High Tap Water Ph

[Walkerlr]

Hello all
 
I'm new to the fish community. I have kept fish before but not seriously until now. I have some question on options for my tank water. My tap water is much higher than I'd like it to be, 8.4.
 
What would be a good idea to lower ph? for water changes?
can my fish adjust to this?
should i mix tap and bottled water?
 
Like I said, I am fairly new and would like some advice. Thanks!

 

[fluttermoth]

Hi there, welcome to the forum

Whether you need to lower your pH or not depends on a lot of things.

First of all, you need to find out the hardness of your water. Hardness (the amount of dissolved minerals in the water) is actually much more important to fish than pH is. You should be able to find out how hard your water is from your supplier's website

What sorts of fish are you interested in? Some fish can adjust to higher pH levels, and others actually prefer them.

In nature, hard waters have a high pH, while soft waters have a lower value, but in our mains water supplies, this can be adjusted by the water company. You'll need to let your tap water stand for 24 hours before you test the pH, to get a true value, if you haven't done that already.

 

[Akasha72]

hi and 

 
Agreeing with Fluttermoth. A high pH often points to hard water - although as Fluttermoth says, it's best to check. I'm a big advocate for stocking our tanks with fish that like what water we have. 
If it turns out your water is hard (as I suspect it is with a pH as high as that) then look into researching hard water fish - guppies, mollies or even mbuna cichlids if your feeling that way.
 
There are ways to soften the tank water - adding a peat layer as substrate, adding bogwood can help to soften too but then you get into the danger of making it hard work when you need to water change as there will be a discrepancy in tank - tap. Another option would be to use RO water which usually comes with a neutral pH and already treated. 

 

[Byron]

I agree with fluttermoth and Akasha, and I will just add a bit further.  The GH and KH is actually more important than the pH as the effects on a fish's physiology is significant.  Your water authority as fluttermoth said should have the GH and KH data.  The pH is connected, especially to the KH which serves as a "buffer" so you need to know these numbers before any attempt to adjust the pH is attempted, and it may not be anyway.
 
Second, many water companies in areas of softer water will add substances to raise the pH.  Soda ash is commonly added, and lime is another.  The pH rise may be temporary, or may change in the aquarium.
 
This brings me to the testing of tap water.  Always out-gas the CO2 before testing pH.  This is only necessary with fresh tap water, not aquarium water.  The CO2 can vary in tap water and it forms carbonic acid which can lower the pH but only until the CO2 is dissipated.  Shaking the tap water in a small jar very briskly for a few minutes will out-gas the CO2.  This isn't likely to have much impact in your case but it never hurts to do this with tap water.
 
Byron.

 

[TwoTankAmin]

Byron is correct. But he left out half of things. Some water may have too much Co2 in it which lowers the pH. This excess Co2 would not last for long after the water goes into a tank and the result is low pH tap becomes a higher pH when the CO2 is allowed to reach equilibrium. However, it is also possible for tap water to be deficient in CO2. this has the opposite effect, the tap pH will be higher than it will be at equilibrium. So one needs to let CO2 in-gas. For this I prefer to let the tap sit in a  clean glass with an air pump allowed to bubble it for a while. What fosters gas exchanges between water and the atmosphere is surface agitation.
 
I have never used the jar shaking method for out-gassing, but it should work since there likely is room in the jar for the out-gassed CO2. I am not certain there would be enough CO2 in the air space of a jar to do the reverse. I would assume if you only fill the jar 1/4 of the way with the water that would do the trick. But too much water and too little air might be an issue. I am uncertain for sure on this part, but I am 100% certain tap may have too little dissolved CO2 in it as well as too much. I am also certain using an air pump to bubble the class of water will always cause water to reach equilibrium levels.

 

[Byron]

Byron is correct. But he left out half of things. Some water may have too much Co2 in it which lowers the pH. This excess Co2 would not last for long after the water goes into a tank and the result is low pH tap becomes a higher pH when the CO2 is allowed to reach equilibrium. However, it is also possible for tap water to be deficient in CO2. this has the opposite effect, the tap pH will be higher than it will be at equilibrium. So one needs to let CO2 in-gas. For this I prefer to let the tap sit in a  clean glass with an air pump allowed to bubble it for a while. What fosters gas exchanges between water and the atmosphere is surface agitation.
 
I have never used the jar shaking method for out-gassing, but it should work since there likely is room in the jar for the out-gassed CO2. I am not certain there would be enough CO2 in the air space of a jar to do the reverse. I would assume if you only fill the jar 1/4 of the way with the water that would do the trick. But too much water and too little air might be an issue. I am uncertain for sure on this part, but I am 100% certain tap may have too little dissolved CO2 in it as well as too much. I am also certain using an air pump to bubble the class of water will always cause water to reach equilibrium levels.

 
The opposite reaction is something I don't believe I have ever come across, so thanks TTA.  Only shows how we continually learn.

 

[TwoTankAmin]

Acid water is bad for pipes and facilitates corrosion. As a result many treatment plants use various means to raise the pH. There are a a number of ways to do this. Hopefully, by the time the water comes out of one's tap a lot of this has dissipated, but it may not all be gone. The higher the pH of water, the less CO2 it holds. But it is not all that common to see water from the tap whose pH drops, it can happen but it is not common as the reverse. It would require the one's water company needs to do things differently because of their source water.
 
As the pH crosses over 8.4 and has the needed buffering capacity, it will hold very little CO2. If that capacity is not natural but is added by water companies, such things may be dissipated once the water is out of the supply system a while. For example:
"If an excess of lime was used to precipitate magnesium ions in the water (Equation 4), some unused hydroxide (OH-) ions will remain in the water after the calcium is precipitated, resulting in a high (or basic) pH.  If necessary, the pH can be lowered by bubbling carbon dioxide gas through the water." (http/www.chemistry.wustl.edu/~edudev/LabTutorials/Water/PublicWaterSupply/PublicWaterSupply.html)
 
You would effectively be bubbling some co2 though the water whether shaking or bubbling with an air pump.

 

[Walkerlr]

Thank you for the replies!
My test kit said I have really soft water but high ph and alkalinity.

 

[Byron]

Thank you for the replies!
My test kit said I have really soft water but high ph and alkalinity.

 
Confirm the test results with the water people.  Most have a website with water data, or if not you can call them and they should be able to tell you the probable GH, KH and pH.  You will also see in the data if they add substances.
 
High pH with a very low GH/KH is possible, I have that.  I'm puzzled by low GH and high KH, but I'm not a chemist.  But before guessing, let's get the numbers confirmed.
 
Byron.