Quick PH Question

platytetrafan

platytetrafan

AC Members
Jan 20, 2007
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NY
Ok my 36g freshwater tank has been set up for quite some time everything is going well. My question is about PH. When I first started my ph was between 7.2-7.6 my local water tests 7.0 on the nose. LFS manager who is very knowledgeable about fish told me to keep a coral skeleton in the tank to help buffer the water. The water stayed about 7.0-7.2 for a while and the fish are doing fine. Yesterday I did a ph test and the ph was 6.0 the fish are fine today was PWC day after the change the water was between 6.4-6.6. All other parameter are normal. My question is do I leave the PH alone see my sig with my fish variety most enjoy a lower ph the platies and rainbows have acclimated to the lower ph not sure if I should mess with water adding ph up or not. Just need some advise thanks :).:feedback:
 
The pH scale is logrithmic, with 7.0 measuring an equal balance of OH- and H+ ions in the water, so if you have water that is in this range on the scale between 6.0 and 8.0, you will see some changes because even slight changes in ion composition will give a visible reading on the test kit, but the overall change in the number of ions present in the water is very small when you go from a pH of 7.0 to 6.0. However, since the scale is logrithmic, the change from 6.0 to 5.0 represents a change in ion number ten times greater than the change experienced between 7.0 and 6.0. In summary, I wouldn't worry until your pH dropped into the mid 5's, at which point you might consider adding baking soda to the tank. Do you know the GH or KH of your water? If the knowledgeable employee is recommending coral for your tank, I am assuming that you have soft water that might need a little hardness that the baking soda could also add.
 
you should test your kH and gH the test kit will help you find out if the water is missing any buffers.

if you find the kH low you may also consider adding mineral salts aka buffers

while baking soda may help the kH some fish need the buffers in the water. others don't.

if your pH is fluctuating and you are not using CO2 injection..I would suspect you may be short in your kH readings.

btw acidic pH may wipe out your bacterial colony. especially if it drops below 6.
 
However, since the scale is logrithmic, the change from 6.0 to 5.0 represents a change in ion number ten times greater than the change experienced between 7.0 and 6.0.
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actually, the change in the ratio of OH to H ions would be the same for either 5 to 6 or 6 to 7.

its a 10 times change.

but a change from 5 to 7 is 10*10 = 100 times change.

which is major :)
 
hmmmm well I have the API test strips would those do to test the kh and Gh? The fish are all doing fine. The rainbows are australian and I have one bosemani. If strips are ok I will test the water tomorrow night and post the readings. For now will not add anything to the tank water.
 
12 Volt Man said:
actually, the change in the ratio of OH to H ions would be the same for either 5 to 6 or 6 to 7.

its a 10 times change.

but a change from 5 to 7 is 10*10 = 100 times change.

which is major :)
Click to expand...

A one point change on the pH scale is actually a 10 times change in the concentration of H+ ions, and for every 10 times increase in H+ ions, there is a 10 times decrease in OH- ions, but don't worry about that right now. For now, we'll just deal with the H+ ions which is what pH is truly measuring. Because one point on the scale represents a ten fold change, it's not linear. Have you ever seen the TV show: "The Power of Ten"? The first question is worth $1,000, the second is worth $10,000, the third is worth $100,000, the fourth is worth $1,000,000, and the fifth is worth $10,000,000. While each question is worth ten times as much as the last, the absolute difference between the first and second questions is only $9,000 while the absolute difference between the second and third questions is $90,000. Meanwhile the difference between the first and third questions is only 10% higher at $99,000. And pH works the same way, when you go from a pH of 7.0 to a pH of 5.0, about 90% of that difference (the vast majority of the 100 fold difference) is accounted for just in the one point change from 6.0 to 5.0. Put another way, a pH change from 7.0 to 6.0 measures the same absolute change in H+ ions as a pH change from 6.0 to 5.9, and only half the change experienced during a pH change from 6.0 to 5.8.
 
A one point change on the pH scale is actually a 10 times change in the concentration of H+ ions, and for every 10 times increase in H+ ions, there is a 10 times decrease in OH- ions, but don't worry about that right now. For now, we'll just deal with the H+ ions which is what pH is truly measuring. Because one point on the scale represents a ten fold change, it's not linear. Have you ever seen the TV show: "The Power of Ten"? The first question is worth $1,000, the second is worth $10,000, the third is worth $100,000, the fourth is worth $1,000,000, and the fifth is worth $10,000,000. While each question is worth ten times as much as the last, the absolute difference between the first and second questions is only $9,000 while the absolute difference between the second and third questions is $90,000. Meanwhile the difference between the first and third questions is only 10% higher at $99,000. And pH works the same way, when you go from a pH of 7.0 to a pH of 5.0, about 90% of that difference (the vast majority of the 100 fold difference) is accounted for just in the one point change from 6.0 to 5.0. Put another way, a pH change from 7.0 to 6.0 measures the same absolute change in H+ ions as a pH change from 6.0 to 5.9, and only half the change experienced during a pH change from 6.0 to 5.8.
Click to expand...

a pH change from 7.0 to 6.0 represents a 10 times decrease in hydronium ion concentration.

a change from 6.0 to 5.9 is a change of:

10^-6.0 - 10^-5.9 = 0.74..times decrease, which is a lot less.

(since H+ concentration is the antilog of the (-pH) = 10^-pH.

I wish I could show exponents on here! :)

remember:

pH is the negative logarithm of the hydronium(H3O+) ion concentration. chemists often shorten this notation to simply H+.

there is also a pOH as well, which is the opposite of the pH scale..

pH chemistry can be quite complex...and it brings back evil memories of my school days..:mad2:
 
LOL ok I remember this from chemistry. I am an RN I did test the water but only had API test strips in the house and not sure if it is reliable or not but the KH result was 60 which the bottle says is fine and the GH result was 0 so in plain english what does this mean now since the fish are fine LOL ;).
 
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