Notice a Drop in your pH???

[Guest Bemmer]

Hey all,

About 3 or 4 days ago, I noticed a drop in my pH for no reason that I could explain. I have two pH monitors on the main system. They have both been calibrated recently so I trust their accuracy...as best I can since they are .13 off from one another. Anyway, my pH dropped below 8.0 close to 7.83. I got some Seachem buffer and that helped raise the pH up to 8.3 but then it settled back down to around 8.0.

 

I posted this drop on RC and Marc (Melev) posted that his dropped as well as several others on RC below 8.0. Just curious if there is an environmental thing going on or what.

 

BTW, the drop in my pH occurred before I added the calcium reactor so that is not the immediate cause for the drop.

[Guest JasonD]

You might try opening some windows in your house...increased atmospheric carbon dioxide can lower pH (by producing carbonic acid in the tank).

Edited May 16, 2007 by JasonD

[bigJPDC]

selling all those bags of chaeto?

[dhoch]

Here are some thoughts:

 

1) Did you switch on your AC around that time (and seal your house)?

 

2) Any changes in lighting recently?

 

3) ANY and I mean ANY other system changes (not matter how benign)....

 

Dave

[ReeferMan]

i noticed too that my ph has dropped since putting on the AC and my levels are about the same. I cant keep mine up as well. Goes up and drops back down

[flowerseller]

I cant keep mine up as well. Goes up and drops back down

WE'VE ALL HEARD THIS ABOUT YOU CHRIS!

Could it be stress?

 

dhoch's thoughts are more inline with my thinking re AC and less evaporation meaning less kalk additions.

[dhoch]

Actually I wasn't thinking less evaporation = less kalk additions.

 

Sealing your house increases the ambient amount of CO2 in your house (kinda like when we have a party at chip's place). I think the AC may also add to this.

 

That makes for more CO2 in the water = Lower pH.

 

Dave

[Gatortailale]

- do you dose kalk (is it hooked up to auto topoff or dosing pump)

- age of kalk in reactor

 

-do you use phosban or some other type of phos media?

- ask tgallo about phosban sucking alk out of water if large amounts are used.

 

- what is your alk and what were numbers at time of drop vs. #'s today.

 

- bringing online a calcium reactor will in some ways depress your ph #'s - especially if your adding to much co2 to reactor and / or not dosing kalk at same time to help offset ph drop.

[YBeNormal]

I go with the air conditioning theory. Either that or global warning.

[flowerseller]

Actually I wasn't thinking less evaporation = less kalk additions.

 

Sealing your house increases the ambient amount of CO2 in your house (kinda like when we have a party at chip's place). I think the AC may also add to this.

 

That makes for more CO2 in the water = Lower pH.

 

Dave

That also makes sense but in a house that big?

 

I guess you're hinting at another pH experiment one evening huh?

[vaironman]

Hello Bemmer,

 

I notice the same thing when I started turning on my home AC and fan circulation. Tank is 150G in basement with dual chambers CA reactor and Kalk reactor. I have to crankup the Kalk in the eve and it'll go back down by the morning.

 

Anyone has advised on what I should do to stabilize the PH is very much appreciated.

 

Thanks in advance,

 

KLee

[dhoch]

Circulate more air into your house...

 

best way is to open the windows!

 

Dave

[Guest Bemmer]

Thanks to everyone for responding.

 

As it relates to the a/c, yes it is running and I have an open vent right behind the fish tank in the fish room to keep the room and tank cooler. In our house, if the a/c is on, the windows are closed so the house is sealed so to speak.

 

Yes, I dose Kalk with a kalk stirrer. I put in about a drop a second. It runs 24/7 but this has been running long before the pH drop.

 

I also do run a phosphate remover in my tank. I just changed the media in the reactor two days ago. Again, the media reactor has been running for a while now.

 

Two days ago when I checked my alk, after setting up my new Grey Seas calcium reactor, my alk was at 13. I am going to test it again today.

 

I am also on my third day of lights out to help irradicate my bryopsis. But again all these things either were running prior to the pH drop or after I noticed the drop.

 

I am thinking the most logical explaination for the initial drop is the a/c.

 

I did use a Seachem buffer and that has helped somewhat to keep my pH level at this point. I believe that once the lights come back on, over the next two days I will slowly add the lights again, the pH should go up.

 

I will keep you all posted.

[dhoch]

Rebecca:

 

Understanding what causes your pH to go up and down is critical and will help you diagnosis the problem... you have many things here which are contributing.

 

pH goes up because of lack of CO2 in the water, goes down with the presence of it.

 

As it relates to the a/c, yes it is running and I have an open vent right behind the fish tank in the fish room to keep the room and tank cooler. In our house, if the a/c is on, the windows are closed so the house is sealed so to speak.

 

So if a room (or house) is sealed off from the outside the amount of CO2 created by the inhabitants is increasing (not to harmful levels for us, but enough to do a pH drop)... watch your pH one time when you have 15-20 people downstairs looking at your tank... they are createing a lot of CO2 which will cause your ph to drop.

 

Yes, I dose Kalk with a kalk stirrer. I put in about a drop a second. It runs 24/7 but this has been running long before the pH drop.

 

I am also on my third day of lights out to help irradicate my bryopsis. But again all these things either were running prior to the pH drop or after I noticed the drop.

 

So what removes CO2 from your tank? Algae does!! Algae like trees takes in light and CO2 and converts it to O2...so when your lights are on ph rises.

 

Chemical reactions is one: Kalkwasser.... The Kalkwasser (and I'm not sure of the chemestry) causes a chemical reaction that uses up CO2 when it is added... this is why most people add at night (when the lights are off to help keep down the CO2 and the pH up)

 

Two days ago when I checked my alk, after setting up my new Grey Seas calcium reactor, my alk was at 13. I am going to test it again today.

 

Have you tested your effluant? ph of calcium reactors can have a signifigant effect on pH.

 

Overall I don't think it's one factor, but instead MANY.

 

Dave

[Gatortailale]

Probably a combination of things. I seem to recall from one of my conversations with copps that PH swings are not that harmful. Since I started in the hobby back in late 2000, my tanks have always had a .2 to .3 daily swing during the day. So far, all has been well in each system. The MAIN thing you want to avoid is ALK drops or big swings. Since your ALK is at 13, you should be fine. ALK below 8 is when problems start.

 

Now that you have your calcium reactor running, this first week is key to testing your ALK daily or every other day so you can tell 1) how much alk your tank & corals are using up and 2) whether you need to adjust your calcium reactor to add more or less ALK via effluent drip.

 

If you haven't read this article, I would advise you to read it now that you are running a calcium reactor because it IMO is the best article at explaining how the reactor works and how to make adjustments to it.

 

I found this a good read on how calcium reactor works & making adjustments

 

 

Calcium Carbonate Reactors

Sanjay Joshi: http://www.reefs.org/library/talklog/s_joshi_062997.html

 

 

Adjusting the Reactor (and some reactor Math)

Once you have decided to add a reactor, how do you go about adjusting it, i.e. determining the effluent flow rate and the amount of CO2 to be added.

 

The following discussion is based on several personal conversations with Dr. Craig Bingman, and the experience of several others in the Fishroom.

 

Let us assume that the reef system contains T liters of water. Set the CO2 flow rate to approx. 20-30 bubbles/min and the effluent flow rate to a slow enough drip and let the reactor run for several hours until it reaches a steady state. Measure the effluent flow rate in liters/hr - say its L liters/hr.

 

Now measure the alkalinity in the tank, and the alkalinity of the effluent. The difference between the two values will give you the increase in alkalinity due to the reactor. Let us say this is d meq/L.

 

Assuming no calcification and use of alkalinity, this will result in a an increase in tank alkalinity that is given by the following formula:

 

Increase in tank alk/day due to the reactor = (d x L x 24)/T - (1)

 

Now measure the tank alkalinity after a day. The difference between the increase in alkalinity due to the reactor and the actual increase in alkalinity will give you the daily consumption of alkalinity for your tank. Let us say this value is c meq/L.

 

So now we need to adjust the reactor so that the daily increase due to the reactor is approximately c meq/L. This will give us the setting at which the reactor will replenish the alkalinity that is consumed daily.

 

Looking at the equation (1), we can see that there are 2 ways in this can be achieved.

 

(1) adjusting d - the increase in effluent alkalinity

(2) increasing L - effluent flow rate

The effluent alkalinity can be increased by increasing the amount of CO2, and keeping the effluent flow rate constant. Increasing the flow rate will result in a decrease in effluent alkalinity if the CO2 flow rate is not simultaneously increased.

 

Which one of these is a better adjustment?. My opinion is that increasing the amount of CO2, and keeping the flow rate is a better choice, since it adds less CO2 to the tank.

 

Similarly to reduce the alkalinity of the effluent, it is better to reduce the amount of CO2 added.

 

I don't want to bore you all with the math and chemistry details but I feel that a basic understanding is necessary to avoid the trial and error, and test and adjust solutions. You can use the above equation to calculate, for example, what the value of d should be, given a certain effluent rate and the desired increase in alkalinity - rather than making wild guesses and adjustments.

[Guest Bemmer]

Craig,

Thanks for this information. If you don't mind I am going to cut and paste your comments to my "setup" thread in the members discussion. This is very good information for others to view as well.

 

Rebecca