch basin for the pump size at max flow which happens when clean. You could put a T fitting on the output side with a valve on the side to allow some of the water to recirculate into the catch basin. This will slow the flow to the pond and keep the water from emptying too fast.

Another option would be to increase the size of the basin or the inflow area. Is it some type of surface skimmer?

Thank you, I am very excited. Some minor maintenance and cleanup I know I need to tackle but it Is a beautiful feature.

By a t fitting, do you mean something like THIS inline with where the pipe is running up to and then turning it to be partially closed to restrict the flow up to the upper pool? I had thought about that.

Another idea I had was hooking up some sort of variable speed dial (like for a router) and trying to turn down the pump that way. But I don't know if that would work if the pump is not explicitly designed as a variable speed pump?


And sorry, not quite sure I follow your question about a surface skimmer. Both the lower pond and the basin are kind of molded into the ground/attached to one another. Not sure if expanding either would be an option. Getting a smaller pump would probably be easier/cheaper if the pump being oversized ends up being the issue.


One thing that does have me scratching my head is that looking at the pump, it is a 5100 gph model from 2017. So clearly it hasn't been running dry frequently for 5 years since that surely would have killed the pump. So this setup has been working for several years before I monkeyed with it...

 

[HelpTheNewGuy]

Welcome! Nice spot you have there.

If the intake is clear, it seems they may have undersized the catch basin for the pump size at max flow which happens when clean. You could put a T fitting on the output side with a valve on the side to allow some of the water to recirculate into the catch basin. This will slow the flow to the pond and keep the water from emptying too fast.

Another option would be to increase the size of the basin or the inflow area. Is it some type of surface skimmer?

Just realized you may have meant instead of a valve that I should put in what would basically be a second small waterfall so that some of the water never gets all the way to the upper pool.

So basically adding a t where the start of the red arrow is and a pipe to allow some water to exit where the head of the arrow is. Interesting...

 

[j.w]

@HelpTheNewGuy
I don't have a catch/basin so can't help ya there.

 

[JRS]

Just realized you may have meant instead of a valve that I should put in what would basically be a second small waterfall so that some of the water never gets all the way to the upper pool.

Not necessarily. If your pump was not in the catch basin would it run dry? As far as I can tell from the picture, it looks like water is flowing into the catch basin through a hole in the side. I think your pump is pumping it out of the basin faster than it can flow in. If so, you need to restrict the pump flow with a valve to slow it down or put more water in the basin by diversion directly into the basin with a T and valve, which is what I was describing.

What you are describing would be the case if the level of the lower pool was below the catch basin entry point and/or below the pump intake if no catch basin.

 

[HelpTheNewGuy]

Not necessarily. If your pump was not in the catch basin would it run dry? As far as I can tell from the picture, it looks like water is flowing into the catch basin through a hole in the side. I think your pump is pumping it out of the basin faster than it can flow in. If so, you need to restrict the pump flow with a valve to slow it down or put more water in the basin by diversion directly into the basin with a T and valve, which is what I was describing.

What you are describing would be the case if the level of the lower pool was below the catch basin entry point and/or below the pump intake if no catch basin.

Ah I see what you are saying now.

I had another post that the auto-mod flagged because it had a link out to a valve which I think just got approved. That is a good thought and may be what I try next.

 

[Laaf]

Did you solve your problem? I was wondering if the water level simply got too low and you just need to fill it more.

 

[secuono]

A bigger hole in the basin will fix that. Or a smaller, weaker pump.

 

[HelpTheNewGuy]

Providing an update for anyone that may encounter this in the future. Installing a ball valve seems to have largely fixed the issue.

When the pond is full and the ball valve is ~70% closed the system seems to run more or less in equilibrium and the basin no longer empties nearly as fast. Very curious that it takes the pump being that heavily restricted given that the pump has been in use for 5+ years in this system.



I ended up going on a bit of a side quest as the back pressure from the new valve exposed a small pinhole leak in the flex PVC that the pump is using to carry the water up to the upper pool.

I think I fixed that leak but I did lose around 3 inches of water yesterday even after the fix. It has been 100+ degrees here the past few days though and the stream element is fairly long/shallow so not sure if that may be largely evaporation.