Low PH problem

[gnatp2]

I recently recalibrated my ph probes (i have 2 neptune lab grabe PH probes in my tank). They range from 7.7 -> 8.0 throughout the day. Since my ph has been low, I'm trying to fix it.

I have read through "Low PH, causes and cures" http://reefkeeping.com/issues/2004-09/rhf/index.php and I'm still having problems.

Here are my current parameters as of this morning.
PH 7.7
Alk (salifert) 9.9
Alk (lamotte) 7.9
Calcium 470
Mag 1410

I performed the airation test using the room air and the ph moved from 7.7 to 7.83 in 1 hr. Using outside air, it moved from 7.7 to 7.88.

I dose kalkwasser as my primary source of calcium and alk. I also use a calcium reactor, but I have it set very low. I unplugged it for a night completely and the ph did not rise.

Fully airrated, my PH should be up at 8.3 using a conservative alk estimate. Given that my ph only went up to 7.88 after airrating it with outdoor air, why is my PH so low?



Nate

[gnatp2]

After leaving the water for an additional 4 hours using outside airrated air, the ph only climbed up to 7.91.

I just made a batch of freshly mixed saltwater. Came up with 8.15 PH and 8.2 alk (salifert).

Looking at the article, it seems like my only issue really could be too much co2 in the water, but even after excessive airration, it isn't climbing up that much.

Confused,
Nate

[m2434]

Well, I see you live in Manhattan? I'm not sure how good the air quality is there... may have llots of CO2 outside as well.

Are you rdripping kalk at night.

Also, I'm not so sure about salifert these days.. might try another testkit.

[Aurora D.]

Maybe a large water change would help you some.

[phljess]

If you are running a kalk reactor and ato, you could have the reactor stir several times a day for short periods of time to make sure you are receiving saturated kalk when you dose. You may also want to increase evaporation to get more kalk into the water, just a couple of ideas.

[gnatp2]

Originally posted by m2434
Well, I see you live in Manhattan? I'm not sure how good the air quality is there... may have llots of CO2 outside as well.

Are you rdripping kalk at night.

Also, I'm not so sure about salifert these days.. might try another testkit.

There are quite a few others here in the city that don't have the PH issues that I do, so I doubt that the whole city has extremely high co2. Also, this drift downward has slowly happened over the past few months, so I used to be ok with my PH.

I'm dripping the kalk automatically whenever it comes on as the autotopoff.

I hear ya about the salifert alk test kit, which is why I use lamotte as well.

Thanks,
Nate

[gnatp2]

Originally posted by phljess
If you are running a kalk reactor and ato, you could have the reactor stir several times a day for short periods of time to make sure you are receiving saturated kalk when you dose. You may also want to increase evaporation to get more kalk into the water, just a couple of ideas.

I'm running the deltec kalk stirrer, so I'm sure the kalk is extremely saturated.

I thought about increasing my evaporation, but then I may be overdoing the calcium into the tank. I'm already on the higher side at 470.

Nate

[m2434]

Originally posted by gnatp2
There are quite a few others here in the city that don't have the PH issues that I do, so I doubt that the whole city has extremely high co2. Also, this drift downward has slowly happened over the past few months, so I used to be ok with my PH.

I'm dripping the kalk automatically whenever it comes on as the autotopoff.

I hear ya about the salifert alk test kit, which is why I use lamotte as well.

Thanks,
Nate

Depends what your downwind from I guess...
dripping kalk at night helps - how much is your ATO using every day? Can you have it on a timmer so it only goes on at night?

As to the CO2, it can take some time to get rid of excess, but it depends on the gradient i.e. the lower the levels are outside, the faster it can "escape there". I'm sure in any city, the CO2 levels are fairly high, so CO2 probably won't escape as quick as in the country and it may take longer for levels to equalize. You also, probably have slighlty high CO2 from the ca reactor, and by the time it starts to exit your system after you turn it off at night, more is already acumulating from any algae in your tank.
just my .02...

Of course, your pH isn't that bad, I've seen much worse...