Daily pH fluctuation

[BrookR1]

I just wanted some feedback on the daily pH fluctuation that my 40 gallon tank normally experiences. I'm searching for a way (if possible) to clip the highs and lows. Temp-79-81.5.

My lighting cycle (1 20K 175 MH 18" above the water and 1 10K MH 12" above the water) is:
6am 20K on,
7:30am 10K on
7:45am 20K off
5:30pm 20K on
5:45pm 10K off
7:15pm 20K off

pH: 6am 7.95-8.05: at this point, I add enough Kalk to raise the pH to 8.15

8:30am 8.18-8.2
5pm 8.26-8.3
8:30pm 8.05-8.1 at this point, I add enough Kalk to raise the pH to 8.15-8.2.

My SPS corals have been growing like weeds, but my open brain seems a little stressed. My Alk tested at 10 dKH yesterday and my Ca was around 390. The only thing that worries me is the maximum daily fluctuation of almost .3. I would like to reduce this to .2 or lower per day. I tried to "center" the pH at 8.25 a couple of times using more buffer, but that that only lead to higher highs and lower lows.

Any suggestions?

Thanks
Brook

[Boomer]

Brook

You need to get a kalk doser and hook it up to a timer or turn it on and off manually and run it from say 8:00pm - 8:00am. They are very cheap to make.

Here are some examples;

http://www.reefs.org/library/diy/diy9.html

http://www.hawkfish.org/infoctr/kalkdrip.htm



I use to play with ones like this, only they were under the tank. A Tetra Lufta air pump was attached to the "10 PIECE OF STANDARD 1/4" AIRLINE TUBING and the pump hooked up to a timer. The air would pressurize the container and push the kalk up the "60 TUBING". You can now control the flow rate with the dial on the pump and a control value on the effluent.

http://www.nfmas.com/forums/index.php?showtopic=2&st=0&#entry7

[BrookR1]

Thanks for your response. I switched to the kalk slurry method because using a gravity feed was unreliable...it always seemed to clog/stop in the middle of the night. Attaching an air pump and running it on intervals throughout the night sounds like a great idea. I will give it a try.

[Randy Holmes-Farley]

I don't think that pH range is a problem, but in general, more aeration reduces the swing, and perfect aeration with normal air will eliminate it altogether.

[BrookR1]

What about adding an extra airstone to my tank only at night, after my kalk additions? It would save me the trouble of "re-tuning" my methods.

I already leave a nearby window open and I run a fan across the surface. I measured my O2 using the Salifert test kit a few weeks ago, and (if I can remember correctly), it was 7.1. The reading was within the "normal" range. When I tested, it was in the daytime, so I'm going to test at night just for giggles.

[Randy Holmes-Farley]

An airstone is not as effective as a skimmer, and may or may not make a big change in the daily swing. It may also lower the pH overall if the house air has excess CO2 in it.

FWIW, O2 has nothing to do with CO2 levels. :)

[Boomer]

Do you have a sump, if so put an airstone in there and let it roar at night but get some kind of baffle in there so the spray is not shooting out all over the place. There is also the issue of high room air CO2 which will make it even worse by aeration. That is why Randy said normal air and high room air CO2 is not normal ;)

[BrookR1]

I actually run two skimmers. One hang-on (CPR BakPak) on the main display and one hang-on (Prizm) in my 20 gallon sump. Hmmm...then CO2 levels. Maybe the extra skimmer is pumping more CO2 into the main tank. Maybe if I closed off my bedroom door at night?

[Randy Holmes-Farley]

Maybe if I closed off my bedroom door at night?

That might help.

Or you can breathe less. :D

[Boomer]

Yah, by all means stop breathing that will fix the problem for sure :

[cbadrik]

I have also noticed my ph go from 8.05 - 8.45. Randy when you say "more aeration reduces the swing" do you mean more top water movement?

[Boomer]

That is one of 4 ways

1. Water motion at the suface.

2. Airstone aeration

3. Skimmer aeration

4. Degassing tower aeration.

[cbadrik]

Boomer how do I do the following:

Skimmer aeration

Degassing tower aeration.

I have a ASM G2 skimmer. What adjustment should i make to help me reduce the ph?

Im sorry but I dont understand what is a degassing tower aeration?

[beaver]

Mine were solved a week after my geo cal reactor was dailed in.

Also I believe in running a quality skimmer, right know it is a downdraft, but soon I am trying a beckett mod.

On a lighter note I was accepted to the Dauphin Island Sea lab today......:
http://www.disl.org/

Good luck
:thumbsup:

[Randy Holmes-Farley]

I have also noticed my ph go from 8.05 - 8.45. Randy when you say "more aeration reduces the swing" do you mean more top water movement?

Any way of increasing the gas exchange, which is best done with a turbulent top of the tank and a big skimmer that sucks in a lot of air.

What adjustment should i make to help me reduce the ph?

IMO, your pH range is jsut fine, and I wouldn't try to reduce the pH.

[Boomer]

Cbad

I agree with Randy your pH is fine. You do not need better gas exchange, which will just make it go higher. :D Brook as had low pH problems. What are you adding to you tank to raise the pH just out of curiosity ?

Degassing tower; Is a device to drive off unwanted gasses. Water trickles down from the top of a large cylinder. The cylinder sometimes is filled with baffle plates or a very open media and high volume air is driven up through the bottom to the top where it vents out. As the air rushes upward through the falling water droplets, it pulls out the CO2 from the water.

[cbadrik]

I'm really not adding anything to raise the ph except for running the calcium reactor. I just have the solenoid it hooked up to a timer which shuts off during the night for 6 hours.

So for it to go from 8.05 to 8.45 all in one day is fine. At what level should I start worrying about the ph?

[Randy Holmes-Farley]

from these articles:

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

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

Reef Aquarium Water Parameters
http://www.reefkeeping.com/issues/2004-05/rhf/index.htm


What is the Acceptable pH Range for Reef Aquaria?

The acceptable pH range for reef aquaria is an opinion rather than a clearly defined fact, and will certainly vary based on who is providing the opinion. This range may also be quite different from the "optimal" range. Justifying what is optimal, however, is much more problematic than that which is simply acceptable. As a goal, I'd suggest that the pH of natural seawater, about 8.2, is appropriate, but reef aquaria can clearly operate in a wider range of pH values. In my opinion, the pH range from 7.8 to 8.5 is an acceptable range for reef aquaria, with several caveats. These are:

1. That the alkalinity is at least 2.5 meq/L, and preferably higher at the lower end of this pH range. This statement is based partly on the fact that many reef aquaria operate quite effectively in the pH 7.8 to 8.0 range, but that most of the best examples of these types of tanks incorporate calcium carbonate/carbon dioxide reactors that, while tending to lower the pH, keep the carbonate alkalinity fairly high (at or above 3 meq/L.). In this case, any problems associated with calcification at these lower pH values may be offset by the higher alkalinity. Low pH primarily stresses calcifying organisms by making it harder for them to obtain sufficient carbonate to deposit skeletons. Raising the alkalinity mitigates this difficulty for reasons that are detailed later in this article.

2. That the calcium level is at least 400 ppm. Calcification becomes more difficult as the pH is lowered, and it also becomes more difficult as the calcium level is lowered. It would not be desirable to push all of the extremes of pH, alkalinity, and calcium at the same time. So if the pH is on the low side and cannot be easily changed (such as in an aquarium with a CaCO3/CO2 reactor), at least make sure that the calcium level is acceptable (~400-450 ppm). Likewise, one of the problems at higher pH (above 8.2, but getting progressively more problematic with each incremental rise) is the abiotic precipitation of calcium carbonate, resulting in a drop in calcium and alkalinity, and the clogging of heaters and pump impellers. If the aquarium pH is 8.4 or higher (as often happens in a tank using limewater), then it is especially important that both the calcium and alkalinity levels are suitably maintained (that is, neither too low, inhibiting biological calcification, nor too high, causing excessive abiotic precipitation on equipment).

3. Likewise, one of the problems at higher pH (anywhere above 8.2, but progressively more problematic with each incremental rise) is the abiotic precipitation of calcium carbonate, resulting in a drop in calcium and alkalinity, and the clogging of heaters and pump impellers. If you push the pH to 8.4 or higher (as often happens when using limewater), make sure that both the calcium and alkalinity levels are suitably maintained (that is, neither too low, inhibiting biological calcification, nor too high, causing excessive abiotic precipitation on equipment).

4. Transient upward spikes are less deleterious than transient downward spikes in pH.

[cbadrik]

Thanks for all you help guys.

Chris

[Randy Holmes-Farley]

You're welcome.

Happy Reefing. :)