Alkalinity "Crash"

[j0tca]

Hi,

About 3 weeks ago I had a Kalk disaster caused by a malfunctioning DIY Nielson. Without going back into the horrible loss of life, the end result was a PH of 10.5. Worried for for 2 remaining fish, I used a mineral acid buffer to bring my PH back down. In retrospect, this might not have been the best idea.

My alkalinity is at 0.5-1. I have massive algae growth feeding from the die-off and PH swings from 7.9-8.45 daily.

I have been dosing my kalk as normal (about 3 gallons daily topoff) for the last 3 weeks and my alkalinity has not raised at all.

I used a buffer for a week straight and though my alkalinity raised temporarily, it dropped back down again.

Does anyone have any sugggestions to this problem?

I have read alot of differing opinions on Baking Soda and was wondering if I could dose that to raise my alkalinity.

Thanks for any help,
Will

[Muttling]

Water changes, water changes, and more water changes.

Randy can probably give all the details, but basically the pH ran up so high that it screwed up several aspects of the water chemistry. Some of those aspects are not readily reversible and the best approach is replacing the water instead of trying repair it.

Of course, you don't want to replace it all at once as that risks even more shock on your specimens. 20% or so water changes every day or so for a week (maybe 2) should get you back on the right path.

[j0tca]

Thanks Muttling,

That was my original approach and I changed 50% of the water immediatley, followed by 5 days of 20% changes. I figured that I had essentially changed all the water by that point so I stopped with the water changes and continued to dose Kalk.

Unfortunatley, water changes do not seem to bring my Alk. back up. This is another point that I wanted to ask about, as I assumed that Alk. was a water chemistry issue, rather than something that was more deeply involved in the system. I. E. , I expected a complete changing of all the water to simply solve the problem but it didn't. How did my alk. stay down with all the water changed?

Will

[Randy Holmes-Farley]

The calcium may be very high. So you may need to keep adding an alkalinity supplement until the calcium comes down. Have you measured calcium?

You can boost the alkalinity with baking soda. That can be done all at once (at least to the normal range), with the baking soda dissolved in water and added to a high flow location. You may need to do that many times before it stabilizes if clacium is very high.

This calculator shows how much:

http://home.comcast.net/~jdieck1/chem_calc3.html

and this article may help:

Solving Calcium and Alkalinity Problems
http://www.advancedaquarist.com/issues/nov2002/chem.htm

[j0tca]

Thanks Randy,

I've read, and re-read those articles.

Will baking soda and buffers result in a lasting higher alkalinity?
I used a whole package of buffer, dosing daily for about 10 days the recommended dosage, without any lasting effects. My alk would raise to 3 or so and then drop the next day.

Most articles seem fuzzy or contrary to each other on whether baking soda will maintain Alk.

My calcium is 225 ppm,

When my PH went high, my calcium all precipitated out, it looked like a snow storm.

Will

[Randy Holmes-Farley]

Will baking soda and buffers result in a lasting higher alkalinity?

Most articles seem fuzzy or contrary to each other on whether baking soda will maintain Alk.


It is as lasting as anything that you can add at one time. Going forward, you should expect to have to continually add alkalinity supplements of some sort. Calcium too.



My calcium is 225 ppm, When my PH went high, my calcium all precipitated out, it looked like a snow storm.

I'm surprised the calcium is that low. I don't know how that might have happened, even with a snow storm. Assuming that it is correct, I'd boost the calcium with calcium chloride. :)

[j0tca]

I've calibrated my test kit with a reference and tested my system a few times, I'm sure it's correct or close to it.

In one of your articles you suggest that in the range of extremely low Alk and low Ca, one cannot correct the problem with limewater or a alk buffer, it must be corrected with calcium chloride. Could you tell me why that is?

I started adding baking soda to try and bring up my Alk.

My total system is 175G so I added 3 tblsp of baking soda, this dropped my ph from 8.17 to 8.04 immediatley. My kalk will start adding tonight and bring the Ph back up.

One thought that crossed my mind is that my huge Ph swings might be attributed to an excesive amount of green algae. This large amount of plant life might be creating a substantially larger CO2 daily swing than is normal.

Unfortunatley, the algae will start to die off when I'm fixing my Ph/Ca/alk problem. As seems to always be the case, I'll never know if the algae directly contributed, or was the cause of the problem. This hobbie seems very good at preventing clean diagnositics.

Thanks for all your help,
Will

[j0tca]

Oh, why does the baking soda bring the Ph down? If it is rasing carbonate alkalinity, shouldn't it bring the Ph up?

Thanks,
Will

[j0tca]

Oh, and one more addition FYI,

I got my protein skimmer back working today after ithe pump had burnt out during my Kalk disaster. My Ph was swinging from 7.9-8.4 daily only raised to a max of 8.15 today. Interesting how increased airation dramatically changes the CO content, and Ph of the water.

Will

[Randy Holmes-Farley]

In one of your articles you suggest that in the range of extremely low Alk and low Ca, one cannot correct the problem with limewater or a alk buffer, it must be corrected with calcium chloride. Could you tell me why that is?

It is because limewater adds 20 ppm of calcium for every 1 meq/L (2.8 dKH) of alkalinity. So if you raised calcium by 200 ppm, alkalinity would try (and fail) to rise by an additional 10 meq/l (28 dKH).

Oh, why does the baking soda bring the Ph down? If it is rasing carbonate alkalinity, shouldn't it bring the Ph up?

pH in reef aquaria is controlled by many factors, but most directly by carbon dioxide and alkalinity. While baking soda adds alkalinity, it also adds "extra" carbon dioxide, lowering pH.

I discuss such issues and show the experimental results, in this article:

The Relationship Between Alkalinity and pH.
http://www.advancedaquarist.com/issues/may2002/chem.htm

This one shows how CO2 impacts pH:

Low pH: Causes and Cures
http://reefkeeping.com/issues/2004-09/rhf/index.htm

One thought that crossed my mind is that my huge Ph swings might be attributed to an excesive amount of green algae. This large amount of plant life might be creating a substantially larger CO2 daily swing than is normal.

Yes, that can contribute to a large pH swing, and aeration will reduce it, as will raised alkalinity.

My Ph was swinging from 7.9-8.4 daily only raised to a max of 8.15 today. Interesting how increased airation dramatically changes the CO content, and Ph of the water.


Absolutely. Perfect aeration would result in zero pH swing. :)