A Ph Of 7.6

[Crazy fishes]

I have to apologise because I got the carbonate and bicarbonate pH the wrong way round. Carbonate does produce higher pH i.e 12-13 whereas bicarbonate has the lower pH of around 8. I got into the flow of writing and ignored what I was actually ...... well ...writing . The rest is as intended to be written, apologises once more.
Ski, I know that you were right it was CO2 but the CO2 was low. Have you ever come across the equation:

CO2 +H2O = H2CO3 = H+ + HCO3-
CO2 = carbon dioxide, H2O = water, H2CO3 = carbonic acid, H+ =hydrogen ion and HCO3- = bicarbonate/ hydrogen carbonate
The = is to signify the reaction is freely reversibly. When seeing patients that are severely unwell this equation is THE equation to remember because it explains the acidosis or alkalosis that patient's experience (sorry more medical analogues). This is nature's primary buffering system it has been conserved and is present throughout biological and chemical systems. The reason for the CO2 being low whilst large amounts were dissolved is because my HCO3- was very low. The above equation is affected by pH or more correctly the H+ concentration. We have to remember that my pH (7.6) was still classifed as alkalotic which means the pH was pushing the reaction as it is written left to right. The CO2 would have been consumed to produce bicarbonate which was still low because it was meeting H+ immediaitely and bouncing back to carbonic acid therefore not replacing the loss. I think the essence is this the molar quantities which I believe you were eluding to were out of 'Whack' and the above equation found an equilbrium at a pH much too low for what we would like in our marine aquariums.
MY TEST KIT IS USELESS I.E. FAULTY
Kalkwasser is just chalk water, I believe in German. Chalk water is calcium carbonate and that is what I am now dosing my tank with. I don't have room for a refugium or I would start one. As I have said before in my tiny bedroom I have a Rio 180 + cabinet, a Rekord 96 and my 24g nano cube + cabinet and 2x 25l water containers and my desk and beds and a a library on the walls which leaves just enough floor space to get in and out of the room.


Kindest regards guys and girls.

 

[SkiFletch]

Kalkwasser may stand for chalk water (I don't speak German ) but it is not calcium carbonate. CaCO3 salts are extremely insoluble in marine aquaria. Coral skeleton, live rock, and many other things in our tanks are actually Calcium Carbonate. Were it easily soluble in seawater, there would be no live rock, stony corals, or calcerous algae in the oceans

Kalkwasser also goes by another name we english-speaking people are more familiar with: limewater. It is Calcium Hydroxide which obviously has an exceptionally alkaline (high) pH. As it dissociates in water it helps release/create Calcium and Bicarbonate through a series of reactions with water and CO2. Kalkwasser is a great way to dose balanced calcium and carbonate while keeping pH elevated. However one can easily over-do it and spike their pH to unsafe levels, so it is often dripped into the tank.

You are absoloutely right with your equation but you are misisng the last step which occurs in seawater with nearly saturated carbonate conditions (not seen in the human body):

H+ + HCO3- = 2H+ + CO3-

Thus making high CO2 lead to elevated H+ and lowered pH Hope this helps you out Crazy Fishes, or some other members reading this with the same question. If you want further reading on the subject, might I suggest geting it from someone with a PhD in Chemistry; Low pH, Causes and Cures by Dr. Randy Holmes-Farley

Hope that helps

 

[BigC]

Hi,
My pH is a tad on the low side at present, Red Sea Buff as I understand from the instructions is to increase the Alk. The instructions state that if your pH is on the low side then perform Daily 10% waterchanges until it comes into line. Which is what I'm doing as we speak. The water when newly mixed (12 ltr) is comming in at 8.4 and a temp of 80'f and SG 1.026.
The pH of the water in the tank when performing the changes is gradually rising.
Readings taken at the same time each day.
Saturday 7.8
Sunday 8.0
Monday 8.2
Trying to achieve 8.2 - 8.4 . So for the main part it seems to be working. The proof of the pudding so to speak will be when I revert back to weekly waterchanges. Will it remain stable, we'll have to wait and see.
Regards
BigC