Where Can I Get Gypsum

[happyjune]

Waters Edge has been very helpfull, but I am still lost, I can't seem to find a supplier, now 18 plant supply shops, I really am wondering about why the hell I am in this county. Gypsum CaSO4.2H20 is available where you find it.

Sheet rock scraps along the highway, in trash dump piles and at building supply stores.

Depending on your local geology, you may find deposits.

I have several low grade dirty deposits in my area,

which doesn't hurt the fertilizer value of it.

One place has tiny clay chips and another has round stones & gravel.

Look for road cuts where the white color bank has dissolved away.

Gypsum attracts water and is somewhat water soluble,

so it disappears with the water quicker than soil.

The Lime you mention is very strong, pH 15

it's Calcium Hydroxide Ca(OH)2 Poon Kao Cement White

If you want the more gentle form get Limestone dust pH 8.3

This topic just came up a few days ago in an earlier thread,

so I won't repeat that information here.

Poon Kao seems cheap to you as compared to Oz,

but Limestone dust is quite literally "dirt" cheap

Even Limestone dust is too strong if applied in excess

If your soil pH is already high enough but you feel you need Calcium,

then of course Gypsum is the easy answer.

[IsaanAussie]

Try the local feed and fertiliser store YIPSUM. Hey HappyJ, you are here because you want to be, just like the rest of us.

[happyjune]

Yeah, I know here by choice ........... sometimes what I consider logical and the most basic of tasks, seem harder than launching a manned space rocket.

I will start hitting up feed stores.

Anyone know the typical cost?

Cheers.

[BAYBOY]

Re Gypsum.

Company that produces gypsum for agricultural end use. D.K.T. Co, Ltd.

29/4 J Building Phaholyothin 3 Phayathai, Bangkok 10400

tel. 0-2272-4051-30 fax 0-2270-0879

Website www.dktgypsum.com

E-mail [email protected]

Their product is called Green Cal, and usually can be bought from shops selling fertilisers.

I feed several bags to newly planted mangoes a couple of years ago. The trees have grown very well.

CHEERS

BAYBOY

[WatersEdge]

Hi happyjune,

How much Gypsum do you need and where are you located?

Do you have Limestone available in your area?

There's more than one direction to approach this.

You can buy Sulfuric Acid 98% H2SO4 for around B14/kg,

mix it with limestone, and poof, you have Gypsum

CaCO3 + H2SO4 => CaSO4 + CO2 + H2O

It's going to be more expensive this way

than by picking up sheetrock scrap,

but it gives you a perfectly fine slurry

If you have high pH soil you spray the acid on the soil

and the same reaction happens in place

The second method if you have high pH soil is to use

Ammonium Sulfate 21-0-0 + 24S fertilizer.

When the plant consumes the Ammonia the Sulfate is left behind.

It will then bond with available Calcium to form Gypsum.

[fredge45]

We tried giving this company a call with a Thai speaker. They were most accommodating. At that time we were looking for a supplier in Chiang Mai but they said there wasn't one carrying their products. But there is one in Chom Thong, where we live, who has a warehouse full of the stuff - both in granular and powdered form. Seems that the hilltribe farmers have found that applying gypsum is really good in their clay soils.

You don't say where you live so I don't know if this will help you or not...

Re Gypsum.

Company that produces gypsum for agricultural end use. D.K.T. Co, Ltd.

29/4 J Building Phaholyothin 3 Phayathai, Bangkok 10400

tel. 0-2272-4051-30 fax 0-2270-0879

Website www.dktgypsum.com

E-mail [email protected]

Their product is called Green Cal, and usually can be bought from shops selling fertilisers.

I feed several bags to newly planted mangoes a couple of years ago. The trees have grown very well.

CHEERS

BAYBOY

[thaipod]

This is good to find out as I've been trying to find gypsum for some time .

I recently had our water ways between our fruit trees dug out in hope of the workers packing the sides of the channels, but they dumped lot's of clay on the land and now worried about surface water penertration. I'm hoping this will help break down the clay.

[WatersEdge]

It will not break down clay by surface application.

It has to be plowed into the clay, or scattered over the broken clay surface after plowing.

It is very mildly water soluble, so it would very slowly leach down into the soil.

But if there is runoff it would be carried away just as quickly.

In order to significantly break the clay, you need a huge amount of Gypsum.

Wonder when the Chom Tong farmers will discover it in natural deposits.

[fredge45]

It will not break down clay by surface application.

It has to be plowed into the clay, or scattered over the broken clay surface after plowing.

It is very mildly water soluble, so it would very slowly leach down into the soil.

But if there is runoff it would be carried away just as quickly.

In order to significantly break the clay, you need a huge amount of Gypsum.

Wonder when the Chom Tong farmers will discover it in natural deposits.

I suppose the Chom Thong farmers will be happy follow your excellent guidance once you come along to display some of it... with a handy barrel of sulfuric acid as well? From what I have been able to find out, the mining/processing of gypsum in Thailand occurs mostly in the southern parts of the country.

My experience has been that it doesn't really take all that much gypsum, incorporated into the soil, to make a significant breakdown of the clays. But I'm a rank amateur in this.

[WatersEdge]

Hi BAYBOY

What does the DKT Gypsum cost?

[Khonwan]

Hi WatersEdge. I’ve been using Greencal (DKT gypsum) for my pond for quite some time (have previously posted on it). Usually retails at 150 baht for 25kg though I bought 50 bags last year from my usual ag supplier @ a deep discounted 120 baht.

Rgds

Khonwan

[WatersEdge]

Thanks Khonwan,

B150 / 25 kg => B6.00 / kg Retail

B120 / 25 kg => B4.80 / kg @ 50 bag Volume

50 x 25 kg => 1,250 kg

This price scale makes it cost effective

to apply Sulfuric Acid 98% to Rock Phosphate 13.2%P (Elemental),

so that the Phosphorous is completely water soluble in the form of Phosphoric Acid,

with Gypsum as the byproduct.

So if your application also calls for Phosphorous,

you need not even separate the products

Mix the correct weights of each into a plastic tub, and let it work a few hours.

I am so curious on the purpose of Gypsum in a pond.

As pH Buffer?

I have somewhere in mind that fish don't like Sulfur

You say you have posted on the topic...I can go hunt it from your profile

[Khonwan]

WatersEdge

I use it as a water clarifier.

I found this post from me 3 years ago: but the referred to D.K.T links appear to no longer work: their site has obviously been cyber attacked. I believe I have a downloaded copy of D.K.T’s. literature in an archive of a hard disk from an old pc – I’ll try to find it.

Rgds

Khonwan

[Khonwan]

Water Treatment Considerations

© 2001 D.K.T Co.,Ltd.

Fish have three basic requirements for survival and optimum growth:

1. Clean Water

2. Oxygen

3. High protein food

Water Quality

In any other agricultural operation including plants and livestock such as poultry, cattle, horses, or hogs, a person would not even consider trying to grow these species in a dark room with no food, water, oxygen or sunshine. Yet, these same people will excavate an one acre pond, stock the pond with thousands of dollars of expensive hybrid fish. They expect to grow these fish in turbid water (no sunshine), with no food (fish have to eat too), no oxygen ( the atmosphere has 20.9% oxygen - water can only hold 8-10 parts per million - ppm ), and water with no minerals at extreme pH levels. They are then surprised when all the fish die or do not grow.

Water quality control for aquaculture facilities, either commercial operations or backyard ponds is a specialized science but is relatively simple and can be accomplished by people with little or no scientific background or experience. Certain parameters must be maintained for optimum growth of aquatic species such as sport fish. The most important parameters include the following:

pH and alkalinity

Hardness (calcium and magnesium) levels

Water clarity

Oxygen level

Nutrient level

pH and Alkalinity

Optimum pH level for aquaculture facilities is 7.0 - 8.5. The problem with pH control is that pH levels in a pond or lake can vary significantly over a given 24 hour period due to respiration and photosynthesis. Carbon dioxide, which is produced by respiration of aquatic life combines with water to form carbonic acid, which lowers water pH. Algae utilize carbon dioxide during the daylight hours, which reduces carbon dioxide levels and increases pH during daylight hours. At night, photosynthesis stops and pH levels decrease.

The only practical method of managing abnormal pH fluctuations is to increase the alkalinity of the water. Alkalinity (the ability to absorb acid) buffers the water and stabilizes the water against pH fluctuations. Increasing the alkalinity of water can be accomplished in a variety of ways but only one is safe for aquaculture facilities. The various compounds which can raise the alkalinity of water are as follows:

1. Hydroxides such as sodium or calcium hydroxide.

2. Carbonate compounds such as sodium or calcium carbonate.

3. Bicarbonates such as sodium bicarbonate. (baking soda)

Of all of the above, only sodium bicarbonate (baking soda) is safe or practical for aquaculture facilities. The hydroxide compounds are too alkaline and can cause locally high pH condition when added to water. The sodium carbonate is also very alkaline and can also cause locally high pH conditions. The Calcium carbonate (agricultural lime) can take months to dissolve, making control difficult if not impossible. Sodium bicarbonate (baking soda) is very soluble in water and will not cause locally high pH levels. It is available from most commodity chemical suppliers and/or aquaculture suppliers for about $0.03/lb. in 50 lb. bags.

The desirable alkalinity range for an aquaculture facility is 50-150 ppm alkalinity. This will assure a ph range of 7.5 - 8.5 and eliminate pH fluctuations.

Analysis of alkalinity of pond water is a relatively easy procedure. A small hand held digital titrator is available from Hach Chemical Co. (1-800-227-4224) for $165.00. (Catalog #22709-00) In addition you will need a reagent set (catalog #22719-00) $32.00

The analysis procedure is very simple. Instructions are included with the test kit. You simply measure 100 cc of sample and pour into the titrating flask. Add 1 packet of indicator dye. Using the titrator, and after zeroing the titrator counter, add titrant until the color changes. The alkalinity level is read directly off the titrator as ppm alkalinity.

Determining how much sodium bicarbonate to add to a pond is also very simple.

1. Multiply the pond length X the pond width X the pond depth.

2. That number is the cubic feet of water.

3. Multiply cubic feet X 7.5 X 8.34

4. That number is pounds of water.

Example: 100 feet long, 50 feet wide, 5 feet deep.

100 X 50 X 5 = 25,000 cubic feet

25,000 cubic feet X 7.5 gallons per cubic foot = 187,500 gallons

187,500 gallons X 8.34 = 1,563,750 lbs. water

= 1.565750 million pounds

Now that you know how many million pounds of water is in the pond, analyze the pond water for alkalinity level. For example if the alkalinity level is 50 ppm and it is desired to elevate the alkalinity to 100 ppm, simply multiply the alkalinity difference with the following numbers.

100 ppm (desired alkalinity)

- 50 ppm (pond alkalinity)

50 ppm difference

50 ppm difference divided by 0.6 (factor) = 83.33 ppm sodium bicarbonate required per million lbs. water.

83.33 X 1.5675 million lbs. of water = 130.6 lbs of sodium bicarbonate required to raise the alkalinity from 50 ppm to 100 ppm.

Hardness level (calcium and magnesium)

Fish as well as other aquatic and land based species need calcium for proper growth and development. The minimum calcium level is 20 ppm but more is better. Water which is low in hardness compounds will tend to remain muddy or high in suspended solids. There are many compounds which can be utilized for increasing the hardness level of water. These include the following:

Calcium Chloride

Calcium Carbonate (Agricultural Lime)

Calcium and Magnesium Carbonate (Dolimitic Lime)

Calcium Hydroxide (Hydrated Lime)

Calcium Sulfate (Gypsum)

Of all of the above, Calcium Sulfate (Gypsum) is the best choice. It is the cheapest, safest, and much easier to dissolve than either Agricultural or Dolomitic lime. While calcium chloride dissolves easily, it is more expensive and is hard to store since it absorbs water from the atmosphere.

Care must be taken to purchase agricultural grade gypsum which is produced from a mining operation. Gypsum which is a by-product of phosphoric acid manufacturing has some residual acid and will depress the pH and alkalinity levels of a pond. It always recommended to check the pH of a sample which has been added to water before use. Also do not use gypsum wallboard or gypsum powder or slurry which is formulated for wallboard repair. This type gypsum has fiberglass fibers which can kill fish when circulated through their gills.

The analysis of hardness (calcium and magnesium) in water is also a very simple analysis. The same digital titrator utilized for the alkalinity analysis if utilized. A reagent kit for total hardness is simply substituted for the alkalinity kit. The reagent test kit for hardness is also available from Hach Chemical Co. Order reagent test kit # 24487-00 ($40.40).

The analytical procedure is also included in the Digital titrator manual. Simply measure 100 cc of sample and pour into the titrating flask. Add a dropper of hardness buffer and one packet of hardness indicator and mix. Install the hardness titrator cartridge into the titrator and set the counter to zero. Add hardness titrating solution until the sample goes from pink to blue. The hardness level is read off the titrator as ppm hardness.

Reagents are also included in the reagent test kit to analyze for calcium hardness only. Simply use the calcium buffer and the calcium indicator. The endpoint on calcium is more difficult to see than the total hardness since the color change is from pink to violet. If both the total hardness and the calcium hardness are analyzed, the magnesium can be calculated by subtracting the calcium hardness from the total hardness.

Calculating the amount of Gypsum to utilize to increase the hardness level of pond water is accomplished as follows:

ppm hardness level increase desired X 1.72 = pounds/gypsum per million pounds of water.

Million pounds of water X pounds of gypsum per million pounds of water = pounds of gypsum required.

Using the same pond size as we used for the alkalinity calculations:

50 ppm X 1.72 = 86 ppm gypsum required to raise hardness by 50 ppm.

86 ppm x 1.5675 million pounds of water = 134.8 lbs of gypsum.

Water Clarity

The primary problem with aquaculture ponds and facilities, especially in the southern and eastern parts of the country is water clarity. This is primarily due to the low level of hardness compounds in the soil in these areas. Good water clarity is essential for the cultivation of sport fish such as bass. While bream, catfish, and hybrid striped bass will eat commercial fish food, bass require live food. If they cannot see their food, they cannot eat. Ideal depth of visibility is about 18 inches.

Water clarity problems are primarily caused by suspended clay particles. Clay particles are very small (colloidal) suspensions in water. The reason clay particles do not settle in water is because they have a negative electrostatic charges attached. It's like having a group of similar magnets; they repel each other. Clarification of water containing clay particles is accomplished by adding chemicals to the water which have opposite charges (positive). Partial neutralization of the negative charges on the clay particles allows the small particles to come together (agglomerate) and settle quickly. A number of compounds are capable of clarifying water but only one is completely safe and desirable for use in aquaculture facilities. These materials include the following:

Iron salts such as ferric and ferrous sulfate and ferric chloride.

Aluminum salts such as alum (aluminum sulfate)

Calcium salts such as calcium sulfate (gypsum) and other calcium salts.

Organic materials from decomposed vegetation (tannins, lignins, etc.)

Organic synthetic polyelectrolytes

The iron salts are not desirable since they lower ph and are not very effective in the pH ranges desired in aquaculture facilities and the aluminium salts also have a significant lowering effect on pH. Organic materials such as decayed vegetation (hay is normally utilized) will work but have the side effect of coloring the water a deep brown color as well as depleting the oxygen supply during decomposition. The synthetic polyelectrolytes can be utilized to clarify water before fish are added to the pond. These materials cannot be utilized with fish in the pond since even low levels of overfeed would coat the fish's gills and prevent oxygen utilization.

Gypsum for Clarification of Aquaculture Ponds

The safest procedure for clarification of aquaculture facilities is to use agricultural grade powdered gypsum. ( calcium sulfate ) This type gypsum will not affect the pH or the alkalinity of the water and will clarify water as well as any of the undesirable components listed above. The key to the successful utilization of agricultural gypsum is to dissolve the material into the water. Even though the solubility of gypsum is much higher than other compounds such as agricultural lime ( calcium carbonate ) it still takes time and a correct procedure to dissolve the material. While the product is partly powder, some pellets and granules are present which must be dissolved in some of the available supplies. If you are lucky enough to be able to purchase the pure powdered form, all you have to do is to make a slurry with the powder and water and add to the pond water. Distributing to various parts of the pond will increase the speed of clarification.

If the product available to you is a combination of powder and granules, you'll need a small submersible pump to pump water from the pond, into a 5-30 gallon container with the gypsum in the container. Simply flow water from a hose connected to the pump into the bottom of the container containing the solid gypsum and allow the water to dissolve gypsum by up-flowing and overflowing into the pond. It is best to attach a 3-4 foot piece of pvc or metal pipe at the end of the hose which is placed in the gypsum container to keep flow distribution at the bottom of the container. Using a 10-15 gallon per minute pump running 24 hours per day, about 200 lbs. of gypsum per day can be dissolved utilizing this procedure. Most turbid waters which are a result of clay particles can be clarified utilizing 100 - 400 ppm (lbs. per million lbs. water)

For example, if a pond contained 1.5 million lbs. of water, you would need 150 to 600 lbs. of gypsum to clarify. Fortunately, gypsum is relatively cheap and is available for about 12-15 cents per pound in 40-50 lb bags.

Be aware that some varieties of gypsum contain up to 10% of materials which will not dissolve in water such as rocks and other minerals. If insoluble material is encountered, it should be discarded after a couple of days of flowing water through the material.

Oxygen Control

Oxygen control is probably the single most abused and overlooked aspect of aquaculture and responsible for the death of more fish than any other parameter. Fish can go without food for months but will die in minutes without oxygen. As indicated previously, the solubility of oxygen is in the range of 8-10 ppm (parts per million) at ambient temperatures. Fish thrive between 5-10 ppm or above. At about 3 ppm, fish will stop eating, at 2 ppm or less, they will come to the surface and gasp for air. At 1 ppm or less, fish will die, with the larger fish dying first.

Oxygen is more soluble in cold water than in hot water, therefore most fish kills due to oxygen depletion occur during the hot summer months of June, July, and August. Since the only source of oxygen in water is from the absorption from the atmosphere, the amount of surface turbulence or wave action in a pond will determine that pond's fish holding capacity in terms of oxygen depletion. A one surface acre pond, without supplemental aeration can only support 200-500 total pounds of fish without oxygen depletion problems during a hot, breezeless summer.

That same one acre pond can support up to 10,000 lbs. of fish with proper supplemental aeration equipment or at least 20 times more fish. Supplemental aeration also has the added advantage of removing undesirable dissolved gasses from water including ammonia and hydrogen sulfide.

Aeration utilizing circulating pumps is normally only 10% as efficient as floating surface aerators. The object is to circulate as much water as possible and break the water into the smallest droplets possible to get as close as possible to complete saturation of the water with oxygen. A circulating pump simply cannot accomplish this feat even if spray nozzles are utilized. The best recommendation which can be made in this area is to utilize aerators with the correct horsepower rating as recommended by a competent aerator manufacturer. My own personal preference in this area is an aerator manufactured by Ken's Hatchery and Fish Farm. The aerator is available from the following website: http://www.treytec.com/aquarius.htm. I have personally been successfully utilizing these aerators for over three years with complete satisfaction. These units also have very low maintenance requirements and operate at very low power consumption rates. The average monthly power cost in my area is $40-$50 per month when operated 24 hours per day during the summer.

Contrary to popular belief, most oxygen depletion problems do not occur during the hottest part of the day. Most oxygen depletion problems occur just before daylight. During daylight hours, algae and plankton produce oxygen into the water through photosynthesis. At night the process stops and some algae and plankton begin to die which actually consumes oxygen. It is highly recommended that an oxygen test kit be purchased if intensive aquaculture is practiced.

These colormetric test kits are available from Chemetrics (1-800-356-3072). The test kit # is K-7512 and sells for $38.00. Refills are available for $19.00 for a 30 tube kit. If you have an unlimited budget, you can purchase a portable electronic dissolved oxygen analyzer from Hach Chemical Co. for about $800. My experience is that the cheap test kit is more than adequate for small aquaculture operations. Other important considerations in the area of oxygen control and aeration are as follows:

1. Purchase a spare aerator. If you have a pond full of fish and your aerator fails, it may take days to get a replacement even if you order express shipment. A significant number of fish could be lost during this period.

2. Have a portable generator for periods when electric power may be lost for extended periods during the hot summer months. This investment could save your fish during extended power outages caused by storms etc.

3. Do not throw organic matter such as hay or grass clippings into the pond. These materials will use oxygen during decomposition and could cause oxygen depletion as well as discolor the water.

4. Be very careful when utilizing aquatic herbicides in ponds. Even is the material which is utilized is safe for fish, oxygen depletion could occur when the dead vegetation begins to decompose. If these materials are utilized, treat only a small portion of the pond and wait a couple of weeks between applications.

Copyright © 2000-2002 D.K.T Company Limited

[Khonwan]

MATERIAL SAFETY DATA SHEET MSDS NO. 010001

GREEN CAL®

Agricultural Gypsum

Green Cal (Ag Gypsum).pdf

[happyjune]

Thankyou