Different 'ph' Readings From Same Tank - Is This Possible?

[jts123]

Hi all

I am currently almost 2 weeks into a 'Fishless Cycle' and all appears to be going fine (mostly).

Now, I do know that unless there is a suspision that the PH has fell dramatically causing a 'slow down' or 'crash', there is perhaps NO need to take or worry about PH tests at all during the 'cycle' period. (Due to high possibilty of mis-leading results caused by the cycle etc..) But I just came to a stage where I fealt I would just like to take a reading and make sure all was well.

So, using the API Liquid test kit I did a 'normal' PH test and that indicated a reading of: 7.6 (or maybe just a little higher, due to the colour shown). With this in mind I then decided to do a 'HIGH PH' test and that showed a colour reading of: 8.0 (or very close).

This has puzzled me slighty as I would have thought the fact that even the 'HIGH PH' test should be capable of showing a result of: 7.6, which is the highest achievable in a 'NORMAL PH' test, but the two seperate tests show a slighty different result?


For a more in-depth look at my 'cycle log' please take a look here: http/www.fishforums.net/index.php?/topic/379179-60-litre-fishless-cycle-log/page__gopid__3175622


Can anyone offer any feasible info as to why my differing results are being shown?

Cheers,

John.

 

[This Old Spouse]

It sounds like your pH is closer to 8.0. The normal pH test only goes to 7.6, so it's impossible to tell from THAT test what your pH really reads.

 

[jts123]

Hmmm, thanks for the speedy relpy 'OLD SPOUSE'

Ok.. given that we know PH tests are prone to mis-leading results during cycles then, do you feel I should still have any concerns that the results at the moment are so high? (in relation to the 'normal' range of PH compatibles being 7.0 - 7.6), or can I expect them to drop naturally when the cycle is complete? My tap water normally reads a steady 7.6 you see.

Cheers.

John.

 

[This Old Spouse]

I think the fluctuations are to be expected while you're cycling, which is why it's not recommended to test during this time. Once your tank is cycled and before you add fish, then check it over the course of a day or two to see the results. What's in your tank at this time?

 

[HayzH]

the process of turning Ammonia into Nitrite and Nitrite into Nitrate will cause the PH to rise..the Bacteria breed best around PH 8.0...so this is a GOOD sign.
As has been said..The Ph normal range will only go up to that bluey colour as thats its limit, and it wont register anything higher.
The High range is the one you need right now. keep it as close to 8.0 as possible and things will progress well.

Once your cycle has finished you do a big w/c anyway with fresh water, so it will be back to your normal tap water PH.

 

[jts123]

I think the fluctuations are to be expected while you're cycling, which is why it's not recommended to test during this time. Once your tank is cycled and before you add fish, then check it over the course of a day or two to see the results. What's in your tank at this time?

Ok.. cheers. There are no 'living' things in the tank at the moment. No Fish, No Plants or Wood. Normal 'tank essentials' like: Filter and Heater and two 'cave' ornaments and gravel substrate. But I can't wait to get my first fish!

 

[jts123]

the process of turning Ammonia into Nitrite and Nitrite into Nitrate will cause the PH to rise..the Bacteria breed best around PH 8.0...so this is a GOOD sign.
As has been said..The Ph normal range will only go up to that bluey colour as thats its limit, and it wont register anything higher.
The High range is the one you need right now. keep it as close to 8.0 as possible and things will progress well.

Once your cycle has finished you do a big w/c anyway with fresh water, so it will be back to your normal tap water PH.

Thanks Hayley. I really hadn't realised the fact that PH around 8.0 is a good thing during this time. So.. all looks fine then for now. (I'm just getting so impatient waiting for the levels to become safe for my new fish, but.. better this than put fish through a horrible time or even death huh?)

John.

 

[eaglesaquarium]

The process will cause the pH to FALL, as a result of some of the nitrates showing up in the form of nitric acid.


Have you tested your tap water after letting it sit for 24 hours? Many times, the pH reading for your tap water is not accurate straight out of the tap. Many municipalities will have some gasses, besides chlorine in the water and it stays there while the water is under pressure in your pipe. However, once allowed to flow out, it gasses off. Specifically, CO2 is one of those gasses. This forms carbonic acid in the water and when it gasses off, the pH will rise.



If that is not the reason for the pH rise, then did you add any baking soda? A pH of 8.0-8.4 is the sweet spot for the bacteria you want and many folks do add some baking soda to raise their pH during the cycle.


Finally, if the pH isn't high because of the tap gassing off CO2 after testing the tap, nor did you add any baking soda, the next question is what is in your tank... please stay as specific as possible.