Understanding Reef Chemistry...

[Dom]

Here it is...

I just completed reading "Reef Aquarium Chemistry for Beginners". While I have clarification on some questions, I think I have more now than when I started. For example...

I understood that dosing with baking soda would raise pH. I took 1000ml of RO/DI water and added 15g of baking soda. Stirred well and then added two 200ml doses, 15 minutes apart. The baking soda solution initially drove the pH down and then came back up to where it started prior to the dose.

Isn't the opposite supposed to happen?

 

[Flippers4pups]

Dosing baking soda is primarily used to raise alkalinity, not raise ph. The rise of PH and drop is expected after dosing and equalize depending on the amount of dissolved co2 and carbonate.

 

[Dom]

Dosing baking soda is primarily used to raise alkalinity, not raise ph. The rise of PH and drop is expected after dosing and equalize depending on the amount of dissolved co2 and carbonate.

I look at pH as a horizontal line where acidity is at the extreme left and alkaline is at the extreme right. I understood baking soda to be a base, which to me means that when you add baking soda, you're reducing acidity. Reduced acidity means more alkalinity or higher pH.

 

[Flippers4pups]

Read this: http://www.advancedaquarist.com/2002/5/chemistry

 

[Flippers4pups]

And .....http://www.reefkeeping.com/issues/2004-09/rhf/

What is your ph at?

 

[Dom]

Currently I'm at 8.15, which is okay. But I'm in the middle of my light on cycle. When my lights are off, I'm down around 7.9, which isn't terrible. But there was a time when I'd be at 8.15 with lights out, so it seems pretty clear to me that my pH is trending downward. I was buffering my water changes, but I stopped doing that because I was having issues getting my calcium up (I have little no frag growth). It was suggested that the buffering was causing my low calcium.

 

[Dom]

Read this: http://www.advancedaquarist.com/2002/5/chemistry

I'm just starting to read this. It's like Russian alphabet soup; lots of letters, I can't read any of them.

This is the problem; there isn't any "plain English" explanations on the subject.

 

[Flippers4pups]

Ph between 7.8-8.5 is acceptable. Don't chase ph if within this range.

 

[Flippers4pups]

More basic....http://reefkeeping.com/issues/2004-05/rhf/

 

[Dom]

Ph between 7.8-8.5 is acceptable. Don't chase ph if within this range.

Okay... but I am concerned by the downward trend. I'd like to have a plan; I don't want to wait for it to get "too low". I'm trying to be pro-active.

 

[Flippers4pups]

Excessive co2 in your homes air can and will drive down ph do to respiration of the occupants in your home. Something simple as opening a window can substantially raise your ph. This is difficult to do in winter and summer months. Water surface agitation in your tank can help release co2 from your water. Some people run an airline from their skimmer intake to the outside of their home to bring in fresh air/ oxygen into the water, thus forcing out co2. Other ways are use of soda lime in form of a scrubber in line with a skimmers intake airline. Soda lime captures co2.

 

[Dom]

Excessive co2 in your homes air can and will drive down ph do to respiration of the occupants in your home. Something simple as opening a window can substantially raise your ph. This is difficult to do in winter and summer months. Water surface agitation in your tank can help release co2 from your water. Some people run an airline from their skimmer intake to the outside of their home to bring in fresh air/ oxygen into the water, thus forcing out co2. Other ways are use of soda lime in form of a scrubber in line with a skimmers intake airline. Soda lime captures co2.

I am running an air stone in the sump, and it did cause a small rise in pH. Also, I have a room fan circulating air.

 

[71xlch]

Worrying about pH is the last thing I worry about. You really have to mess up to get it out of range. I wouldn't label what you see as a trend. Maybe over 3-4 weeks of continuided dropping. Your tank will find a spot to settle and just leave it be. Worry about alk, cal, mag in that order. Don't chase numbers

 

[Flippers4pups]

I am running an air stone in the sump, and it did cause a small rise in pH. Also, I have a room fan circulating air.

Once again, don't chase ph.

Equilibrium will happen between water and air in an enclosed environment when concerned about co2. Sometimes running an air stone/ water agitation, with a closed house will not change ph. That's why fresh air only helps.

Once again, your ph is well within acceptable limits. Monitor/ test all your parameters frequently and keep a log of the results and dose accordingly.

Good luck and happy reefing!

 

[Dom]

Don't mean to beat this subject to death, but I have to say, I think pH is important because it effects so many other important parameters.

 

[jaws789832]

Whats your alkalinity at? To understand it better I dont use the term alkaline. I prefer base. From what I under stand alkalinity and ph (even though they are related) are 2 different things. Ph is the potential of hydrogen which makes things either acidic or basic depending how many ions of hydrogen and OH are in a solution. If there are more h ions then its acidic and if there are more oh ions its basic. Alkalinity is the buffering capacity of a solution as in the ability to resist changes to ph. If you take 2 glasses of water with a ph of 7, one with a alkalinity of 0 and the other with a high alkalinity and pour some acid in them both, the one with 0 alkalinity will drop in ph and stay there and the one with high alkalinity will probably initially drop but then raise back up to 7. If your ph is swinging, and your calcium is off, it is probably an alkalinity problem

 

[saltyfilmfolks]

Don't mean to beat this subject to death, but I have to say, I think pH is important because it effects so many other important parameters.

understanding it IS important. chasing it is not.
Ph is also the Result of other parameters.

you got this.

 

[Myka]

I understood that dosing with baking soda would raise pH. I took 1000ml of RO/DI water and added 15g of baking soda. Stirred well and then added two 200ml doses, 15 minutes apart. The baking soda solution initially drove the pH down and then came back up to where it started prior to the dose.

Isn't the opposite supposed to happen?

That's what sodium bicarbonate does. Try your experiment with sodium carbonate (baked baking soda) and you will see the opposite effect.

Either way, dosing carbonate or bicarbonate has only a temporary effect on pH as these other guys have explained.

 

[Myka]

Okay... but I am concerned by the downward trend. I'd like to have a plan; I don't want to wait for it to get "too low". I'm trying to be pro-active.

Consider dosing kalkwasser at night which is very high pH and will supplement both calcium and alkalinity for you.

 

[Sabellafella]

Here it is...

I just completed reading "Reef Aquarium Chemistry for Beginners". While I have clarification on some questions, I think I have more now than when I started. For example...

I understood that dosing with baking soda would raise pH. I took 1000ml of RO/DI water and added 15g of baking soda. Stirred well and then added two 200ml doses, 15 minutes apart. The baking soda solution initially drove the pH down and then came back up to where it started prior to the dose.

Isn't the opposite supposed to happen?

Did you bake the baking soda in the oven first?