135,000 gallon Koi/Fish pond, advice on water quality/filtering etc.

[Foreverunstopable]

Hi folks.

Where to start. We moved into a new home about a year ago with a 135,000 gallon pond as best I can calculate.

1/8 acre 5,500sqft 4-5 Ave depth
100ft x 60ft oval
135,000 gallons
Well / rain fed on a slope.
Liner
Fountain
Skimmer
2 airators, the membrane pump type
Waterfall
Not to much natural shade until late in the day.

The prior owner said it was about 8ft at the center, haven’t tested that out yet.

There are a mix of fish in the pond.

Koi, about 12-20? About 18-24in long, the water is murky and I never see them all when we feed.

A few Bass, only caught one big female and a smaller male.

Quite a few Bream, small and large.

A few “Placo” not sure..

And at least one decent Katfish.

When we bought the house there was a leak in the liner which we located and had repaired. At the same time as the repair they added an active skimmer to a waterfall on the opposite side which runs 24/7 filters most of the floating stuff into a basket with a sponge type filter we clean weekly. Also added some plants which the Koi have mostly eaten/destroyed lol…

Our water is pretty murkey, seems to be a mix of light algae and the fish stirring up the bottom with maybe some rain run off. We get some stringy algae around the edges but not to much.

Bought a test kit and last read was:
pH 7.5-8.0
Ammonia 0-0.25ppm
Nitrite 0ppm
Phosphate 0.50

We add extra water via the well which is only to top off up to the skimmer. There is an overflow weir that takes the heavy rain flow away down the slope so we do have a way to change out water. That said the prior owner ran the well nearly continuously to keep up with the leak, which we fixed. We haven’t run the pump to “change over” water yet.

We feed the Koi and other fish as best as we can make out as appropriate per the water temp. http://www.hikariusa.com/wp/feeding-coldwater-koi-basics/

We haven’t yet experienced any major algae blooms or seen any signs of a fish dying. One Koi was possibly killed by a Great Herron but the Koi was huge, about 20in long and looks to have probably jumped out of the pond about 2ft dying of air loss. Can’t really say if it was the birds fault.

The only odd thing was we had about 7-10 regular turtles, none snapping, living in the pond when we moved in. There was a time over the summer when over a period of 3 weeks, all of the resident turtles died unexpectedly, about July. We found them floating on the surface dead. There were no dead fish or other things out of place. It wasn’t particularly hot. The local Koi association said there was what could have possibly been blue algae? We never tested the water. No turtles have returned since.

Long story, long I guess is we’re really would like to ensure we’re taking care of the pond and if possible improving the viewing quality of the water to see more of the Koi. We can’t really see down past 4-6 inches or so.

Some posts here recommend Bogs, others tens of thousands of dollars worth of filters.

We have the space to do set the pond up right.

We’re pretty cost conscious, hard working and like projects. Also would prefer to keep the Koi and other fish as our kids and their friends enjoy catching/releasing.

Thanks in advance and look forward to the groups advice.

Cheers

 

[Lisak1]

Wow! What a pond! And fully lined? That's a rarity in a pond that size!

The runoff into the pond is troubling, if you're trying to control water clarity. How did they finish the edges? If you're up for the job, it may be helpful long term to re-sculpt the edges to create a berm around the pond to keep water from flowing into the pond from the surrounding landscape. While it is helpful for keeping the pond full, it may also be affecting water clarity. And if that grass is being fertilized or weed killer is added, you're contaminating the pond on a regular basis, and possibly contributing to algae growth.

I'd be curious to see how much organic material has built up in the bottom of the pond - I doubt anyone has been scooping leaves from THAT monster!

To figure out how to clear the water, you first need to figure out why it's murky. If you scooped out a glass or jar full of water, would the murk settle to the bottom and leave clear water at the top? Or is it overall generally murky and stays that way? In the first case, you'd want to add more mechanical filtration; in the second case, you'd need more biological filtration. It may be suspended debris that you're seeing that the fish and aerators are just constantly stirring up, or it may be floating single cell algae.

 

[addy1]

Good advice @Lisak1

What a neat pond and huge! Filtration I would go with a huge bog, great plants and filters well.

 

[Jhn]

Agree with both @addy1 and @Lisak1, redoing the edge of the pond and creating a huge bog would be the route I would go as well.

 

[rubyduby]

Agree with both @addy1 and @Lisak1, redoing the edge of the pond and creating a huge bog would be the route I would go as well.

Yes, both have given great advice...Bog and building up the edge! I had a 16,000 gallon pond when I lived in Virginia that would never clear up because the sides were not built up enough and run off would seep in whenever it rained. I hated not being able to see my fish unless they came up to feed...

 

[fishlips]

This is a "dirt pond" even tho there is a liner, dirt falls in every time it rains. The water has to be green for the safety of the fish.

Depending on how clear you would like the water is deciding factor of the actions needed to be taken.

If you're just looking to see the koi on the surface during feeding time then I would suggest a good spring cleaning. I would think it's thick with sludge. But the water will have to stay green.

If your trying to get nice clear water then what every one is saying is correct "edges and bog". At that size you might need more the one bog and some some big pumps.

Then again using the air pump to power a small bog might be clean enough.

If it was my pond I would drain some water do a fish count, may be lower the fish load and clean down to the liner. Test the well water and fill it up. Then let it go for the summer.

Nothing you posted is rasing a red flag. Your fish should be safe even in the "dirty water".

 

[j.w]

That is so huge and do you ever have to watch out for gators?

 

[Martin padgett]

Wow! What a pond! And fully lined? That's a rarity in a pond that size!

The runoff into the pond is troubling, if you're trying to control water clarity. How did they finish the edges? If you're up for the job, it may be helpful long term to re-sculpt the edges to create a berm around the pond to keep water from flowing into the pond from the surrounding landscape. While it is helpful for keeping the pond full, it may also be affecting water clarity. And if that grass is being fertilized or weed killer is added, you're contaminating the pond on a regular basis, and possibly contributing to algae growth.

I'd be curious to see how much organic material has built up in the bottom of the pond - I doubt anyone has been scooping leaves from THAT monster!

To figure out how to clear the water, you first need to figure out why it's murky. If you scooped out a glass or jar full of water, would the murk settle to the bottom and leave clear water at the top? Or is it overall generally murky and stays that way? In the first case, you'd want to add more mechanical filtration; in the second case, you'd need more biological filtration. It may be suspended debris that you're seeing that the fish and aerators are just constantly stirring up, or it may be floating single cell algae.

 

[Martin padgett]

I built a pond of about the same size last year. I added a 9’x12’x3’. Bog filter on mine. It’s crystal clear most days. Rain will get it murky, but clears quickly. You need a BOG. A world of difference