| awww now i gotta use my head..hungover.
buffering capacity is sposed to be directly related to water alkalinity. which is not the same as highly alkaline soil or water (its not a pH measure).
i think thats where a lot of people are confused.
its a measure of the calicum carbonate and calcium bicarbonates, umm im thinking its more than just calcium carbonates actually as in magnesium carbonates also, these also contribute to the buffering bank but i think the basic test involves the carbonate hardness from calcium only but i may have that wrong in that the test may test for both mag and calc.
it goes something like this.
carbonate hardness test kit is a measure in ppm, it comes in a simple test kit, it tests for carbonate and bicarbonate and you are sposed to be able to use this as your test to see if you need to add lime, you add the drops into the 5ml vial and once the sample changes from blue to yellow, you count your drops used to change the colour and multiply it by ten.
for example you may come up with 3 drops times by ten and then you know you have 30mg per litre present. they say that under 20mg/l and you would have rather poor buffering and subsequently poor crops.. but between 40 and 80 is good enough. if for some reason you ocme across really high presence above 200mg/l then your waters/soils not so suitable either. dunno what they do if that happens..
however i think it would be of concern if you had waters/soils foir example that had a lot of magnesium making up your total hardness.. ie in some land forms you mayt have high amonts of magnesium which would also act as buffer. i think that the carbonate hardness only shows the calcium carbonate presence and that the total hardness test shows both calcium and magnesium and some other salts also. so i guess you would do both tests to work out what salts where making the difference.
as for how it works.. its the presence or amount of bicarbonate ions (dont blame me if ive got this wrong cause im no chemist)
but how i undrestand it is that the bicarbonate grab onto carbonic acids that are there in the water and so what this does is stop the pH going way low.
think that carbon dioxide would lower pH as an acid and that these carbonates hold them, bind with them and stop them causing so much effect to the parameter of pH.
if theres a lot of carbon dioxide around in the morning and then its used by a bloom (producing oxygen) then the pH rises casue theres no carbon-acids present.
obviously its not real good to have too much acids or carbon dioxide around..
anyone ever breathed in pure co2? the stuff is retched.. its like anti life.. and its funny that we put it in our soda drink..pure o2 on the other hand is clean and tastes like life.
as for your kh tests, those german ones i have absolutley no idea if theres any difference..but this has served me ok. cichlid growers run them up real high to mimic the lakes..and talk of kH but i think it be the same.
so if you have a night with no earation and maybe a lot of cloud the arvo before stopping any photosynthesis then your fish and bloom respires a lot then theres heaps of carbon dioxide around, if theres not much cabonate ions around then what happens is that there will be a lot of free roaming carbon dioxide that will lower pH.
the addition of lime will inittially raise the pH but thats worth it for the buffering ability now present.
still even with well buffered waters and trying to create big blooms full of food you can get high pH. too high for stocking. at thios tiome you can wait till it settles back, if the fish goes in there when its real high its worse than when it goes in at a suitable pH say around 8.5 give or take one.. and then rises throughout the day. thats a stress stocking if you wack em in when its high.
better to stock when the pH is lower in the morning.
one thing to remember is that with big water exchanges you can flush away your lime and therefor buffering capacity.
that is how thew water buffers against pH swings |