Pond Boss Forums GENERAL QUESTIONS Muddy water Alum Kicks Clay Butt!

Here is a very cool PDF on treating some lakes with storm run-off with Alum such as Lake Apopka.

Alum Treated Lake Sites

Thanks for the clarification. So those charts are the same but I don't think the other one stated what slurry actually meant, unless I missed it.

So if a .1 gram test worked in a 1 gallon container, what would that equate as pounds per acre/ft?

Also you are saying that any excess Alum introduced doesn't have any advantages long term?

Do I get to look forward to applying Alum each year to deal with more inflow of dirty water?

.1 grams x 325,828 gallons/ac. ft.=32582.8 grams/ac. ft

32582.8 grams/ 1000 grams= 32.5828 kilograms

32.5828 kg. x 2.2 lbs/kg.= 71.833 lbs per acre foot

Thanks Chris! My head still hurts from the last post!

One other thing to note about alum---DO NOT USE ALUM IF THE PH IS 6.0 OR LESS!!!! Above 6.0 the aluminum falls to the bottom with the floc and cannot dissolve.

Going fairly heavy on the alum dose CAN provide benefits. But this is not generally recommended.

Some of the benefits include....

First, it will cause the suspended clay and algae to form bigger and heavier clumps and clear much faster. The bigger clumps are also much less likly to re-suspend.

Second. Excess alum will bind to any Phosphorus(sp) which in turn will reduce FA growth. This may also reduce desirable plant growth too.

Third. Alum will usually be needed in concentrations that kill snails.

Fourth. A heavier concentration will leave the water "positively" charged and will floc any negatively charged clay entering the water column until the charge is neutrilezed.

As for long term benefits, to quote Bill Cody< that all depends. Some studies show alum working for 15 years, others say there is NO risidual effect. I think the bottom line is that you will need to prevent any new clay from entering the pond or else it will be an ongoing problem. If the original dose is adequate, the clay already in the pond will usually not re-suspend.

Good job, Chris. Neo, also, you should add at least 40% by weight of hydrated lime immediately after the alum to maintain the original ph. After adding alum followed by quick lime, my pond always clears up quickly after the dog runs/swims around in the shallow end. After a 4 inch rain in 2 hrs. last wk., the pond cleared up quickly. Alum was added in March.

Additional alum sources recommended by a nearby water treatment plant:

"try Univar USA, Inc. 1-800-947-9264, or Chemical Services Inc. 937-898-7602, Bonded Chemical Corp @ 614-777-9240, Sal Chemical @ 800-879-1725"

Rainman, what was the approximate ratio of water to powdered alum? I think I'll only need to use about 200lbs of alum and followed by 100lbs of hydrated lime to be safe. I'm estimating this for about 3.33 acre feet since my 1/2 acre pond is couple of feet low right now. Just trying to an idea of how much water I'll be pumping to appropriately scale equipment.

Just to be clear, Alum is aluminum potassium sulfate right?

Wikipedia says hydrated aluminum potassium sulfate with the formula KAl(SO4)

Ryan, the alum we are referring to is NOT Aluminum Potassium Sulfate (KAl(SO4)), it is Aluminum Sulfate (Al2(SO4)3).

Also, the best mix ratio is 10 pounds water to 1 pound alum. You will be fine with 2 gallons water to each pound of alum. Be sure to add HYDRATED lime while applying the alum.

DO NOT MIX THE ALUM AND HYDRATED LIME IN THE SAME CONTAINER!!!! You will get a thick paste!

I usually pour in the Hydrated lime straight out of the bag from the side of the boat while I am spraying the alum slurry. The lime will disperse quickly without pre-mixing.

If anyone wants to talk to me about applying alum, just send me a PM.

Most large chemical companies supply alum at a very reasonable price. I use GS Robins, but you can contact any water treatment plant to find the local supplier. I don't, but you SHOULD use a good dust mask when pouring the dry alum and hydrated lime. One whiff of the dust will teach you not to breath in while pouring.

Did the Alum treatment thing today & think it went ok. It did lower the pH from 7 to 6.5 in spite of 500lbs lime. I put out 1000lbs of Alum on about 2 1/2 surface acres. My set up was to use pontoon boat with 80 gal water trough to mix the Alum in



I tied a float to the suction side, threw it overboard, then filled the trough with 50 gal water



Then added 50lb Alum & mixed it with an oar.



Then put the suction side in the trough & sprayed the slurry over the pond surface



The water was starting to clear after about 5 hrs(went from 3" to 9" visibility)of spraying, so will interested to see how it looks this weekend..du

Nice setup and method David!

Question.. Is that a bag of limestone or Hydrated lime? I'm asking bcause if it is limestone (ag lime), it will be very, very slow to offset the ph.

If you decide you need to add more alum, put the discharge near the prop wash or use a nozzle to "fan" the spray. The alum tends to drop quickly with the flock and the wider the spray, the better the floc.

Looks good, and I hope it does great for you!

From the experiances I have had with applying the alum, you may need to use another thousand pounds to get ALL the clay out of suspension for the best, longest lasting results.

Rainman, all very observant, good points. Half the lime was hydrated & half was ag(had on hand). I did buy another 1000lb Alum anticipating just what you suggested. The picture of the hose was for picture-taking only(by myself) & I did spray it like you were watering the yard, BTW, that stuff really burns the eyes on contact..du

I take it these heavy doses of alum also bind up the planktonic algae too. Is the alum simply removing the planktonic algae or is it also reducing the nutrients in the water?

IIRC it binds phosphorus (?).

Ryan Freeze, this article explains some of what Alum does in pond water http://www.minneapolisparks.org/default.asp?PageID=832

That's a good article.

What if I waited until the pond froze over and spread the alum and hydrated lime over the ice evenly with my fertilizer spreader? Would it mix enough as the pond thawed to do it's job?

Good question Ryan.

I'm sure it would mix, but probably wouldn't work since tyhe ice will melt slowly and in differant areas. As one area melted, untreated water would fill the void left by the treated area.
If the aluminum didn't fall from the water column, it might work quite well.

You IIRC correctly sir!

Like many pond matters it is a question of balance. WRT the article above it repeats a misconception as to recreational ponds , that is if you want fish. Removing all the P by bonding with Alum is not a good idea for the food chain. No P - no plankton (bottom of the food chain). There is usually one big difference between fish ponds and waste water treatment ponds - one is good for fishing the other not.

I like fish so IMO alum is not the way to treat FA. Alum when used correctly is a good tool to treat clay turbidity.

I could not agree more! Used the article reference only to clear up up how Alum affected phytoplankton, but not endorse it as a method for controlling it...du

david u good article and discussion of alum. Thanks for posting it. My comment was to remind those here with a goal of creating a pond that looks like a swimming pool with lots of big fish in it that some goals are hard accomplish. I knew that you were not advocating alum to get rid of FA. Just did not want those viewers with desperate FA problems to think it was an easy FA fix without consequences.

Everything in moderation, as they say.

Clay turbidity in my pond was horrible. I added alum until the turbidity is down to an almost acceptable level, and decided not to add more. I'm enjoying an algae and mostly weed free pond for now, until it finishes clearing naturally.

bobad can you comment on your alkalinity and fertility ? My guess is that your lack of FA is not from no P (i.e. the alum binding all the P into a non-soluble form).

I am just guessing, but I think it's from clay turbidity. When the pond is down about 12-14", I have about 16-18" visibility. When it's near full pool, as it's been for most of the past year, visibility is only ~12". I can see a little algae in the shallows, but not much. I have applied enough lime and gypsum to have a bit of alkalinity, but have never tested. Since my pond is basically a sky pond, fertility should be fairly low. I have only added 2 bags of 13-13-13 in 2 years.