huge pH swings

[Dudester]

I have a 30g mixed reef with 14 gallon sump/fuge, established since 9/05. It contains mostly LPS, softies, and now a few SPS. Since the beginning I've used kalk in my topoff water, and this along with bi-weekly water changes initially kept my pH quite stable at 8.3-8.4, according to Salifert test kits.

As I began adding corals (albeit LPS and softies) my calcium and alkalinity decreased. I then began dosing B-Ionic, and titrated the volume up per the instructions. I was unable to achieve an appropriate calcium level despite adding 45ml of each solution, so I added Turbo Calcium according to your calculator, and this helped immensely. I still had to add 45ml of B-Ionic to maintain my desired Ca level of >400, and for some reason my alkalinity is drifting downward.

For the holidays I got a pH monitor. Since I look at my pH more frequently now, I've noticed that my pH swings from 8.1 just before "lights on" to 8.4 just before "lights off." More concerning is that over the last 2 nights I've noticed that my pH will jump from 8.1 to 8.7 after adding the B-Ionic. It takes several hours for the level to drift back down. This does not seem to harm any of the occupants (as far as I can tell), but I just got a crocea clam and I'm worried that the high alkalinity spikes will harm it.

Do you have any suggestions as to how I can stabilize my pH more?

I'd like to be able to add less B-Ionic since it is highly alkaline, and it's not cheap. Should I try baking soda to give my alkalinity a boost?

Thanks in advance!

 

[Randy Holmes-Farley]

You can add less B-ionic at once, but more times. You can use a version that does not raise pH (B-ionic bicarbonate or my DIY). You can aerate the water more (bringing the spike down faster). You can add it at the lowest pH time of the day.

Higher alkalinity will also reduce the pH spike.

I'd try to keep the pH below 8.5, if possible.

These articles may help:

High pH: Causes and Cures
http://reefkeeping.com/issues/2005-03/rhf/index.htm

A Homemade Two-Part Calcium and Alkalinity Additive System
http://www.advancedaquarist.com/issues/april2004/chem.htm

 

[Dudester]

Thanks for the answer and the link to that great article on high pH. I decided to add my B-Ionic in the mornings (when the pH is at its lowest), and I'll add some baking soda to increase my alkalinity and hopefully decrease my pH as well. My next choice would be to add an airstone to my sump.

Do you feel that 1ml/gallon of system water is a lot of B-Ionic to add on a regular basis?

Thanks again for your help.

 

[Randy Holmes-Farley]

It is at the high end of normal, but not outrageous for a high demand tank (lots of SPS, etc).

 

[Dudester]

FYI, I started adding my B-Ionic in the mornings a few hours before "lights on." My pH is now much more stable, and after adding baking soda, I've been able to decrease my B-Ionic addition while maintaining Ca and alkalinity. Thanks!

 

[Randy Holmes-Farley]

Sounds good!

You're welcome and happy reefing.

 

[Dudester]

Perhaps I spoke (or wrote) too soon. I thought I had corrected the problem, but in fact I'm having a difficult time maintaining alkalinity. The pH is certainly better now that I'm adding B-Ionic in the early mornings. The problem now is that I'm battling a large bryopsis outbreak, and my first step (besides protein skimming and light feedings to reduce nutrients) is to try to raise my alkalinity to about 12. My alk was at 8 and I used your calculator and added 4 tsp. The level increased to about 11, but when I checked the next day it was down to about 9. I added more baking soda and again, the next day, it was down to 8 again. Is the baking soda effect always this short-lasting, and should I expect to have to add it on a daily basis, or is this indicating another problem? Sorry to keep asking you questions, and I appreciate your dedication to this forum.

 

[Randy Holmes-Farley]

The higher the alkalinity, the more additive is needed each day to keep it that high because the demand for alkalinity depends on, among other things, the alkalinity itself. So yes, it is expected that if you want to maintain it higher, you need to add more every day.

 

[Dudester]

I've been adding baking soda almost daily for nearly 2 weeks now. Can this have a detrimental effect on the tank, or is it benign enough to be considered appropriate for daily dosing? My pH remains between 8.2-8.4. My alkalinity drops to about 8 or 9, which is why I keep adding the baking soda.

 

[Randy Holmes-Farley]

Can this have a detrimental effect on the tank, or is it benign enough to be considered appropriate for daily dosing?

It is OK for daily dosing, but a balanced calcium and alkalinity system using it would be better:

An Improved Do-it-Yourself Two-Part Calcium and Alkalinity Supplement System
http://reefkeeping.com/issues/2006-02/rhf/index.php


The concern with baking soda alone is the slow buildup of sodium relative to calcium/potassium/magnesium/etc. Craig models it here:


Simulating the Effect of Calcium Chloride and Sodium Bicarbonate Additions on Reef Systems
http://web.archive.org/web/20030624...twork.com/fish2/aqfm/1998/dec/bio/default.asp

Additional Simulations: The Combined Effect Of Calcium Chloride
/Sodium Bicarbonate Additions And Water Exchanges
http://web.archive.org/web/20010210...twork.com/fish2/aqfm/1999/feb/bio/default.asp

 

[Dudester]

Wow, thanks for all of those article references. I'm already dosing a balanced 2-part solution (B-Ionic, almost 1 ml/gallon of system water), and since it's not cheap, I'm having to supplement with baking soda to increase my alkalinity sufficiently. I guess I could use your DIY fomula instead though. That would certainly cost less!

 

[Randy Holmes-Farley]

You're welcome.

Happy reefing.