LOW PH please help

[yzf450motoxrider]

I have a 125 gallon aquarium set up for 4 months now.
fish: one 9in pbass, one 5in pbass, and one 7in oscar
filtration: one rena xp3, and 9 watt UV sterilizer.
i tested the water the other day
Resaults: 0ppm ammonia, 0ppm nitrite, ? nitate, PH 6.0 or less

so i preformed a 60 % water change and tested again.
water form the tap has a PH of 7.0
Resaults: 0ppm ammonia, 0ppm nitrite, 10ppm ritrate, PH 6.5

so i waited 4 days and tested again
Resaults: 0ppm ammonia, 0ppm nitrite, 20ppm nitrate, PH 6.0 or less!

i did this a few more times and discovered the PH drops .2 in about 24 hours.

Can somebody please help me is the nitrate effecting the PH?
I dont think my tank is heavily stocked.
Is there anything i can do to prevent this?

Thanks in advance for the help!

 

[Bderick67]

Nitrate is not affecting the PH. Do you have large amount of driftwood in your tank?

Test the carbonate hardness of the tap water, this has to do with the amount of buffering capability your tap water has and is different from General hardness.

If you find you have very low levels of carbonate hardness you may have to add a pH buffer to your water.

 

[justonemoretank]

This article is great for understanding the relationship between pH and KH. It also gives a simple salt mix which will help raise KH and keep pH elevated and steady. I use it in all of my tanks. I also give this link at least once a week, because it's just such a great article.

http://www.wetwebmedia.com/FWsubwebindex/fwh2oquality.htm

 

[yzf450motoxrider]

the KH is about 6

 

[Toby_H]

Sometimes when water comes out of the tap it will have gases in it that interact with the PH testing chemicals and alter the readings. Therefore it is a good idea to store water ovenight in an intert container (a drinking glass works fine) and test it the following day. Either add an airstone or stir it occasionally.

This allows the gases to gas out. If this is done and the second day's PH is different than it is right out of the tap, the Ph right out of the tap should be disregarded and considered a flase reading. The second day's PH should be considered the actual PH right out of the tap.

This test should be done in an isolated inert container as the aquarium may have other influencing factors.


Fish waste is by nature acidic and in high enough concentrations can cause PH/KH to drop.


Since you have a KH reading of 6, I suspect that it is more likely you are getting a false reading from your tap due to the presence of gases than it is your tanks PH is dropping. Although since your large water change did bring your PH up to 6.5, it sounds like the Ph could actually be dropping...


Do you have driftwood or plants in the tank? You stated your nitrates were ? In extremely high concentrations they can affect PH. How high are they?

 

[Bderick67]

the KH is about 6

What does your test kit measure in? German degrees or parts per mil(ppm), there is a considerable difference in the two.

 

[knifegill]

Whether your pH drops overnight or the issue is due to tannins or waste, crushed coral gravel will fix it. I have about a handful in the filters of each of my tanks and it tends to stabilize the tank water to around 7.2-7.4pH.

 

[Bderick67]

Whether your pH drops overnight or the issue is due to tannins or waste, crushed coral gravel will fix it. I have about a handful in the filters of each of my tanks and it tends to stabilize the tank water to around 7.2-7.4pH.

Crushed coral may fix it. Or it may not, crushed coral has shown no detectable affect on my tanks.

 

[Toby_H]

Whether your pH drops overnight or the issue is due to tannins or waste, crushed coral gravel will fix it. I have about a handful in the filters of each of my tanks and it tends to stabilize the tank water to around 7.2-7.4pH.

When I lived in Charlotte NC and my water had little to no KH and slightly low PH... Crushed coral in the filters caused the PH to jump up to around 8.0 very quickly.

While I do believe there are situations where a little bit of crushed coral in teh filter will be the answer, I do not believe it is a safe solution to every situation....

 

[Zander_The_RBP]

the water seems like it would be very soft this is whats causing your pH to be so low the reason your pH is different in the tank is as previously stated there are gases in the water that react with the test kit giving false readings

im sure if u left a glass of water out over night with an air stone and then tested it it would test the same as your tank

if this is true having a low pH isnt bad (having an unstable pH is bad) all you have to do is have a big tub to prepare your water over night with an airstone then do your water change therefore there would be no pH swing becuase the pH would be the same