pH fluctuations

[kriswaters]

Okay, what causes the pH to fluctuate so much? I do diligent weekly water changes, my parameters are all good...what is up? Does any one have any links to the relationship between "x" and pH?

 

Impur I think you went through this...I search for your threads but couldn't find them.

 

Kris

[andy]

It's normal for pH to swing in aquaria. During the day, photosynthesis consumes CO2 and increases dissolved oxygen, increasing pH. At night, the reverse -- oxygen is consumed and CO2 increases reducing pH as the water becomes more acidic (CO2 + water = carbonic acid. CO2 + water + sugar = Coca-cola (clap) ).

 

The oxygen/CO2 balance in the surrounding air also affects tank pH; I can look at my controller's pH logs and make a good guess as to whether people have been downstairs watching TV with the door closed... pH drops when they do, since there is more CO2 in the air from their respiration.

 

How much of a swing do you see? Does it vary by time of day?

 

Here are a few resources:

 

High pH: Causes and Cures

 

Low pH: Causes and Cures

 

The “How To” Guide to Reef Aquarium Chemistry for Beginners,

Part 3: pH

[pledosophy]

My pH stays at 8.3 all day (and night ) long. I use an inversly lit refugium. Use macro algaes. Have a good amount of surface aggitation. Run a skimmer (on two of the three tanks), and keep my windows cracked.

 

I had a CO2 problem at a place I lived in a few years back and it was not safe to leave the windows open so I put an airpump outside the window and ran the airline through the window and into the tank. Bringing fresh air in worked out great for me.

 

Keeping Ca, Mg, and Alk in line will help too.

 

HTH

 

JME

[impur]

I went thru low pH due to my CA reactor. I was not able to drive off the excess CO2 from the reactor. So i removed the reactor and added 2 tablespoons kalk to my auto topoff in addition to running the airline for my skimmer to an open window. Like Kevin said, bringing in outside, fresh air makes a big difference IMO. My pH now ranges from 8.3 at night to 8.6 daytime.

 

What is the low and high that your pH is getting to? How about your alk/calcium?

 

A nice test for you to do would be to take a bowl of tank water, an airstone and airpump, and place it outside for 30 min running. Test the pH before and after. I think you will find a large difference. This is because the airstone is driving off the excess CO2.

 

Usually the reason people have a low pH problem is due to excess CO2 in our houses. They make houses so airtight to help make them energy efficient and this doesn't leave anywhere for the CO2 to go. Your skimmer sucks it up, chops it and pushes it into the water. As a result, the pH of the water declines.

 

HTH and let us know how it goes!!

 

 

Miles

[kriswaters]

Thanks. It makes since. I leave the window cracked in the room, but the idea of running the line out is a good idea. I have been running on the low side 8.2 and such. My alk is been difficult to maintain as well...lately running at 2.5 to 3 meq/L despite Ca levels. I am due for a new test kit and wondering what you use?

 

I like the idea of the reverse light schedule on the fuge. I now have several tools to assist me in finding the problem!

 

Kris

[impur]

One other thing you can do is add an airstone to your WC water as its mixing. Thats one thing i did when i was using Oceanic salt with low pH. I would let it mix up next to a window and have the airpump outside pumping fresh air into my WC tub. I'd let it mix for 24-48 hours this way and it always brings up the pH.

 

 

But in the end i think you have a problem with that salt mix.

[andy]

A pH of 8.2 isn't bad. As far as test kits, I just switched from Salifert to Elos and am really happy with the new kits.

[kriswaters]

Thanks for the advice. I would really like to dial in the chemistry in my tank. There is sooo much information out there...hmmm

 

Well, we will see how we can get things together.

 

Kris

[pledosophy]

I use a monitor for pH. It saves money in the long run. I think I paid $50 for it and it has lasted me a year. I used to test three time a week. (I like testing stuff).

 

If my pH is off I look to Ca, Alk, and Mg. If those are in line then my pH will be unless the issue is C02 or lack of surface exchange. JME

 

For my other test kits I use salifert but have a Red Sea Mg test kit as the Saliferts were hard to come by for a bit. I need to get a new one but have been lazy lately.

 

I have never used a CA reactor, my tanks are running O.K. on 2 part but I'm not keeping more then a few SPS frags ATM.

 

JME.