Varied Ph result

[dearis]

Hi there,

today I took some water to my LFS and had the water tested on a tank i', cycling ph was 8.2, amonia 0, and nitrate is 10ppm. I also calibrated my ph testerin ph7 test solution. No the thing is when I got home I tested my tank and it came out as ph7.9

Now why was this?

Regards Darren

 

[Omni2226]

PH varies a lot 24 hours a day. Lighting/darkness, adding topoff water, a lot of things influence PH. As long as it is not changing greatly..( Say from 8.4 dropping to 7.0) in a very short time,( say 2 hours), then its probaly ok.

A lot of people light the refugium/sump with a cheapo lamp 24/7 to help reduce large PH swings.

In the daytime mine goesup to about 8.2 8.4 and drops to about 7.8 7.9 at night.

 

[dearis]

That might answer the question, the lights were not on in the tank when i collected the sample, then i re-tested when i got home lights were on. How does the day/night shift affect fish and corals?

Thank you Regards Darren

 

[Sponge_Bob]

All photosynthetic organism will take CO2 and release O2 under light. When the light is turned off, it does the opposite and releases CO2 in the tank. It's that extra CO2 that lowers your pH. My opinion.

 

[Omni2226]

Im no chemist so others with knowledge need to answer that.

All I know is it drops during dark periods and rises during the lighted hours.
As far as I know the Sun and Moon phases have no influence on PH.

Many people run their photoperiod from midday to late at night because they work dayshifts and dont want to come home to a dark tank.

Mine runs from 9:00 AM till 12:00 AM.

 

[Sponge_Bob]

I'm not a chemist either but a chemical process technician. Here is why an increase of CO2 will lower the pH :

CO2 + H20 -----> H2CO3 -----> HCO3- + H+

H+ is an Hydrogen Ion and will lower pH. The abbreviation pH means Potential of Hydrogen.

HTH.

 

[dearis]

G'day,

well it did not change overnight, I got up at 2am and re-tested it was 7.9 now i can see im going to have to re-learn some chemistry however the fact that it has been stable when i have tested 7.8-79 either with liquid test and or digital kit do i need do do something about it?

I have so calcium carbonate rock that is ussually for cichlid tank(photo below) will this assist in boosting ph? ar just act as a buffer?

Regards Darren

 

[Anonymous]

what i would do to determine the problem is to airate the sample and test to see if the ph comes up. if it does then there is not enough gas exchange in the tank and you can work with that. if thats not the problem then look at adding carbonate buffer. this should raise the ph to the desired level and then stabilize. if you feed alot and have a high bioload then it will drop down again and you will need to find a skedule for changing water and adding buffer or reduce your bioloading.

 

[Anonymous]

I think all the replies here are right on.

In salt/reef we use calcium carbonate rocks and substrait to buffer the ph.

And the drop at night is due to increased carbon dioxide.

My tank varies from 8.4 just before lights out to 7.9 or lower just before lights on. With no adverse effects. I use calcium carbonate (crushed oyster shells) in a trickle filter with 5x water flow. So when the ph drops at night that drop is limited by the calcium carbonate. And calcium carbonate is (slowly) added to the system.

Plus I use an large in tank refugium with macro algaes so the just before lights out ph recovers. So that during a 24hour period the tank becomes a net consumer of carbon dioxide and producer of oxygen.

But before the calcium carbonate and refugium I had a much more constant and much lower ph. And had trouble keeping any new desirable fish longer then 3 weeks.

 

[Sponge_Bob]

Seachem Marine Buffer 8.3
Use as directed.
Change salt brand... might help a bit. I had the same problem when using Red Sea salt mix and solved my problem by switching to a brand X salt mix made in Japan that sells dirt cheap.

 

[Anonymous]

Seachem Marine Buffer 8.3
Use as directed.
Change salt brand... might help a bit. I had the same problem when using Red Sea salt mix and solved my problem by switching to a brand X salt mix made in Japan that sells dirt cheap.

That doesn't really solve the problem. It just artificially raises the PH to mask the real problem. That's like using white-out on a computer screen so you don't see your spelling error.

It's probably just an excess of Co2 due to the house being closed up. I don't think it's really anything to worry about. Using chemicals to mask the problem can make it a lot worse.

 

[FragMaster]

I agree with everything but the co2 build up due to a closed up home.
I dont disagree persay, I would just like a better explenation.
Unless the house is hermeticly sealed or there are way to many ocupants I dont understand how this would be possible?

 

[Sponge_Bob]

Seachem Marine Buffer 8.3
Use as directed.
Change salt brand... might help a bit. I had the same problem when using Red Sea salt mix and solved my problem by switching to a brand X salt mix made in Japan that sells dirt cheap.

That doesn't really solve the problem. It just artificially raises the PH to mask the real problem. That's like using white-out on a computer screen so you don't see your spelling error.

It's probably just an excess of Co2 due to the house being closed up. I don't think it's really anything to worry about. Using chemicals to mask the problem can make it a lot worse.

Ok... so all buffers are just like white-out on a computer screen. And the real answer to his problem is related to a house that is too air tight without any air circulation. I see. The house is so closed up that humans are able to survive in it, having a demand in O2 far greater than a fish, but a fish can not and the air is so saturated with CO2 that the CO2 is trapped inside the tank and that explains why his pH is low. Of course, humans are not bothered by all that CO2.

Do you know what a buffer is and how it works? Do you know how and when crushed coral or aragonite sand will kick in to maintain your pH? Do you know the relation between alk and pH? Do you even have a clue about the above questions?

That "closed up" house explanation is so far fetch that it's not even funny.

Anyway, I gave my answer is backed it up with a scientific explanation. Now I'm not about to give you a crash chemistry 101 course here.

End of discussion for me.
PS: No, I'm not in the mood tonight. S**t happens. Signing off.

 

[FragMaster]

You are two steps from the short bus sponge bob I swear to god!
LOL!!!! :lol: :lol:

 

[Nautilus1]

During the day time the Co2 is used up by photosynthesis fixing carbon. At night, the excess CO2 combines with the water and makes carbonic acid. This will lower the pH along with the hydrogen protons (H+). To avoid this , use a refugium that has the lights going on when the main tank lights go off. There is not too much Co2 in your home, if there was than u could control ur ph by opening the windows. LOL

 

[trido]

In support of Guys post regarding inadequate ventilation causing elevated CO2 levels. YES it is VERY possible. For six years I installed windows for the airport (noise remedy) We were required to leave 1.5 inches of space under bedroom doors and people literally couldnt burn a fire with out opening a window until we installed what was called a "fresh 80". We were also required to add "furnace mods" drawing 20% fresh air into the house when the furnace would come on. The Idea being that the house is so air tight that you will run yourself out of oxygen. Most new construction houses are this air tight . I could go on but there is no need to ramble. It is possible.

 

[Anonymous]

Do you know what a buffer is and how it works? Do you know how and when crushed coral or aragonite sand will kick in to maintain your pH? Do you know the relation between alk and pH? Do you even have a clue about the above questions?

That "closed up" house explanation is so far fetch that it's not even funny.

Anyway, I gave my answer is backed it up with a scientific explanation. Now I'm not about to give you a crash chemistry 101 course here.

End of discussion for me.
PS: No, I'm not in the mood tonight. S**t happens. Signing off.

Yes, I am quite familiar with the subjects you mentioned. Is there a specific question you had in mind that I can help you with?

 

[Nautilus1]

Interesting point Guy. Hpwever, The reasons for installing those things in airports and in house are not for fish tanks. Given the soluability of Co2 in water I find it hard to believe that Co2 in the home can effect fish tank pH., I just dont see it happening.

 

[FragMaster]

Actualy having it explained in that way I can totaly see it now.

BTW Guy: I wasnt hopping on a band wagon It was a legitimate question

Trido88: I can totaly see how a new home would do that if proper ventilation wasnt installed.
Thank's for the explination.

 

[ChrisRD]

As someone already mentioned, many pH problems are caused by poor gas exchange. Something as simple as having a tight fitting lid on the tank, inadequate aeration (common when there is a lack of surface agitation/circulation and/or a skimmer is not being used), etc. can result in poor gas exchange and depressed pH levels.

Many solve depressed pH problems by simple solutions like removing/ventilating tightly sealed lids/canopys, moving the air intake to their skimmer outside of a poorly ventilated stand, or even having the skimmer draw air from outside (yes, whether some people care to believe it or not the idea Guy mentioned regarding excessive CO2 levels in modern homes effecting aquarium pH is not far fetched).

I also agree with Guy's recommendation not to add buffer to resolve a low pH situation. If you test alk and it's low, then by all means supplement it, but do not dose buffer based on pH values alone.