Water Replacement (for Irrigation)

[Wildneg]

So I'm not sure if I mentioned this before, but I built my pond originally to hold rain water so I could irrigate my lawn. I wouldn't irrigate all the time like some other folks do. I plan on irrigating when/if I overseed that fall, when I fertilize the lawn and apply certain herbicides. I would probably also irrigate every few days for a little bit during drought/high heat to just keep the grass from completely browning.

I put in a pond (roughly 11K gallons) and have added fish. I've trenched all my piping to the bog filter, waterfall and also the inlet to the irrigation pump. I also have a bypass setup so I can prefill the irrigation lines across the yard from my house's well pump. I can then turn on that 'zone' to fill the pond up. Trying to work smarter, not harder!

So with all that being said, I setup the irrigation pump this past weekend and all works well.

My question comes down to water cycling. I have overseeded about an acre on the side of my property this year. I didn't have time (or energy) to do the back, front and other side. With that, it takes frequent short watering's to get the seeds to germinate (not my first rodeo here). After the next 4 or 5 days, I'll go to watering just once and eventually every other day.

The problem right now is we have had almost no rain and not a whole lot in the forecast. When it does rain, that pond fills up pretty quick. I have my entire house/garage roof going down into 4" piping which feeds the pond. Even a little rain goes a long way. So I will be refilling the pond with well water during the middle of the night (when needed).

I have not done the raw math, but I would say maybe every 2 days or so, I may be using about 10% the pond water and replacing with well water. Would this hurt the chemistry of the pond? I'm doing NO scrubbing of rock or other features in the pond. So the bacteria should really remain unimpacted. My only concern was taking out too much nutrients that the plants need (from the fish) but I have some algae growth as it is. This could be too much nutrients or the simple fact that the pond is probably still going through the entire cycle (about 60 days old).

By doing this 10% (maybe even 20% every few days) swap of water, how concerned should I be? What should I look for? I have a testing kit and I do test. I've swapped about 10% of the water as of this past Saturday and so far, the fish are as happy as ever. So are the plants in the bog. In fact, I cleaned out the piping in the bog filter earlier today and everyone was eating anything that came back into the pond. Probably baby fish... haha.

I want to use my pond for irrigation like I plan but I also want to manage the water the best way possible, keeping the ecosystem in that pond healthy. I feel since it is well water, I have a lot less I'm fighting by simply replacing the water that I use for irrigation (no chlorine). I only do this because I can utilize saved rain water and my house well pump isn't strong enough to be running 3 sprinkler heads per zone.

As always, appreciate any feedback!

 

[Wildneg]

I will also add, been watching water temp too. It's just been the normal swings fr night to day. When filling back up, bo noticeable change with my thermometer.

 

[JRS]

I think you will be fine. The fish will appreciate the freshwater. Lots of fish wholesalers used a constant trickle water change system to flush their tanks and keep the water as clean as possible. Your 10% gradual water change should not be an issue at all.

 

[Mgessert]

I agree, as I use my pond to water my veggies, and usually add about 10-20% by volume per week, either rain water or municipal. I’ve been doing this for five years with no issues.

 

[poconojoe]

I never do water changes, but on another note:
You seem to be feeding the irrigation with both pond water and the home's well water.
You may already have done this, but thought I'd mention it just to be sure.
I would be sure to have an anti-siphon check valve in the line from your well. You don't want anything from the ground leaching back to your home's water supply.

 

[Wildneg]

I never do water changes, but on another note:
You seem to be feeding the irrigation with both pond water and the home's well water.
You may already have done this, but thought I'd mention it just to be sure.
I would be sure to have an anti-siphon check valve in the line from your well. You don't want anything from the ground leaching back to your home's water supply.

Yes. I actually have a irrigation valve to control (to control when to fill) and an the anti siphon. I also have the shut off to the irrigation line when needed.

My irrigation main line is fed from house well originally. Now I feed it with the irrigation pump from pond. All controlled with irrigation zone valves. So technically, I can run irrigation pump from pond, back to pond or from well in house.

I thought all this out months ago so I didn't have to put any new lines in. But still ended up missing a low voltage line.... Just when you think you thought of everything needed, you miss something!

Thanks for the heads up though! I almost forgot to put one in. My dad ended up reminded me.

 

[Jhn]

Agree with everyone, in effect doing 10% water changes every few days will minimally impact your ponds water quality.