Huge drop in Alkalinity

Randy Holmes-Farley

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understood. I will get a another test kit and check. Thank you @90's reefer

I was about to say that the answer to any chemistry issue that starts with the word "Huge" is likely test error. lol

That said, the history before the alk drop would be important to know.

If you were adding 3 dKH per day every day and suddenly stopped, and saw that alk drop, its expected.

If your tank alk has been stable for months and suddenly one day drops multiple dKH in a day, that's either test error, or someone pouring acid into your tank.
 
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navidreef

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I was about to say that the answer to any chemistry issue that starts with the word "Huge" is likely test error. lol

That said, the history before the alk drop would be important to know.

If you were adding 3 dKH per day every day and suddenly stopped, and saw that alk drop, its expected.

If your tank alk has been stable for months and suddenly one day drops multiple dKH in a day, that's either test error, or someone pouring acid into your tank.
Hi Randy, I don't think it is cause when i test my PH my PH drops around 2 points every 24 hour. I put a air stone into my sump which draws air from the outside of my house.
 

Uncle99

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Uncle is that a typo lol? Ur daily is only 0.05 dkh per day? I thought I remember randy saying at one point that a tank, esp a well-stocked reef, is about 0.5 dkh to up to 4 dkh daily. Mine is pretty well stocked too and does 1.5 dkh per day. Mag is at 1350 so probably not a lot of precipitation, i also dont see visual signs of precipitation either.
Excellent catch....yup....1/2 a DKH per day......so 0.5dkh.
Thanks for the correction.
 
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navidreef

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I was about to say that the answer to any chemistry issue that starts with the word "Huge" is likely test error. lol

That said, the history before the alk drop would be important to know.

If you were adding 3 dKH per day every day and suddenly stopped, and saw that alk drop, its expected.

If your tank alk has been stable for months and suddenly one day drops multiple dKH in a day, that's either test error, or someone pouring acid into your tank.
Could it be the number of fishes that I have you think? Test kit is fine I tested on fresh RODI
 
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navidreef

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They breath out CO2 which lowers PH and subsequently lowers alk isn’t that the case
 

Randy Holmes-Farley

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They breath out CO2 which lowers PH and subsequently lowers alk isn’t that the case

No.

No amount of CO2 added to, or removed from, seawater has any impact at all on alkalinity.

Yes, it does alter pH.


Alkalinity Facts​

There are several facts about total alkalinity that follow directly from the definition. Unfortunately, some of these have been misunderstood by some hobby authors.

One of these facts is termed The Principle of Conservation of Alkalinity by Pankow (“Aquatic Chemistry Concepts”, 1991). He shows mathematically that the total alkalinity of a sample CANNOT be changed by adding or subtracting CO2. Unfortunately, there is an article available on line, which claims otherwise, and encourages people to “lower alkalinity” by adding CO2 in the form of seltzer water. This is simply incorrect.

Forgetting the math for the moment, it is easy to see how this must be the case. If carbonic acid is added to any aqueous sample with a measurable alkalinity, what can happen?

Well, the carbonic acid can release protons by reversing equations 1 and 2:

(5) H2CO3 ==> H+ + HCO3–

(6) HCO3– ==> H+ + CO3—

These protons can go on to reduce alkalinity by combining with something that is in the sample that provides alkalinity (carbonate, bicarbonate, borate, phosphate, etc). However, for every proton that leaves the carbonic acid and reduces alkalinity, a new bicarbonate or carbonate ion is formed that adds to alkalinity, and the net change in total alkalinity is exactly zero. The pH will change, and the speciation of the things contributing to alkalinity will change, but not the total alkalinity.

This is not true for strong acids, however. If you add hydrochloric, sulfuric or phosphoric acids (or any acid with a pKa lower than the carbonic acid endpoint), there will be a reduction in the alkalinity.
 
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navidreef

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Guys some update

I took a sample of my water to my LFS and they. Tested and gave me a dKH of 6 which proves my test kit was fine all along

there are white coating all over my heater sump return pump gear . What does that mean ? No matter how much soda ash I dose level never rises past 7 dKH
 

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Guys some update

I took a sample of my water to my LFS and they. Tested and gave me a dKH of 6 which proves my test kit was fine all along

there are white coating all over my heater sump return pump gear . What does that mean ? No matter how much soda ash I dose level never rises past 7 dKH
That's abiotic precipitation

Usually that's a problem in high alk high ca high ph low mag situations

Something is off here...;Bored
 

Rmckoy

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Rather chasing numbers to achieve “ proper “ parameters.
is it stable ?
Water changes help correct high or low numbers and more frequent water changes can help with stability .
The fact that you’re only changing water when nitrates reach a goal value .
try more frequent ?
See if that corrects the issue .

As long as cal , alk , mag , salinity , ph and temp are all stable and not having huge swings daily is the most important
 

Randy Holmes-Farley

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Guys some update

I took a sample of my water to my LFS and they. Tested and gave me a dKH of 6 which proves my test kit was fine all along

there are white coating all over my heater sump return pump gear . What does that mean ? No matter how much soda ash I dose level never rises past 7 dKH

To avoid precipitation, stop using soda ash, and stop doing anything to raise pH (outside air, CO2 scrubber, etc.)

Stop all dosing for a few days, then when you resume, use baking soda for alkalinity, and do not try to push it past 7 dKH for a while at least.

Dissolve it in more water than before, and add it more slowly to as high flow area as you can find.
 
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navidreef

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To avoid precipitation, stop using soda ash, and stop doing anything to raise pH (outside air, CO2 scrubber, etc.)

Stop all dosing for a few days, then when you resume, use baking soda for alkalinity, and do not try to push it past 7 dKH for a while at least.

Dissolve it in more water than before, and add it more slowly to as high flow area as you can find.
Baking soda you mean sodium bicarbonate correct ?
Thank you for the advise will do and update
 
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