pH goes from 7 to 7.8 in 24 hours

[FishBliss]

My question is about pH and why it would go from 7 (tap) to 7.8 in 24 hours. I've done a water change every night this week to try to keep the pH closer to normal.

I know that aeration can help increase pH by driving off co2. My plants are consuming what other little c02 there is, so is the pH soaring because there is not enough co2?

29 gallon tank has 40 watts total (low).
ammo zero
trite zero
trate 5-10
pH 7.8 (or it might be higher! the test only reads that high)

I've been dosing Florish excel but don't see any improvement in carbon.
Recently added Florish. (would that raise pH?)

I guess I'm looking for clarification on what is out of balance. My tank params have not varied all that much over many months until I added live plants and I seem to have an unstable tank now. I don't want to over-react and make it worse, but it seems I need to change something.

I have my lights on timers -- 2 5-hour photo periods, with siesta for 6 in between. Is that type of schedule a problem? (that's so I can visit my tanks and feed them before and after my very long work day and algae was growing with longer lighting.)

Anyway, advice on co2, o2, pH, lights....help me find balance.

[J double R]

because when tap water is in the pipes and pressurized, it has a certain pH.. then when it has gassed off and is in its normal state, it reverts to its normal pH. doing excessive water changes is not going to fix the issue, and unless your fish are distressed, i wouldnt worry about it. :)

[FishBliss]

That's interesting.

However, until this last week I could usually count on the pH remaining the same all week until I did the normal weekly water change -- or maybe gradually creeping up over many days. Now it jumps up before a day has gone by.

I have cories and I worry about them.

[mattmartindrift]

maybe use a neutral buffer during water changes?

[Sploke]

If its causing large swings, there are a few things you can do -

Put your water change water into a trash barrel or something for a few hours with an airstone prior to adding it to the tank

Not sure how you refill, but if with a hose or python, put a nozzle on the end to make a spray instead of the water pouring in, and keep the nozzle above the water surface.

I have the same issue with my tap water, pH out of the tap is about 7.0-7.2, pH in my tanks is 7.8. I use a hose with a spray nozzle on the end and make sure there is a lot of turbulance when I refill so the water is constantly gassing off as its added. I still get some microbubbles forming in the tank as the remainder of gas comes out of solution, but not nearly as much as I used to.

[FishBliss]

Sploke -- putting my water into a barrel and using an airstone first would do what -- increase the pH so that it matches what's in the tank?

Also, when you say "gassing off" what gas is that? O2?

Just trying to get a handle on the chemistry here.

[Star_Rider]

can you test gH/kH in the tank and the source . Ph drops are common if nothing changes but rise??

[Sploke]

Yes, I have well water and when it is under pressure in the ground, there is a lot of gas in solution, probably mostly oxygen and carbon dioxide. As we know, CO2 in solution will drop your pH. When the water comes out of the tap and is no longer under pressure, the dissolved gasses will come out of solution, sometimes in resulting in a cloud of bubbles that make the water appear almost milky. My plants always look like they're pearling after a water change, which they are not, the bubbles just form on surfaces mostly (think soda in a glass). Anyway, when the CO2 comes out of solution, the pH will rise. So, putting your tap water in a barrel and aerating will allow the gas to come out of solution before going into the tank, so the pH has already stabilized when the water goes into the tank.

[Star_Rider]

fish bliss..do you have well water?

[KarlTh]

Don't worry about it. There's so much paranoia about pH while the fish don't give a [insert word here; I can't believe it just edited out the mildest option I could think of!]

[FishBliss]

Thanks for all the input.

No, I don't have well-water. It's town water and measures 7 out of the tap. It normally stays around 7 in the tank, maybe rising slowly through the week. But recently it seems to jump right up. Since it is different than it had been before it made me curious. Do I need to inject CO2? or just relax? :-) thanks all.

[Star_Rider]

take a deep breath. try to find a gH/kH test kit..these will help you find if there is something amiss in the tank.

I was a little surprised by Karls response. while I agree that pH is not really a big issue..changes in pH may indicate something is wrong..usually a drop in pH may indicate more of a problem.
you may have something in the tank that is leaching and causing a rise in pH.

I know in some areas the Ph may go down after off gassing occurs as municipalities may add buffers that rais the pH to slow down the degredation of pipes in areas with acidic water.

you may also try aerating sample water form the source to see if it is gasses.

the gh/kh test tho will let you know if the buffers are stable so pH would not be a real issue at all.

[KarlTh]

Changes in pH may indicate a problem, but I don't see any reason to think this one does. It looks like a pretty normal change on off-gassing of CO2 in moderately hard water. My point was that the impression is sometimes gained that fish need precise pHs in which to thrive; this is not so. You see people sometimes getting angsty about their pH being 7.4 when they've read in a book that a given fish likes a pH of 7.0, and it just isn't that important.

[Star_Rider]

oh I definitely agree..but when the change is out of the norm. then it might be prudent to investigate.

"However, until this last week I could usually count on the pH remaining the same all week until I did the normal weekly water change -- or maybe gradually creeping up over many days. Now it jumps up before a day has gone by."

this would lead me to believe that there could be another issue.

[FishBliss]

Hi
Aeration made the pH go up up up. I bought a gh/kh kit -- I'll test when I get home and let you know what it says.

[Star_Rider]

could be you'll find your base line ph and go from there..in essence tho..i would probably not change anything.

I suspect your fish will be fine

[FishBliss]

Not sure how to interpret the results of the gh/kh test...
For each thing it took 3 drops to change the color. That means 3 degrees? Is that good? Bad? Neither? Depends?

I found a chart http://www.petfish.net/articles/Aquatic_Plants/Mea_CO2.php that shows the relationship between Kh and pH -- so 3 degrees kh w/ 7.8 pH means extremely low co2. Not sure what to think of that except that my plants may not like that and the BBA that is appearing might be linked to that? sigh.

[KarlTh]

Was it a KH or a GH test? It's a low result, whichever it is. If KH, I wonder if your water company is adding an alkali to the water to stop it going acid and corroding the piping? If so, then the pH would be brought back towards neutral by the pressurised CO2 in the water pipes, then rise as the CO2 was gassed off towards a pH consistent with the alkali added.

[FishBliss]

Two tests, one is gh and one is kh. I'll get the water test results and see what they say. Unless the water company has just started something new I'm still inclined to think there is something IN the tank that has changed.

[Star_Rider]

fish bliss
test both the tank water and the source independent. this will show you if there is a difference.

[FishBliss]

did that....the only difference was in the pH.
I have to say, I don't care for the gh/kh tests. The color changes are not that vivid and it seems sort of iffy.

[OhNo123]

According to my scientist friend, our hands are Basic ( about 7.0 PH ). Has your hand been in your tank for a long time?

[KarlTh]

If the GH and KH are the same in the tank as from the tap, it's not something in the tank, as tank based causes are nearly always something increasing KH, such as soluble limestone rocks. With a low KH like that, your water company is almost certainly artificially raising the pH with an alkali, because otherwise there'd be a serious danger of the water becoming acid and dissolving the pipework.

Easy way to test - fill a cup with tap water, test pH, leave for 48 hours and test again. My hunch is you'll see the same pH rise.

pH 7.0 is neutral, not basic, and hands don't dissolve anyway.

[Star_Rider]

:iagree:

[kimbo3311]

While I can't tell you why exactly your PH changed, I would suggest instead of going out and getting any crazy "pH solution" instead, go out and get some baking soda. when pH is out of whack in aquaculture systems (especially tanks with high stocking load) we throw some baking soda in there every day to treat it. there are specific calculations you can use to figure out the exact amount to throw in to make it 7.0, but really, you shouldn't have to put much more than a tsp or two and it will act like a buffer and keep your tank's pH and hardness within optimal parameters. You don't have to worry about being too exact, and shouldn't have to dose it every day, this would only be necessary if you were growing tilapia at, say 1kg of fish per liter of water.

[FishBliss]

If the GH and KH are the same in the tank as from the tap, it's not something in the tank, as tank based causes are nearly always something increasing KH, such as soluble limestone rocks. With a low KH like that, your water company is almost certainly artificially raising the pH with an alkali, because otherwise there'd be a serious danger of the water becoming acid and dissolving the pipework.

Easy way to test - fill a cup with tap water, test pH, leave for 48 hours and test again. My hunch is you'll see the same pH rise.

pH 7.0 is neutral, not basic, and hands don't dissolve anyway.

i'll test the tap water
good ideas all

[KarlTh]

While I can't tell you why exactly your PH changed, I would suggest instead of going out and getting any crazy "pH solution" instead, go out and get some baking soda. when pH is out of whack in aquaculture systems (especially tanks with high stocking load) we throw some baking soda in there every day to treat it. there are specific calculations you can use to figure out the exact amount to throw in to make it 7.0, but really, you shouldn't have to put much more than a tsp or two and it will act like a buffer and keep your tank's pH and hardness within optimal parameters. You don't have to worry about being too exact, and shouldn't have to dose it every day, this would only be necessary if you were growing tilapia at, say 1kg of fish per liter of water.

Baking soda will always raise the pH; it won't lower it.