Interesting question. I have a couple of ideas (which may be totally useless).

The idea of off-gassing (basically "evaporating" the chlorine into the atmosphere) works with chlorine, but not with chloramine, so the previous change in pH over time is consistent with chlorine (although in the wrong direction - chlorine will cause you to start with a lower pH and it would rise to 7'ish, not the other way around). So, I'm not really sure what could be causing the pH to be that elevated. Water companies try to keep it around 7.5 to prevent corrosion to the pipe system.

This website suggests that chloramines can be removed by sunlight or aeration - did your previous off-gassing sit in the sun or were aerated somehow??

The idea that it's a testing error is also possible. In medicine, the measurement of blood sugar is affected by various other biochemicals. Is there something in the water that causes the pH to be high and then is slowly degraded/off-gassed/consumed and pH returns to neutral? Completely possible. But it would be the fact that your water company may have changed from chlorine to chloramine, which could explain why your latest pH didn't budge until you added Prime.

Basically, I believe that your theory of treatment with Prime allows the pH to become neutral; what's confusing to me is that the pH should be acidic due to chlorine and over time increase to neutral; the alternative is that the pH was adjusted high by some other chemical from the water treatment companies - do you have lead pipes?? Just kidding.

Hope this wasn't completely useless.

 

Hope this wasn't completely useless.

not at all. some interesting thoughts.
we've had chloramines in our water for several years. typically i treat the water at the beginning of the aging process but didn't this time. i've aerated in the past as well but since the water was usually treated i wouldn't know if this made a difference.

however in this batch i had 2 buckets that were being aerated while the others were not. none of the buckets, aerated or not, dropped in pH until after they were treated with Prime. i won't be able to determine if they would have eventually dropped on their own without being treated as i've gone ahead and conditioned all of the samples with Prime.

it is very curious that the pH is moving down instead of up as you mentioned it should. hopefully someone can shed more light on this mystery.

 

Just wondering if perhaps Prime has an effect on things other than chlorine or chloramine. If you tried using another more generic water conditioner that only affects these two things and doesn't claim to detoxify heavy metals, you could narrow it down.

 

Seachem Prime (and most all conditioners on the market) contain EDTA to chelate chlorine, chloramine and heavy metals. Basically, it gloms onto these molecules, making them unable to interact with living organisms and "neutralizes" them. I believe EDTA has become the standard in conditioners in today's market.

 

Hm. Well from what I understand that wouldn't lower pH. I wonder if there's a such thing as a dissolved gas that makes the water alkaline?

 

I'm all out of ideas - other than possibly some bacterial process going on in the background.

Silas, btw, after adding Prime, there's no need to aerate or let the water sit in order to off-gas - Prime does it for you. However, you're still left with the pH issues. Sorry, dude.

 

You could try adding Prime to some other water and see if it goes acidic too. Maybe something is wrong with your bottle of Prime. What is your KH?

 

my KH is 6 °dKH or 107.4 ppm.

i'll probably get a different pH test kit and try again.

 

Another thing you could try is treating the water as normal, and then putting it in an airtight container with no air. Take another bottle and do the same thing, but don't treat it. Do the same thing with two containers of water that are open to air. (Make sure all containers are inert, like plastic) If after 24 hours the water treated with Prime and sealed has dropped pH, but the other one hasn't, it has to be the Prime adding acids to the water somehow. If both sealed bottles have dropped, there's some kind of reaction taking place in the water. If neither bottle has dropped, but the ones open to air drop, it's something offgassing.

 

Prime doesn't lower pH.
That's interesting tho. With your KH, I'd expect pH to be more like it runs in your tank.
I wonder if they're using soda ash to raise pH (to keep pipes from leaching metals into the water).

 

Once I had a water conditioner that somehow went bad, and actually turned into ammonia. I couldn't figure out why I was getting ammonia readings no matter how often I changed the water. It wasn't a chloramine thing either, the more water conditioner I added, the higher the ammonia would go. Every other water conditioner I've had since works great. I think the bottle somehow went bad, so I don't assume anything is safe anymore when presented with conflicting evidence.

 

Was it Prime? It will give a false positive the more you use unless you use seachem's own test. I had the same problem when I had my water tested at a LFS and he ended up selling me zeolite. My tank was brackish then and when I looked it up and realized that salt would actually cause the adsorbed ammonia to be released, I didn't use it.

The problem was that I was using too much Prime during water changes. I thought it was easier to use a capful than to measure out enough for a 5 gallon bucket, which would have been 1/10 of a capful. Using that much can bind free O2 and give fish the same symptoms as O2 deficiency or CO2 poisoning.

 

i wrote the local water department chemist for an explanation. i'll give you a rundown of what i learned.

our water averages a pH of 9.3. it is treated with lime which raises it to 10.5. it is then treated with carbon dioxide which lowers the pH to 9.3. she didn't tell me that they also treat it with soda ash which i learned from their website.

when the water reaches the home and it is exposed to air the CO2 in the environment dissolves into the water which lowers the pH.

i was a little confused as i thought the extra CO2 they added would then off-gas in the home and raise the pH instead of lowering it but she explained it this way:

The CO2 that is fed after the softening process turns the hydroxide into carbonate and the carbonate into bicarbonate. There is not an excess of CO2 in the water. The CO2 is used to convert the higher pH forms in the carbonate buffering system into that of the lower pH forms of the carbonate buffering system. (hydroxide (highest pH), carbonate, bicarbonate and carbon dioxide (to the lowest pH form).

Once you draw a glass of water and expose it to air, the CO2 in the air will dissolve in the water and lower the pH. That is why the pH lowers.

so there you have it. even though i may not fully understand it.

 

i wrote the local water department chemist for an explanation. i'll give you a rundown of what i learned.

our water averages a pH of 9.3. it is treated with lime which raises it to 10.5. it is then treated with carbon dioxide which lowers the pH to 9.3. she didn't tell me that they also treat it with soda ash which i learned from their website.

when the water reaches the home and it is exposed to air the CO2 in the environment dissolves into the water which lowers the pH.

i was a little confused as i thought the extra CO2 they added would then off-gas in the home and raise the pH instead of lowering it but she explained it this way:

so there you have it. even though i may not fully understand it.

That doesn't make any sense to me either. Why treat with lime and then CO2? Then again to treat with soda ash? It seems a triple redundancy to me. Especially since it doesn't seem that your water ever has a low pH to begin with.

 

according to their website:

The disinfected water then flows into the coagulation, flocculation and softening basins where lime and alum are added. Lime reacts with various dissolved minerals to form primarily two insoluble precipitates: calcium carbonate and magnesium hydroxide.

after some more softening and clarification...

After the primary clarification basin, carbon dioxide is bubbled in to stabilize and lower the pH of softened water. Controlled application of soda ash and phosphate is also added at the primary recarbonation basin to increase the alkalinity level and provide corrosion control.

the way i understand it lime is used to grab onto water hardening minerals so that they're easier to remove. it's all very up and down. first they raise the pH with lime, lower it with CO2 and then raise it again with soda ash? and then in the end it comes back down when CO2 in the consumer's air gets back in it. i never was any good at chemisty.

 

according to their website:

after some more softening and clarification...

the way i understand it lime is used to grab onto water hardening minerals so that they're easier to remove. it's all very up and down. first they raise the pH with lime, lower it with CO2 and then raise it again with soda ash? and then in the end it comes back down when CO2 in the consumer's air gets back in it. i never was any good at chemisty.

I'm not a chemist but it still makes no sense to me. Lime HARDENS water. CO2 lowers pH, which would actually help in leaching metals from pipes, which is undesirable. Sodium and Potassium are what's used to soften hard water and replace Ca and Mg but will not lower the pH. They will lower the GH but not KH.

Is there a chemist who could explain, in laymen's terms the addition and requirement of CO2 to Silas's water....or the whole spiel?

 

Silas K,

This is still confusing the heck out of me. What is the location of your water source? No offense to where you are from. Can you post a link to the quotes? I'd like not to believe that they are just spewing off some nonsensical excuses.

I may just be stupid...sorry,

 

Soda ash is sodium carbonate... sodium will not alter pH, but the addition of carbonates will raise pH if you're starting out with an acidic pH as it will neutralize the acid to a certain extent. Similar effect as baking soda (sodium bicarbonate). And yes it will add carbonates, or buffers.