over half the amount of lime into the water as CaO, than would an equal 

 amount of quick lime. 



Itie finer Is the grinding the greater is the solubility. Limestone 

 marl must have 80 percent of the granules under 0.75 nsa,, fine marl should 

 have 80 percent under 0,3 mm. 



(2) Quick line, burned lime, calcium oxide, as long as it is fresh acts strongly 

 caustic, and deadly irtien sufficiently concentrated. In the liming of pond 

 water with an A.C.y. (acid combining value) of more than 2, the pH value 

 often rises to 8.5, and temporarily also over 9, but soon sinks again. In 

 the liming of lime poor waters with an A.C.V. of below 1, the pH value even 

 with small additions rises quickly to 10 and more. But here also it sinks 

 down in very few hours. In soil liming, a deadly pH value of over 10 can 



be reached only by intensive liming of the moist soil. By combining with 

 carbonic acid, quick lime in water quickly changes. Just like in the air, 

 into calcium carbonate. This sinks to the bottom and during the course 

 of one ot two months it is to seine extent changed into dissolved calcium 

 bicarbonate, Ca (HCO^),. By withdrawing carbonic acid from the water, the 

 quick lime can cause the precipitation of dissolved lime already in the water, 

 and lead to lowering the A.C.V. 



Even though caustic lime tends to bind acids and raise the pH rapidly, 

 yet in its application lime enrichment in the water, the increase of amount 

 of lime present, and of the A.C.V., proceeds more slowly than with calcium 

 carbonate. An advantage of caustic lime over calcium carbonate is that for 

 equal final results, qnly half the wei^t needs to be dispersed. 



In the control of parasites, disease producers and brood foes in the 



drained pond and also in the liming of heavy or muddy pond bottoms, and 

 for the precipitation of organic substances in the water, only caustic 

 lime is to be used. Tt£ lunQ} lime is more stable than the ground quick 

 lime and therefore has a greater caustic action. But, it can be used 

 only for preparing milk of lime for small ponds. The finely ground 

 caustic lime must not have been long stored or stored in dan?)ness, or 

 else the absorption of carbon dioxide and water from the air, will make 

 it useless for disinfectant purposes. Uixed limes from burned lime and 

 calcium carbonate in various proportions are also in conmerce, but offer 

 no advantages in pond culture. 



(3) Calcium Cyanamide . Ciis contains 60 to 70 percent of quick lime and 18 



to 22 percent of nitrogen. Is not only caustic but also deadly on account 

 of the liberated cyanamide. (This will disappear though, through gradual 

 decon9)os ition into urea, ammonia and nitre.) Still, the effects of 

 cyanamide persist much longer than the caustic effects of the quick lime, 

 which are usually over after 2 or 3 weeks. 



On the other hand, I have found that the effects of cyanamide are 

 still noticeable months afterwards, especially in winter. This makes 

 the product especially serviceable for the destruction of unusually 

 resistant disease germs. Still greater care than when en^sloying q\iick 

 line must be taken to prevent an outflow from a trout pond, thus treated, 

 into other ponds, stocked with fish. 



Liming is bo conducted, that either the drained pond bottom is limed, or that pond 

 water is limed from a boat, or the inflow water may be limed. In the control of gill rot 

 and the precipitation of organic substances, naturally the water must be limed. Other- 

 wise in parasite control, the bottom of the pond is to be sprinkled, and likewise for 

 bottom inprovement. In some cases the lime is woriced in with the soil pulverizer. In 

 all other cases it is immaterial how the liming is done. In strewing on the bottom or 

 from a boat the distribution must be very thorough. Only finely ground lime must be 

 strewn. No lumps of quick lime must get into the pond. However, in small trout ponds, 

 the bottom can be treated with milk of lime made from Ivmp lime. Bottom liming should 



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