Low PH

[DonW]

If your using buffers, you are skewing the waters chemistry. All ph buffers raise alk. A simple test will tell you exactly why your ph is low. Simply take some water outside a airate. If the ph goes up you probably have a co2 issue. Although kalk will raise your ph its just a bandaid and is a great bandaid for night time ph issues but not when your having problems 24/7. If you have good aeration and a decent alk level, Id look more at high nutrients and more water changes.

Don

 

[BCT182]

But I caution

It is a messy solution to it.

Why messy?

 

[BCT182]

Do you run a skimmer.... If so this should blow off any excess co2.... I would check Ca and Mg levels.... Bring up Ca with kalk slowly and add MG.... This will fix PH if those are low also...

Yeah Im running a kent marine skimmer thats very effective.

 

[BCT182]

If your using buffers, you are skewing the waters chemistry. All ph buffers raise alk. A simple test will tell you exactly why your ph is low. Simply take some water outside a airate. If the ph goes up you probably have a co2 issue. Although kalk will raise your ph its just a bandaid and is a great bandaid for night time ph issues but not when your having problems 24/7. If you have good aeration and a decent alk level, Id look more at high nutrients and more water changes.

Don

Will do, thanks EVERYONE for jumping in on this one. I think I have the advice I need now to hopefully correct the problem.

 

[twilliard]

Why messy?

Uncontrolable salt creep, it was a never ending battle for me.

 

[BCT182]

I just tooka a fresh from the RoDi machine 5 gallon bucket of water and tested it. 8.1
I added the 2 1/2 cups instant ocean reef salt.
I put a seio in the bucket and unscrewed the air intake on the powerhead to suck some oxygen into the water.
I allowed in two hours to mix/disolve the salt as well as airerate the water to raise the PH.
I tested it......... 7.6
WHAT THE *@#($ IS GOING ON!!!!
I have always bought water from the LFS and am new to mixing my own. How can I sucessfuly keep a damsel if I can't figure out the *&$@ing PH!!!!
I should add, my ph stick is calibrated!

 

[steve-s]

What is the pH/alk in your display tank?
How long after the salt is added are you testing the pH and how high is the alkalinity getting?

One thing that comes to mind here (a long shot at that) is the immediate addition of the salt will shoot up the alkalinity forcing out a majority of the CO2. This will cause a spike in he pH but it would be short lived. The water will then try to regain "balance" by sucking up alot of CO2. This can cause the ph to crash. Adding air like you've done with the powerhead will have zero effect. O2 does not influence pH, CO2 does.

Moving to Boomers forum to see if he's got something better.

Cheers
Steve

 

[BCT182]

The ph in the display tank is 7.6/7.7 and I am going to go buy a alkalinity test this morning, as well as an MG if thats still nessessary. I added the sal to the RoDi water just about as soon as the bucket was full and ready. I tested it before the salt was added (8.1) and after (7.7). I had allowed the water and salt to stir in the bucket for 2 hours.
My display tank doesnt even have a chance at good ph if the waters at 7.6 before I even pour it into my sump.

I DID put an airstone in the sump and have been really bubbling things up for over 18hrs now and the ph has only dropped from 7.7 to 7.6

I thought the air stone was supposed to help raise the ph?
I have been dripping kalkwasser and it has done nothing either.

 

[BCT182]

Bump Bump!

 

[steve-s]

Your problem isn't buffering or the salt, it's trapped CO2 in your house/appartment. If the pH of the salt and the tank are the same, it's not the water. Test the alkalinity to be sure but I doubt that's your issue.

Do you keep the doors/windows closed most of the day and/or so you use AC? Are your appliances gas or electric?

He's a test to try. Remove a good sized glass of tank water and place it outdoors where it can aerate easily. Be sure it does not get debris from animals/tree's. If you have a airpump w/stone that will help all the better. After about an hour, retest the water and see how much it differs from the tanks pH.

Cheers
Steve

 

[steve-s]

One more thing, when you get the alk test kit, take your pH kit with you. Have the LFS test their water using your kit. That will help verify if you have a bad kit.

Cheers
Steve

 

[BCT182]

I use a ph electric probe. I just checked it calibration with the 7.01 solution.
It was dead nuts on.

 

[Boomer]

How did all this get here Someone must have moved it. I'll check it tomorrow

 

[NaH2O]

BCT182 - I would do what DonW and Steve have suggested, and test the pH of the water after being outside. Low pH was a problem for me because in the winter and summer my house is sealed up tight (I guess that means I have great windows ), and I have all gas appliances. Since it has been unseasonably cool, the windows have been open and all is well with the pH. I drip kalk 24/7, and it helps to maintain better pH levels, even when I'm on full winter mode with gas running all the time.

Don't forget to follow up with your parameter tests: alk, Ca, Mg, salinity. Also, just for kicks, I'd recalibrate your probe (not just check it against one solution).

 

[Boomer]

Lets start from the beginning

Your RO/DI water does not have a pH of 8.1 or anywhere near that. RO/DI water has little or no "needed ions" to measure pH so you get a false reading. You need a very special pH mete to do this. The pH of RO/DI water is often below 7, in the 6's, reason is that as soon as the RO/DI water is exposed to air it pick-ups CO2 which lowers its pH.

Aeration, be it airstone or powerhead may or may not help. If a room has allot of trapped CO2 such applications will actually lower the pH, as the room air CO2 has a higher partical pressure than the water. This drives CO2 into the water lowering the pH. If the room air partical pressure is lower or normal, then aeration will help drive off the CO2 and raise the pH.

pH problems should not be fixed with bufffers, unless it is a Alk and pH problem. A pH fix is best by adding kalk. The kalk has a OH- part to it, which combines with the CO2, removing it and producing HCO3-, a buffer. The other issue is when buffers are added they actually not only raise the pH and Alk but also the CO2. Tanks with higher Alk's will have higher CO2 but this is normal and will not effect the pH as the system is balanced. However, the continued addtion of buffers, without knowing where you are at, Ca++, Mg++ and Alk can skew the system. If enough buffer is added it will pull Ca++ anfd Mg++ out of solution. This is good at times if the Ca++ or Mg++ are to high.

Your issue here is where is the CO2 coming from. It may be room air CO2 but may also be just tank CO2 form an overloaded tank, i.e, to much food, animals , poor circulation etc..Take two glasses of water and aerate one in the house and one outside the house. You do not nned to really measure its pH, although that is fine also. You can just put some pH indicator in the glasses and then aerate them. As they are aerated the colored water will change color telling its pH. If you really have an indoor CO2 probelm the glass out side will have the biggest shift in raising the pH.

 

[Boomer]

I though I posted this but I guess I did not sent it.

I DID put an airstone in the sump and have been really bubbling things up for over 18hrs now and the ph has only dropped from 7.7 to 7.6

This tell me that more than likely you have high room air CO2

Steve-s

That trick of dumpinng salt will not work, the CO2 will just get converted. In a carbonate system pH is a function of the ratio of CO2:HCO3-:CO3--. As the pH rises there will be an increase of the stuff to the right and as it falls there will be increase to the stuff on the left. The ratio of these three, if you knew them, will give the pH. It can be seen in a visual pC-ph Diagram. This is one for FW. A seawater one will look the same, just move the graphs and vert line to the left, so the first 50% croos-over is at 6.1 an the second 50% cross-over is at 9.1. The Alk will also not shift, it is just that SW can hold less CO2 than FW and these ratios will shift from FW to SW ratios. Meaning FW and SW ratios are not the same and they also shift with temp. In a pure water system they are only a function of TDS/salinity and temp.

Example for seawater;

______________20C @ 34.3 ppt____________

pH............CO2..............HCO3-.............CO3--

7.5...........3.14 %..........94.8 %.............2.03 %

8.0...........1.02%...........92.8%..............6.27

8.3...........0.46 %..........87.7%.............11.86%

How high the Alk is does not matter, it just means in these diagrams there will be more in mg / l of each but the ratios remain the same. Meaning at an Alk of 3.0 meq / l the ratios are the same as they are at 2.0 meq / l. You just have more Alk at 3.0 meq/l.

 

[BCT182]

I DID put an airstone in the sump and have been really bubbling things up for over 18hrs now and the ph has only dropped from 7.7 to 7.6

This tell me that more than likely you have high room air CO2

Thanks for all the help everyone!
So what do you recommend I do then? Drip kalk?

 

[Boomer]

First, I would start with a water change, say 25 %, as I think your tank is also out of wack. After the change monitor the pH, Alk, Ca and maybe Mg every day and see what happens. Post them here, so we can see what is going on and what is happening rather than just firing the gun, adding x, y or z

 

[BCT182]

Will do. The thing I still don't understand is when I make fresh ROdi water and mix the salt outside with a powerhead thats mixing and sucking in air and making bubbles... Why does it test at 7.6? before it ever makes it to the tank. If I do a 25% water change and add saltwater with a PH of 7.6, I should expect my PH not to change.... right?

 

[Jimbob]

If possible, you might try letting your new saltwater mixture circulate and age for at least 24 hours... 48 hours is even better. Another possible reason it is testing at 7.6 is because the the RO/DI water is so low (likely below pH 7 as Boomer mentioned earlier) from the get-go. Even the best salt out there will not raise the pH up to 8.0 - 8.2 in the matter of just a couple of hours.

This is why Bob Fenner, Anthony Calfo and several other notable authors suggest trying to let the new mixture of sw age for a full week if possible... it allows time for things to equalize as much as possible. As Boomer eluded to, fresh RO/DI water absorbs a great deal of CO2 when first exposed to atmosphere. It takes time for the salt to fully dissolve and for the excess CO2 to eventually off-gas from the solution.

Of course, as mentioned earlier, if CO2 levels in your house are very high, then your fighting an uphill battle. Did you try one glass of water inside and one outside, aerated and using the pH color fluid like Boomer suggested? If so, what were your results?

-Jimbob