Pond Boss Forums GENERAL QUESTIONS Muddy water 1/4 acre Koi pond Alum results! Should I add more?

I did a Alum treatment on my 1/4 surface acre (2 acre ft) Koi pond 2 months ago. The water visibility went from 8" to about 30". The results were great. It went from a muddy brown to a blue green color and I can actually see the Koi now.

There are Bass and bluegill in the pond but we dont fish this pond. I would love for this water to be crystal clear.

Alum dosage rate was 400lbs total over 2 days (200lbs one day then 200lbs the next)

My question for all you is are there any down sides to another treatment for a Koi pond? Is there more of a risk of a PH crash if the water is already relatively clear?

The first pic is from during the first alum treatment. The second two are from after 400lbs of alum

Glad you got good results!

Part of the obstruction of visibility in a pond comes from electrically-charged clay particles and part comes from blooms of various living organisms.

The alum only works on the clay particles.

Do you have a swan as a permanent resident on your pond? Do you feed the koi, or do they stir up your bottom sediments when they get hungry?

Swan (and goose) poop is straight up fertilizer for the blooms in your pond. Extra koi food that they miss and lands on the bottom also becomes fertilizer. The poop from well-fed koi is also fertilizer. The more "sterile" you keep you pond, then the better visibility you will have. Obviously, you will have to choose your trade-offs, because you clearly do not want a sterile pond.

If you do decide to keep 100% of the existing animals that are "fertilizing" your pond, then you certainly want to eliminate any other sources of fertilization. Make sure no run off from fertilized yards reaches your pond, or from fertilized ag fields. Also, no fertilizer from stock animal wastes. Finally, it even helps to keep grass clippings, leaves, pine needles, etc. out of your pond. Those all have a slight fertilizer effect. Further, the organic material that is NOT broken down goes on to create organic muck on the bottom of your pond!

One other option to reduce your blooms might be some pond dyes. They work by reducing the sunlight in the water column available to the photosynthesizing organisms. There might be a possible delicate balance where you reduce the sunlight enough to affect the algae yet still get enough visible light through for your eyes such that you can get even deeper secchi disk readings. However, that may be quite difficult, and there will certainly be a color tint to your water. If there are some tints that you think would make your pond MORE attractive, then it might be worth you experimenting.

As to more alum treatments, I think you need to perform some periodic "jar tests". When your jar tests indicate the visibility problem is due to suspended clay, then you can consider another alum treatment.

I would also invest in a good water testing kit. I think you should have results in your file showing your pond chemistry when it is healthy and presumably can easily accept another alum treatment.

There are several good threads on jar tests and testing kits in the archives.

Good luck on your beautiful, clear pond! I think 30" visibility is pretty good, but you certainly have several options to go for more.

Firstly IMO your lack of water clarity is not caused MAINLY by water blooms. Koi are making or roiling the water to be murky and the bottom aeration mixing is helping a lot to keep the resuspended very tiny (0.3 to 3um) bottom dirt in suspension. Turn off the aeration for 3 to 6 weeks and watch how much more clear the water very gradually becomes; maybe close to 2-3 ft IF and IF you have no more than 2-4 koi in 1/4ac. Use a secchi disk to measure the water clarity for measurements and comparisons. See next.

With several or numerous koi in a 1/4 ac pond or any pond IMO and experience that does not have extremely large mechanical filtration the water will never be any more clear than around 3ft often it will be less of 6"-12" when the water is above 60F. The more koi present the muddier the water becomes. Your pond water is very likely relatively clear when the ice melts in Spring. This is because the koi are have been relatively dormant all late fall and winter with very little feeding activity when the water temperature drops below 45F and they do very little feeding due to cold water and their cold body temperature. Ice cover with no wind action nor carp feeding allows the suspended sediments to gradually settle toward the bottom. Thus when the ice melts the water is clearest of all year. As soon as the water warms and koi become actively feeding the water becomes more and more turbid. Watch for this to happen each Spring.

Realize that koi have exactly the same body features and anatomy as a river carp. I call koi aquatic rototillers and aquatic pigs. The Japanese worked with european and oriental carp (Cyprinus carpio) a few thousand years ago and selectively breed them to have all types of color with various body patterns . In reality,,, some of the offspring of Koi are drab color and have identical body color of river carp because their genealogy is river carp. Same drab color thing happens when breeding goldfish. Goldfish are NOT koi; the two are different species. River carp have a suction type protrusable mouth that they use to dig 1"-3" deep into the sediments searching for food items that live in and on the sediments. Their feeding activity stirs and roils the bottom sediments thus creating murky, muddy water behind them as they feed. Koi do not have stomachs, just intestines, thus they cannot binge feed thus they feed frequently and hourly searching the bottom sediments for food. This frequent feeding activity roils the bottom sediments. If the pond has aeration, the circulation activity of the aerator helps keep the very tiny resuspended sediments in suspension making or keeping the water even more turbid. Try not running the aerator and see and measure (secchi disk) what happens to water clarity.

IMO the good thing about koi is their bottom rooting and feeding activities helps aerate and mix the bottom sediments. The fewer koi / carp that you have in the pond the clearer the water will be. I have proven this many times. Clear koi ponds have lots and lots of mechanical water filtration to minimize all the muddy conditions crated by koi. Many of the clear (4-7ft clarity) koi ponds that you see have little to no mud /clay sediment in the bottom and have extensive mechanical filtration. .

Back to your original question - alum is aluminum sulfate. Each alum treatment for making the 3 ft of clarity will be VERY temporary due to actively feeding koi. Aluminum is a heavy metal and does accumulate in the bottom sediments with each usage. Heavy metals do not decompose nor rot up. Too much heavy metal even aluminum when used too frequently can later be an ecological toxic problem.

The good news is your pond does not have weed and algae problems because the murky water from the koi activity keeps sunlight penetration to a minimum so plants don't get enough light to grow well.

Thanks for the great info. I am aware that the Koi forage constantly and dig into the clay. I changed the schedule of the automatic feeder to 5 short times per day instead of two to hopefully keep them occupied.

The Koi seem to prefer to dig holes around the shore that does not have rock in 6"-18" of water. What are your opinions on adding rock to that shore line? You think they will just forage in deeper water?

My aerators are sitting on the bottom so I am going to raise them up.

I purchased the property in January of this year and noticed then the water was very brown. It was a darker brown but still about the same visibility.

There are 13- 24"-28" Koi, 7- 10"-13" Koi and 3 -28"-32" grass carp.

The grass carp keep the pond 100% free of any aquatic plants. I feel that may also add to the problem. There is nothing holding the bottom substrate in place.

This may be a question for another thread but is there a happy median with grass carp to have a reasonable amount plant life or is it all or nothing? My other pond on the property is 1.25 acres and has 10-12 full grown grass carp. There is not a single weed growing there either.

I forgot to add that the swans are decoys. They do absolutely nothing to keep geese out. Only way to get rid of them is chase them out.

A 12 gauge shotgun works best

The bigger the koi get the more muddy water they create. There may be enough koi to do enough in cold water to keep the water clarity 2ft soon after after ice out. IMO 3 grass carp by themselves in 1/4 ac would result in water clarity of around 2 to 3 ft. Too many grass carp can also reduce water clarity. Koi also help to keep sediments rototilled and mixed keeping weeds and algae from growing.

I don't think that moving the air diffusers up off the bottom will not do much to improve water clarity. Try it and see what happens and report back here on this thread. We can learn from your testing. The major or strongest mixing of pond water is at the top surface boil action as it spreads and pushes outward the water entrained from the upwelling water column.

You think they (koi) will just forage in deeper water? Yes - deeper water foraging. It is instinctive for koi to root and dig in the sediments where ever they can find food. Feeding them pellets might keep them more full of food resulting in less digging action????

If it was my pond I would watch YouTube videos how to catch carp. Bait them regularly (daily) and fish in the baited areas on weekends and remove as many as you can catch. Have a carp fishing party for family (friends) with prizes for biggest smallest and most koi caught. The fewer and smaller the koi are the less turbidity will be in the pond. IMO a 1/4 pond should have only one large koi and one grass carp. Based on plant / algae growth, One or two can always be added if needed but it is very very hard to get them out.

In my experience, the plastic swans do not poop much at all. The geese on the other hand ...

Bill Cody is one of our actual experts. I always seem to learn at least one new thing from each of his posts, even for things that do not relate to my ponds at all. When he is giving advice on your pond, probably good advice to follow rigorously!

I don't want to get rid of the koi. My goal is to have a mud bottom koi pond with a reasonable amount of visibility. I will update this thread if the water gets turbid again.

Koi can become pets. IMO and lengthy experience, with several decent sized koi in a mud bottom 1/4 acre pond with aeration,, expect it to always be turbid often with visibilities of 12"-14" or less no matter how often you chemically try to make the water clear. Koi do what koi do. If you want a clear water koi pond just build a back yard liner pond of any size that you want plus install appropriate good filtration system.