By top up I mean top up water. And buffer, well water from a well or often city water has calcium carbonate (lime) in it and this is a buffer that will dissolve in water when the pH drops below a certain point, like 7.6 or 8.2 depending on the particular kind of lime. Anyway, say you have a barrel full of hard well water, you may need to add acid to it more than once to "counteract" all the "hadness" or buffer suspended in the water. For instance, when you first add acid to the water the pH will come down below the "buffer point" and the buffer will then bring the pH back up to the buffer pH at which point it stops dissolving so to speak so you then add more acid and the buffer will dissolve more until the pH comes back up and it stops. You may need to do this until the pH comes down below the buffer point and stays there proving to you that all the buffer has been used up.
Now once you get to know your source water after doing this a few times (keeping in mind that there may be seasonal fluctuations in the hardness of well water or the additives a city may put in the tap water) you will probably have kept track of how much acid was needed overall to counteract the hardness of the water and get the pH down so that in the future you will be able to prep a barrel full of top up water by adding that amount of acid once and then waiting a few days and then double checking the pH and all that before using the water in the system.
And to further confuse you, I'll add that once a system is mature and the pH is coming down naturally, you might not want to totally counteract all the buffer in your source water since you may need something to help bring the pH in your system back up. You could probably simply do this with the calcium hydroxide and potassium hydroxide that are commonly recommended or some people will use calcium carbonate (lime) and potassium bicarbonate to do this but in my situation I've found that I can adjust my system pH by choosing between using my well water to bring pH up and if the system doesn't need the pH brought up I'll use rain water when I can.
Totally confused yet?
Basically the buffer is just suspended tiny bits of stuff like calcium carbonate or lime in the water and counteracting it is dissolving it all away using acid until it is no longer able to bring the pH back up.
That makes a lot of sense. Thanks TCL!
Wow, I did not see your post, look at mine below.
I was told drift wood or peat moss.
Jim Logios said:
I just started a system, and the ph is up around 8. I spoke to a woman I work with who heads up the "Trout In The Classroom" program at the school I work at. I asked her what she uses to lower the ph, and her answer was "sticks". Sticks I asked... what kind of sticks? The wooden kind she replied... a few small dried branches from a hardwood tree such as Oak or Hickory. Apparently, tannic acid is naturally in them, which makes for a cheap (if not free) solution.
Anyone ever try this?