Pond Boss Forums Thread Like Summary - Alum Kicks Clay Butt!

Did you ever wonder what Aluminum Sulphate (Alum) will do to help clear suspended clay in a pond? Maybe these photos will help!

I started the morning with 3-5 inches of secchi visability.

The first 2 pictures are older shots from spring of 2007. The next 2 pictures are from the morning I put in the Alum The next 6 pictures were taken about 1 hour apart beginning 6 hours after the Alum application was done. It took 3 hours to mix and apply the Alum from a small boat using a 40 gallon sprayer. 1200 pounds of Alum and 600 pounds of Hydrated Lime were mixed with pond water and surface sprayed onto approximately 20 acrefeet of water. NOTE: the pond in reality is 1.48 acres (see below).












The clarity differance is absolutely stunning!!! secchi reading after 24 hours.....................over 72 inches (I only had a 6 foot rope) I haven't been back to the pond in over a month since the Alum was applied. I hope after the last 8 inches of rain that it has remained clear and that a good bloom has begun.

Rainman hint from 3-11-09:
If not using a sprayer, but ARE using a boat(gas or trolling motor) Mixing the alum into a slurry in a 5 gallon bucket first before pouring into the propwash will work better. Be sure to add 50% of HYDRATED lime seperately to keep the PH from dropping much.

As you only have about 1.3 ace/ft of water, I'd suggest 100 pounds of alum and 50 pounds of hydrated lime. If it doesn't clear in 24 hours, add 50 more pounds of alum, Hy Lime could be optional on the second app.

The Cutrine+ will knock any planktonic or algal bloom down, as it breaks down, the Phos and Nitrogen will be released allowing the Phos to be locked up by the Alum.
60lbs/ac ft is good for "some" Phos being locked up with a small amount of colloidal clay but I think that's about 100lbs per ac ft short in my experience. I've used this method several times now and I've found 125-150lbs per ac ft is best in most cases, I've used as much as 200lbs per ac ft with no problems..
Have some hydrated lime on hand in case you get a large pH drop,. It adds calcium, has the power to add more negatively charged ions to lock up even more elements and sink it. You don't have to mix the hydrated lime in a slurry either

The cost of alum is really very cheap compared to other means like lime, gypsum, etc. General chemical is the primary mixer of alum, nearly all other companies buy from GenChem. You can email/call GenChem for a supplier near you. Cost will rang from 30 to 37 cents per pound. Most chemical suppliers require a $100 minimum purchase. Tell them you are a ranch (just use your initials such as R & S Ranch) otherwise you may have trouble getting them to sell to you. As for PH crash it is not nearly as big a concern as stated, BUT possible, so spend the extra $5 per 50lb pound bag and mix it in at half the weight of alum applied to be safe (That ratio makes it nearly ph neutral) The "trick" is to be truly effective is to pre mix the alum anywhere from 5:1 to 10:1 water to alum and SPRAY the mix evenly over the water. Dumping the alum in will not mix and you will waste your money (just as I did twice). If you have questions, send me a PM with your phone# and I will be glad to tell you more.

Rex

Burgermeister,

I raised sheperds for years for the military and I searched for this one for 2 years. He came from a litter in Kansas City.
BTW he is 135lbs---60lbs bigger than the breed standard. 6' 2" from tip of nose to tip of tail!

Tom G, If you have a pool supply store near you, they will do a ph and alkilinity test for free. If you have reasonable alkilinity, the alum will be buffered to where ph won't be a factor. Alum is not really very acidic and can be mixed in concentration with bare hands and not cause skin irritation (from personal experiance). I feel the lime is always a cheap insurance and can be spead dry either before or after applying the alum (I prefer after) also, I use pond water to make the alum slurry.

Whoa! That's a big difference between the "recommended" charts.

The chart that EWest posted stated the HIGHEST ratio test was 0.5 grams of Alum with a 5 gallon bucket, which would be 0.1 grams of Alum with a 1 gallon bucket.

The chart David U posted above stated the LOWEST ratio test was 1 tablespoon of Alum with a 1 gallon bucket.

I had purchased a digital scale which will measure down to 1/100th of a gram (0.00). This allowed me to perform my test in a 1 gallon container instead of 5 gallon buckets.

I can tell you that 1/8th of a TEASPOON of Alum weights around 0.83 grams, while 1 TBSP (tablespoon) weights 24 grams!

BIG DIFFERENCE!!!!

Why are these so far off from each other????

I can also tell you that I had a pH level of 7.8 and using 1 gram of Alum in a 1 gallon bucket crashed the pH to 6.2.

Neo, the COMPARISONS you give are not very differant at all. The link David U gives uses a teaspoon of SLURRY (1 teaspoon alum MIXED in 1 Gallon of water) and THEN using a teaspoon of the SLURRY MIX. 1 Gallon equals 768 teaspoons.

Using the weights that you provided for the alum, 1 teaspoon of alum should weigh 6.64 grams (.015 pounds). By dividing that 6.64 grams by 768 you get .00865 (rounded) grams per teaspoon of slurry mixed into the Gallon of test water.

By comparison, the chart showing .2 gram per FIVE gallons equals .04 gram per gallon. Since the alum becomes a slurry and never fully dissolves, the effective, DISSOLVED alum concentrations are very close in both tests.

The slurry test is more accurate because it uses the "dissolved" alum for results.

As for the APPLICATION rates, 30 pounds of alum equals .000092 POUNDS of alum per GALLON of water when applied to ONE acrefoot of water (326,700 gallons)----FAR less than the TEST concentrations.

As far as SAFETY concentrations, a QUART of dill pickles has an average of 1/6th teaspoon of alum in it, or 1.1 grams per gallon, or .002425 pounds per gallon, which equates to a VERY safe application rate of over 792 pounds of alum per acrefoot of water. Drinking water that has been treated with alum may contain a maximum final concentration of .000017 pounds per gallon after being filtered, but is treated at a rate of .0013 pounds per gallon (75 times greater than final product).

The only data I could find pertaining to aquatic life toxicity levels for aluminum sulfate found that quantities 1000 times greater than what is used to clear a pond only showed an "accumulation" of aluminum with no known problems.

Someone please check my math, but I am pretty sure it is accurate.

Also FWIW, alum becomes a solid and sinks to the bottom UNLESS the ph is lower than 6.0. Ph below 6.0 aluminum dissolves and becomes toxic to fish. Then again, a ph below 6.0 by itself is not too good for the fishies!

Now I need a vacation to let my brain cool down from recalling all the equations needed for this....

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.

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.

You should turn it off for about 48 hours. If you've used enough alum to get all the clay, the flocculation will have ceased by then. The floc will then slowly compress itself over time on the bottom. EVERYTHING in the pond will have a sediment layer on it untill the fish dust their house clean.

Best of luck Ryan, and take your time! try to apply the alum for water depth. Deeper water = more alum.

I ended up turning my aerator on about 8 hours after the application. Some of the floc is floating on the surface where the wind piled it up. Visablilty last night was between 18" and 20". The fish were eating and no casualties so far.

Man, talk about being REALLY bummed out!!

The wife has recovered enough that we went to our property to see the pond for the first time since early July. The Alum had been applied in very late June and since the application the rain guage shows 15" of rain have fallen and the pond was down about 3 feet. I fear there may be another leak.

The pond is as muddy or worse than it was before the alum was applied! I gathered a sample in a jar to see if it would clear. IT DIDN'T! My CC have spawned successfully due to the turbidity and I was hoping they were the cause.

I am considering one more application of alum, 2000 pounds this time. and purchasing some floc logs as a maintainer of clarity.

Any one else have some thoughts on this problem, or should I just start managing the pond for catfish?