Ca/Alk imbalance vs. pH....

[MikeS]

Hi all...

Trying to answer a question for a member of another forum....

is it possible for a Ca/Alk imbalance to create a low pH problem? The member has a 470ppm Ca level @ 3.2 meq/L Alk. At 470ppm Ca, balance is around 5.5 meq/L Alk. His pH is at 7.8. He says there should be no real gas exchange issues in his tank, and his setup discription leads me to believe the same.

I will of course give full credit to those who answer, I'm asking because I suspect this is case, but I really don't know the answer....

MikeS

 

[DonW]

Any Idea what mg is?

Don

 

[MikeS]

no, I didn't ask him....

He's using Oceanic salt in a low Ca usage tank (mostly softies-new setup) so I bet it's high...


MikeS

 

[cwcross]

The imbalance itself between Ca and Alk won't cause a low pH issue. However, low alk can. Everything depends upon the buffering system in the salt. If the salt is good, then pH should be about 8.2-8.4 with no adjustments. Then just alk can by used to help keep pH constant.

His alk is definitely low and out of balance. This will make it easier for acids to take the pH down than if alk is high.

If Mg, is low, then it becomes difficult to keep Ca and Alk in balance and you will possibly notice some precipitated lime in the system, like on heaters and PH's and such. This can in principle make it difficult to keep alk up and thus causes pH variations to be more problematic.

High CO2 in the house via a gas furnace can also cause a pH downward presssure. Also addition of partially uncured LR. Also, some other source of acid buildup in the system.

I suggest he drip some Baking Soda into the system to get the alk up.

Sincerely...Collin

Hi all...

Trying to answer a question for a member of another forum....

is it possible for a Ca/Alk imbalance to create a low pH problem? The member has a 470ppm Ca level @ 3.2 meq/L Alk. At 470ppm Ca, balance is around 5.5 meq/L Alk. His pH is at 7.8. He says there should be no real gas exchange issues in his tank, and his setup discription leads me to believe the same.

I will of course give full credit to those who answer, I'm asking because I suspect this is case, but I really don't know the answer....

MikeS

 

[MikeS]

Thanks!

MikeS

 

[j.stagner]

High CO2 in the house via a gas furnace can also cause a pH downward presssure.

So, is this CO2 problem going to persist throughout the house, and how the heck do you resolve that?

Also, I've currently got my 75g in the garage, which is of course where the gas furnace is.... And I've got a pH that just seems to hover around 8.0 despite the dosing of kalk. Can these be related?

 

[DonW]

So, is this CO2 problem going to persist throughout the house, and how the heck do you resolve that?

Also, I've currently got my 75g in the garage, which is of course where the gas furnace is.... And I've got a pH that just seems to hover around 8.0 despite the dosing of kalk. Can these be related?

You could run your skimmer air line outside, fans help a little, whole house exaust fans for extreme problems. Bathroom exhaust fans are ok to.

Don

 

[Curtswearing]

You could run your skimmer air line outside, fans help a little, whole house exaust fans for extreme problems. Bathroom exhaust fans are ok to.Don

Great point Don. You can also make an air scrubber for your tank. Get a couple foot long piece of 3" tubing. Fill the ends up with aquarium filter fluff and put some GAC in the middle. You'll have to experiment on how much GAC you add so that you don't impede airflow too much. You'll need a cap on one end that is drilled to the size of the air intake hose for your skimmer and this should be siliconed to the cap. (Don't seal the cap because you'll want to replace the media monthly).

It's not always related to CO2 though. Sometimes your skimmer needs to be cleaned (or it is too small for your bioload). Excess organics and associated bacteria depress pH.

 

[j.stagner]

I'll try to get some tubing and see if running the line outside helps, though I wonder about the length. In order to reach outside, the line will need to be at least 10 feet long. I'm renting, so I cannot put holes in the wall. Do you think that'll be too long?

I'm running a custom MR-1 from MyReefCreations, using a Dolphin DP2000 to power it, so I think it should have a pretty decent amount of pull on the airline, but I guess I won't know till I try, huh?

As for cleaning the skimmer, that almost always needs to be done This thing builds up a pretty thick layer of gunk on the riser tube in short order, so I really should clean it more than once a week, but never seem to actually do so.

Thanks for the input folks.

 

[NaH2O]

j.stagner - if you are having low pH issues, a good way to know if it is due to excess CO2 in the house, is to take a sample of water outside for a bit, then test the pH. Also, you can take a sample and stick an airstone in it and see if the pH makes significant changes.

 

[fishman]

I can't seem to keep my PH above 8.0. I add 6L of Kalawasser every day. I get the Precipitated lime build up badly. I use Kent salt. Should I add a drip of baking soda. How much per Liter or Gallon(of freshwater added)?

The imbalance itself between Ca and Alk won't cause a low pH issue. However, low alk can. Everything depends upon the buffering system in the salt. If the salt is good, then pH should be about 8.2-8.4 with no adjustments. Then just alk can by used to help keep pH constant.



If Mg, is low, then it becomes difficult to keep Ca and Alk in balance and you will possibly notice some precipitated lime in the system, like on heaters and PH's and such. This can in principle make it difficult to keep alk up and thus causes pH variations to be more problematic.



I suggest he drip some Baking Soda into the system to get the alk up.

Sincerely...Collin

 

[cwcross]

In my mind you have one of three problems or a combination of them all.

1.) Too high of CO2 in your house. Check this by putting a water sample outside for 24 hours and watching the pH. If it rises then this is at least part of your problem.

2.) You are really out of balance in water params, most likely low in Mg etc.

To solve this problem you need to work to re-establish the balance of your tank. I suggest first to do about 5 20% water changes over the next month. This will re-boot your system so to speak. During this time, you might want to consider changing salt's depending upon what you use. That or at least get a new batch. After this is done, your Mg levels and balance in general should be largely re-established.

3.) You have organic acids being produced. This is harder to solve. You will need more effective skimming, lower feeding, watch alk closely and adjust as needed.

Beyond that I do not suggest the use of any buffer that contains borate. Use Kalk (pickling lime) as a primary source of Ca and Alk boosting. Beyond this supplement with either a Ca reactor or a 2-part that doesn't contain borate.

Hope this helps...Collin

 

[fishman]

I wonder if it's my PH monitor. It is made by Hanna. It says that it automaticaly compesates for tempurature? When I test with color change test kit I get 8.4. When I test with my Electric PH monitor I get 7.9? I've calibrated it several times.

Water changes lower my PH because my fresh mixed salt water (Kent) has a PH of 7.8.

 

[cwcross]

Have you calibrated your pH meter lately? You should calibrate it at low and high pH standards if it can take a two point curve. Elsewise calibrate it near pH 8-8.5.

I doubt the temperature compensation is the cause. I don't think this would account for a 0.5 unit shift as you are describing. Between the two, I would tend to go with the colorimetric test. This sounds like it could be your problem. However, it is still strange that you are precipitating lime in your tank. What is your Ca level and alk level?

 

[cwcross]

Water changes lower my PH because my fresh mixed salt water (Kent) has a PH of 7.8.

Also, if your salt has a buffer system at pH 7.8, your tank will always trend in that direction. You can boost it with alk booster but when it gets used by your corals, it will tend to fall back down.

Collin

 

[fishman]

I think I've been overdosing Lime water wich has caused the percipitate. Trying to increase the PH. I going to go buy a decent color change test for PH and Ca. I can't find my color card for my alk test. My 3 year old daughter loved the purple colors on that card, humm!

 

[fishman]

I think I've been overdosing Lime water wich has caused the percipitate. Trying to increase the PH. I going to go buy a decent color change test for PH and Ca. I can't find my color card for my alk test. My 3 year old daughter loved the purple colors on that card, humm! :?:

Everyone I have talked to says they have never had a PH problem with Kent. The PH monitor is set up to calabrate at 7.01 and 4.01. You can calibrate at one or both. I have always just used 7.01.

 

[NaH2O]

Another thing to remember with the pH monitors, at least with the Pinpoint, is the temperature of the solution determines the calibration number. So, look at the calibration fluid and make sure you have the correct temperature (the ones I use it is listed on the back of the package) before calibrating. You can then compare to your color change test kit.

 

[fishman]

Yah, that was another thing I was thinking about. It says as close to 77 deg. as possible. I'm usually about 75 deg.

 

[MDMAquatic]

Ok, i cannot believe what i have just read, i know i'm new to this forum, and i am not trying to make waves, but do you all really think that Co2 from a furnace or heater in your house is going to make a PH change in your tank?? Get real....i am a certified hazmat specialist and first responder, and so i know a little about Co2 buildup, first of all if it WAS to get to a level that would cause a change it would hang in the lowest place of the house and next to the floor. Second for it to make a change in ph it would have to reduce the oxygen contenet in the house to less than 18.5% You would be sick at that point. A properly operating furnace should not be adding anything to the air anyways...they are vented and the new high efficient ones have very little c02 regardless. I just don't buy it without some hard data. This guy has a low alk problem allowing the natural tendency of the water to go acid move in that direction. Get the Alk up and it'll probably stabilize out. Just my 2 cents