Also, from the linmological side, Ein. Naxamann has rightly placed a lime content of 

 up to 25 mg. CaO per liter in the "oligo" stage, of 25 to 100 mg. CaO in the "meso" stage, 

 and of over 100 mg. CaO per liter in the "poly" stage of the lime range. 



In regard to the effects cf a high calciuci content, my own observations have made me 

 arrive at opinions which greatly differ from those of other authors. 



First of all, I do not agree that a high calcium rate brings about an especially 

 strong alkaline reaction, i.e. raises the pH rate. Rather the opposite is true, as seen 

 from table 7, and also by observation. The pH rate is merely more constant . but the carbon 

 dioxide reserve is much ;::reater . 



I have also found that the supply of aquatics — natural fish food — is not lessened at a 

 CaO-rate of over 100 milligrams, i.e. at an A.C.C. rate of over 3.5. 



In the brooks of Baumberge in T.'estphalia, vdth an A.C.C. of 7, (Beyer quoted it as 6.1), 

 I observed an extraordinarly high rate of productivity. 



Also the blue Alpine lakes — of a reputedly high calcium content, causing lack of plank- 

 ton — are not always so calciferous. The Christies Lake, for instance (in the AHgau), and 

 which appeared to me as extraordinarly clear has — according to Lotz — a pH rate of 2. A and 

 a hardness of 5.8 "German" degrees, which corresponds to a rate of only 59 milligrams CaO 

 per liter. 



1 liave not encountered a pond in my practice — up to now — ^which I would regard as 



too rich in calcium . In my opinion, there are no sterile ponds solely on account of a too 

 high calcium content; at any rate, I do not know of any example of the supposedly noocLous 

 effect of too high an A.C.C. rate. 



Table 8 defines once again the significance of an A.C.C. of varying rates. 



Table 8. 



L c C 



,,„,/•*. Pond-ciiltural significance. 



n HCl/per liter. 



7i"ater strongl;/ sour, unusable for Imtchery purposes; 

 u or negative. adding chalk to the vfater unprofitable in most cases. 



0.1-0.5 cc eq. A.C.C. very low, pH rate mostly below 7. Great danger 



2-S drops. °^ v/ater turning sour and of the pH rate reaching the 



(en. 2.86-1/; mg. ^.cid dan;:er point. Danger of dying off of fishes, pll 



CaO per liter) rate variable, carbon dioxide supply poor, consequently 



water not very productive. 



0.5 to 2 cc eq. pH rate variable, carbon dioxide supply medium high, 



^ to ''O drops. consequently mediocre productivity. Ho danger for the 



(eq. L' to 56 mg. health of fishes, since a natural turning sour of the 



CaO per liter) water is not to be feared. 



2 to 5 cc eq. pH rate varyinr only ver-j slightly, great optimal 



30 to 75 drops. carbon dioxide supply, rater very productive, health 



(eq, 56 to 1X0 mg. of iishes not endangered. 



CaO per liter) 



5 cc eq. Rarely to be found, pH rate verj' constant. An alleged 



75 drops decline in productivity not proven, so far. Health of 



(eq. LiO iig. fishes not endangered. 



CaO per liter) 



57 



