Aragonite supposedly keeps the PH around 8.2 or so. So, why add buffer if PH stays?

[hairtrigger]

I have an all aragonite sandbed. It said on the bag that it keeps the PH around 8.2 or so. My PH always seems to be around that when I test it. And when I add buffer, my corals seem to shrink up a little bit. PH raises up to around 8.4 or so. So would you recommend avoiding buffers?
I didn't touch the tank for two weeks one time. Best I'd ever seen the corals.
Should I just add calcium instead? Right now I use Kent Tech CB parts A and B. (calcium and buffer combined) Seems almost detrimental.

 

[jarre]

If your PH is staying steady without it then I wouldn't add any. Personally all I add is Alk buffer because of what happens if I don't! I haven't added calcium in two months and still have a reading right at 490-500 with a PH of 8.2 and an Alk of 10.2. I'm beginning to believe that less is more.
Where in Atlanta are you located?

 

[hairtrigger]

Yeah I agree with you. I am still trying to figure out the chemicals... or lack there of... in my tank. It has been up and running as a reef for about a month now. Previously it was a FOWLR. My corals haven't really FULLY opened so I am thinking it has something to do with chemicals. My water quality is great so, I am just weeding out the problems now.
I am in Buckhead/ Vinings in Atlanta. Right near the Governor's place. What about yourself?

 

[hairtrigger]

PS--- what happens if you don't add yer alk buffer?

 

[jarre]

My Alk drops fairly fast so I keep it up with the buffer. When the Alk goes so does the corals!

 

[hairtrigger]

Ok... stupid question here. Maybe anyways. Before I ask it... keep in mind... I just turned my old FOWLR into a reef. I tried a reef once and it failed. So, I resorted to FO and have done that for many years. I didn't have to get very technical on that. So, now I am up to a CHALLENGE. And I am getting it.
PH and Alkalinity... are they two different things???????
I have been under the impression PH Buffer is the same as Alkalinity Buffer and that PH and Alkalinity are the same. Because PH can be alkaline or not. Ugh.
Eg... Kent Tech CB Parts and B.
Ok.. so before I get crucified for askin that one... please answer kindly.

 

[mlm]

According to one of the sharks I think Broomer it does not help unless the ph gets so low it would be detrimental to the tank.

 

[broomer5]

Yes HairTrigger
pH and Alkalinity are two different things.
pH is simply the number of hydrogen ions in the water.
Hydrogen ions are basically a proton H+
It's sister is the OH- hydroxyl ion
Pure water is H2O
That's (1) H+ hooked to (1) OH-
Otherwise written as H-O-H
Neutral pure water has an equal amount of H+ ions as it does OH- ions
Their numbers are the same - and their numbers are balanced.
There is no more H+ as there are OH- ions
The water is considered to be neutral.
This neutral water is given the pH value of 7.00
The pH scale goes from 0 to 7 to 14
Anything lower than 7 is considered acidic.
Anthing higher than 7 is considered basic ( alkaline )
Our saltwater is around 8.2 so it's somwhat basic ( alkaline )
The pH scale is not linear - it's logarithmic
What this means is that for each ph step you measure - the number of H+ ions is increased or decreased by a factor of 10.
pH 7.00 has equal numbers of H+ as it does OH-
pH 6.00 has 10 times the number of H+ as does 7.00 liquids.
pH 5.00 has 100 times the number of H+ as does 7.00 liquids ~ and so on down the scale.
pH 8.00 has 10 times fewer H+ ions as does 7.00 liquids.
pH 9.00 has 100 times fewer H+ ions as does 7.00 liquids ~ and so on up the scale.
pH = number of H+ ions
Acids contain a lot of H+ ions
Bases contain a lot of OH- ions
When we buffer our tankwater - we add chemicals that are called salts, or buffer additives.
They contain carbonates, bicarbonates and some other compounds that when mixed with water - will neutralize the acids - causing the pH to rise or be maintained.
Acids pull the pH down cause they contain H+ ions.
Buffers neutralize these H+ ions and keep the pH up.
If you have purewater where the H+ and OH- are equal and you drop in a few drops of an acid - the pH will drop.
Let's say you add JUST ENOUGH buffer to totally neutralize the acid - but no more than just is enough to do the job.
The acid is neutralized now.
Now you add another few drops of acid.
Again the pH drops - and you would need to add a little more buffer to neutralize this acid.
Obviously - no one is going to stand at their tank - and take pH measurements all day and all night long - and then add "just enough" buffer to neutralize the acids.
This is where alkalinity comes in.
Alkalinity is a "reserve" of buffer compounds that are built up and hopefully kept up to a level that prevents the acids from dropping the pH.
If you have adaquate alkalinity maintained - as an acid molecule is created by natural processes - the alkalinity reserve says" hey there's an acid moelcule" ! I better donate some of me to neutralize that acid.
The alkalinity does this all the time.
When an acid molecule shows up - the alkalinity steps in and neutralizes it. Each time it does this - it loses a little bit of itself.
Eventually - as lots of acids come around - the alkalinity becomes weaker and weaker - cause it keeps giving up a little of itself to keep up neutralizing all the acids.
In our tanks - the pH is the measurement of acid.
We don't want these acids to float around in the tankwater.
Alkalinity preserves the pH, or protects the pH from dropping by jumping in when necessary to get rid of the acid.
So pH and alkalinity are related ~ but not the same.
If for some reason you allow the alkalinity to drop down really bad - when an acid comes around - the alk is so low that it can't do it's job anymore.
Then the acids WIN and the pH drops fast.
Keeping your alkalinity around 7-10 dKH keeps the tankwater strong. The acids won't win the battle because there's enough alkalinity to keep the acid neutralizing game going.
Lastly:
pH buffers designed for marine tanks affect the pH right away.
They contain compounds that will attack the acids fast.
If overdosed - often they will drive the pH up too far above 8.3
Alkalinity buffers normally do not affect the pH real fast.
They are builder compounds that build up the alkalinty - without haveing a direct FAST affect on the pH.
Normally - a combination of both marine pH buffers and alkalinity buffers are required to give the tankwater a quick boost or rise in pH AND maintain the alkalinty by adding to it's strength.
Marine pH buffers work fast.
Marine alkalinity buffers work slower.
There are a ton of other things going on in the tankwater at the same time - besides just this acid balancing act that the buffers play.
Calcium
Magnesium
CO2 gas
and a host of other chemical reactions are taking place too.
In the ocean - all of this is taken care of naturally. Bicarbonates and carbonates and acids are all being created by natural processes and the contribution of atmospheric CO2 gas.
Everything is normally kept in balance in the sea - because of the huge volume of saltwater, minerals, gasses and so on.
In our little glass tanks though - we as caretakers have to step in and add or subtract things to keep everything balanced.
Otherwise - the tank will eventually crash.
In our hobby, espeically with a reef tank - understanding the pH, alkalinity and calcium relationship can be a little tricky.
But it's not impossible to understand.

 

[hairtrigger]

Broomer... yes... a little tricky to understand. But you should have been a teacher. Because all that info was a Godsend. I am going to do some research on it now to try and diagnose my problem better.
Man, thanks for that response. I can tell you put a lot of time and effort into it . Just want to say: Much appreciated. Thanks. You've helped me learn a lot on here so far.

 

[jonthefb]

great job as usual broomer, demystifying the pH/alk/ca relationship!
jon

 

[broomer5]

Thanks guys
HairTrigger
Back to the original question way up top ^
If you're pH is always around 8.2 - you got it made in the shade.
Most folks would love to have that reading.
If it's at 8.2 - no need to add buffers or alkalinity builders.
But ... still a need to measure/monitor the pH.
If you're moving towards a reef tank - I'd suggest getting a test kit for pH, alkalinity and calcium.
Use them - they will take the guesswork out of much of this stuff.
Then - you can make a better decision on what to add and when.
Especially when talking dose rates and what these doses DO to the tankwater tests.

 

[hairtrigger]

Sweet broomer. I am going to pick one up tomorrow. All I have in there now is fish, a green bubble, a pearl bubble, an open green brain, a ricordia rock, and a mixed mushroom rock.
The two bubbles haven't ever opened up fully except for two weeks when I didn't touch the tank at all. Then I dosed it again with Kent CB, A and B,
strontium and molybdenum, and iodine. They shrunk back up. I haven't added anything but the CB and they opened up a little bit. My PH seems too high after adding it so I am going to stop. Maybe stick with just calcium. What about iodine... necessary additive?