Barr GH Booster makes water acidic?

[rusticitas]

I have a confusing situation. I have been using the Barr GH Booster for several months now, since my Equilibrium ran out, and I just pulled out my long-neglected pH/TDS/Cond meter, calibrated it (pH 7.01) and started to take some measurements of various tanks (low/high tech planted, killie tanks, greenwater, daphnids, everything.)

I was shocked that many of my tanks were very acidic! My main planted tank, a 20-long, was at pH 5.5! The only one that was above pH 7 was the greenwater which I typically add CaCO3 or Seachem's Alkaline Buffer to the water when starting a new batch.

My city's tap water is typically pH 6.8-7.0, 27-30 µS cond., and 25-30 ppm TDS. So, very soft water.

Please note:

1. My planted tanks water is changed from my kitchen tap using a Python. Once refilled, I add Barr GH Booster.
   
2. My other tanks (killies, etc) are changed as needed, by hand, one gallon at a time, from a 20 gallon container of "aged" tap water which is taken from tap. I keep a heater and use a pump to circulate for a day before using.
   
3. Additionally, I have a "hard water" premix in a 5 gallon bucket which is tap water well mixed with 4g of Barr GH Booster. I do this so I can mix this "hard water" premix with the water from the previous "aged" water to make the water harder for various killie and other tanks.
   

Once I saw the pH was so low, I measured a newly made batch of "aged tap water" and "hard water premix". The "aged tap water" was pH 6.8. The "hard water premix" was pH 4.5!

So, this would seem to explain why the killie tanks with more "hard water premix" were more acidic than others.

Why does the water go so acidic from the Barr GH Booster?

Is the low pH a "bad" thing for planted tanks? (Ignore the killies here, will ask killietalk mailing list about that.)

-Jason

 

[rusticitas]

I am guessing that this is why I keep having intermittent, bad problems with BBA. Especially when I do a water change and hook up a new CO2 cannister. When I hook up a new cannister, I seem to frequently mess up something and I have to dial in all the pressure settings again, so CO2 is either high or low at first if I can't stick around to keep an eye on it for a few hours afterwards...

 

[Carissa]

If your pH after injecting co2 is 5.5, the degassed pH is probably around 6.5 - 6.7, not too bad. It would be normal for tap water that has near 0 KH (like mine), if you are not adding anything to boost KH or anything that would be leaching KH into the tank to cause it to rise. Another issue that could crop up in low KH tanks is that if you're not removing enough of the waste from the substrate, or doing lots of water changes, whatever builds up causes the water to go acidic over time (say within a month of no water changes, or less depending on fish load). I know this doesn't answer your question, but the main reason for your low pH may have little to do with the GH booster.

As far as whether low pH is bad or not.... the general consensus seems to be that it's ok. My co2 tank has a pH probably down in the high 5's or at least low 6's and everyone seems happy, fish and plants.

 

[rusticitas]

I should have added that there are 3 planted tanks: 2 are using pressurized CO2, 1 is not (lower-light, but use Excel). I use EI all all three, and do weekly 50% water changes.

Actually, it's the "lower-light" tank (15 gallon) that had the lowest pH! And I add the same amount of GH Booster, proportionally that is, to each tank after the water change.

And I think the telling aspect was that in the "hard water premix" (5 gallon tap water + 4 grams of Barr GH Booster) the pH is down around pH ~4.5.

 

[Dusko]

This is an interesting case. Can you tell me what is your GH and KH, in ppm please (tap and tanks).

I can't remember last time I have checked the pH... but I do test for GH and KH occasionally, which is in my opinion the important part of buffering the systems pH and binding acids.

My tap is also way too soft, and for that reason I added a fair amount of CaCO3 (couldn't find any Dolomite) into my soils (2 new tank), so they don't get too acidic over time.
Beside that I will also dose the GH-Booster every week.

Regards, Dusko

 

[Carissa]

Ok, in that case, that sounds very odd. If the co2 tanks are at or above 5.5, that sounds normal if you have low KH. But in a non-co2 tank, 5.5 is pretty acidic. GH itself has no effect on pH, it's only the KH that buffers the pH. I add magnesium sulfate and calcium chloride to my tanks, it only increases GH and never affects pH. I'm not sure what else might be in the GH booster that would cause a pH drop.

 

[aquabillpers]

My impression is that GH Booster (or Equilibrium) does not effect alkalinity (KH). I know that when I use Equilibrium I have to add Epsom salts to increase alkalinity.

If the above is correct, it's unlikely that GH Booster would have any effect on pH, since at any time that is closely related to the alkalinity level.

But I could be wrong, too.

Bill

 

[Carissa]

Even if it were adding KH, that would only bring pH up, not down. Does anyone have the ingredients list?

Also....epsom salts don't increase KH either. KH is carbonates - i.e. calcium carbonate, sodium bicarbonate, etc. would increase it and possibly affect pH (bringing it up). Epsom salts is magnesium sulfate. The magnesium adds GH since GH measures magnesium and calcium only.

 

[Tom Barr]

CaSO4
MgSO4
FeSO4
MnSO4
K2SO4

See anything that alters pH?


Regards,
Tom Barr

 

[VaughnH]

Is there a chance that the pH probe calibration was faulty? For example, to be a good calibration you need two different pH solutions, usually 4.01 and 7.01, as I recall. It is only if you can assume the probe is working correctly and just want to adjust the meter reading, that you can get by with the single point calibration.

 

[CATFISH mick]

CaSO4
MgSO4
FeSO4
MnSO4
K2SO4

See anything that alters pH?


Regards,
Tom Barr

Ummmmmm Sulphur or in the case above sulphates

Do I win a prize Tom??

Great site and info by the way.

 

[Carissa]

How would the sulfates react in water to produce an acid?

 

[CATFISH mick]

The same way sulphur applied to soil will lower the ph of that soil with the aid of bacteria and moisture to form sulphuric acid. it can take quite some time for this to happen though. Aluminium sulphate would lower the water alot quicker if it were used.

 

[rusticitas]

Tom,

(Please know that I am not criticizing GH Booster!)

That's the queer thing. Nothing in GH Booster, as far as I understand chemistry, should affect pH. Which is why I am scratching my head over this one. And at this point I do not at all recall what the water was like using Seachem's Equilibrium. I have not been scientific about it up to this point. No baseline. (I know, Tom, smacking my own hands...)

I'm fairly confident in the meter's readings, however, as my city's tap water is quite consistent, and the readings were pretty much as I remember them always being. From memory, typically just about pH 6.9 (+/- ~0.1) , TDS is something like 60 ppm (+/- 10), and conductivity (I think) was around 30-50. Sorry I'm not exact, but I'm away from home for the next couple of days. And when I saw the one planted tank was pH ~5.5, I immediately tested some tap water which had the readings I expected.

I have for awhile now just done the weekly 50% water changes from the tap on the planted tanks using the Python, then dechlorinated and added GH Booster and KNO3 + KH2PO4.

I have also for awhile been keeping a container of "aged", dechlorinated, tap water (20 gallons) and a sidekick small container (5 gallons) of "aged" dechlorinated tap water with 4g of GH Booster mixed in. As stated before, I use this sidekick mixture to combine with the "aged" straight tap water to "harden" as needed for my killie tanks. (By "aged" I simply mean the water has been in a container with a small pump for circulation and a heater and it has outgassed by the time I get around to using it.)

As it seems all tanks that have some water with GH Booster in it have gone quite acidic. I will see if I can get some pH 4.01 calibration fluid to use with the 7.01 to calibrate my meter upon my return home and test again.

• What the heck is my next step?
• Could I have a "bad" batch of GH Booster?
• Should I get some Equilibrium and test?
• Should I just add CaCO3 to offset this effect? If so, how much per n gallons of water?

-Jason

 

[Carissa]

I don't know enough about chemistry to understand it, but perhaps with very large concentrations of SO4 in water, sulphuric acid is produced? I'm wondering if the GH booster was dosed without premixing and allowing it to sit at high concentrations, if there would be a difference. I dose magnesium sulfate and K2SO4 in my tanks and have never noticed a pH drop from the sulfates (and I have little to no buffer in my water). But I dose straight powder, and in small doses compared to what you added to your premix. I wonder if you were to take a quantity of water (aged) and dose what would be considered a "normal" amount assuming it was a tank, and test pH before and after, if there would be a difference? If not, something is happening in that premix that's not happening normally, or that wouldn't happen if you dosed straight powder.

 

[Carissa]

I just did a little experiment of my own. I had three test tubes, filled them all with tap water (which for me is close to distilled,

 

[Tom Barr]

K2SO4, CaSO4 and MgSO4 should not alter pH.
Their by products may.........if they have any contaminants etc also.

Not that pH really has a lot of meaning since we add CO2 and are more concerned with KH and Ca and Mg.............

In soil, or where there might be strong reducing anaerobic conditions, SO4's=> H2S etc, but many acids can be produced under strong reduction.

In plain sterile tap, this should not be the case.
Most tap water is loaded with SO4.......

Regards,
Tom Barr

 

[CATFISH mick]

K2SO4, CaSO4 and MgSO4 should not alter pH.
Their by products may.........if they have any contaminants etc also.

Not that pH really has a lot of meaning since we add CO2 and are more concerned with KH and Ca and Mg.............

In soil, or where there might be strong reducing anaerobic conditions, SO4's=> H2S etc, but many acids can be produced under strong reduction.

In plain sterile tap, this should not be the case.
Most tap water is loaded with SO4.......

Regards,
Tom Barr

K2so4 should not alter ph but mgso4 can raise it and caco3 can in fact lower ph by the way of 'mopping up' hydrogen ions - no more, no less! There are a variety of ways to do this which can include calcium/lime - but it is certainly not limited to this.

Lime (CaCO3 - calcium carbonate) mops up hydrogen the following way:

CaCO3 + 2H+ → Ca2+ + H2O + CO2

But magnesium carbonate (with no calcium) can be just as effective:

MgCO3 + 2H+ → Mg2+ + H2O + CO2

Hydrogen is a highly reactive/aggressive cation capable of stripping other cations from their bonded anionic partners, e.g. (CO3)2-. Calcium, magnesium and other cations are merely passive passengers in the process of raising pH - it is their anionic partners that actually do the 'mopping up'.

Some unexpected results can occur though. For example, calcium sulphate (CaSO4) found in gypsum can react the following way in the presence of excess hydrogen:

CaSO4 + 2H+ → Ca2+ + H2SO4 + CO2

H2SO4 is sulphuric acid!! Therefore adding sulphate-based inputs (even with a calcium component) to acidic water can plummet pH levels down even further.


to adjust kh or alkalinity use bi-carb soda

to adjust gh and kh use calcium carbonate

 

[Tom Barr]

K2so4 should not alter ph but mgso4 can raise it and caco3 can in fact lower ph by the way of 'mopping up' hydrogen ions - no more, no less! There are a variety of ways to do this which can include calcium/lime - but it is certainly not limited to this.

Lime (CaCO3 - calcium carbonate) mops up hydrogen the following way:

CaCO3 + 2H+ → Ca2+ + H2O + CO2

But magnesium carbonate (with no calcium) can be just as effective:

MgCO3 + 2H+ → Mg2+ + H2O + CO2

Hydrogen is a highly reactive/aggressive cation capable of stripping other cations from their bonded anionic partners, e.g. (CO3)2-. Calcium, magnesium and other cations are merely passive passengers in the process of raising pH - it is their anionic partners that actually do the 'mopping up'.

Some unexpected results can occur though. For example, calcium sulphate (CaSO4) found in gypsum can react the following way in the presence of excess hydrogen:

CaSO4 + 2H+ → Ca2+ + H2SO4 + CO2

H2SO4 is sulphuric acid!! Therefore adding sulphate-based inputs (even with a calcium component) to acidic water can plummet pH levels down even further.


to adjust kh or alkalinity use bi-carb soda

to adjust gh and kh use calcium carbonate

Adding the salts alone I mentioned salts will not change the pH at equilibrium. If you add excess H+'s, well........of course that will change the pH, you are adding excess H+'s..........so the pH will move....

Yes, a small amount depending on how much H+'s you add will form H2SO4.
But not unless you add those H+'s.........

You can make the same exact argument for NaCl and adding H+'s.........CaCl2 + H2O + H+'s-> Ca+ HCL............

Add it and see.
Add NaCl.
Add KCl
MgCl2

Put another way, what happens if you add lime as Ca(OH)2 (basic) and H2SO4(acid)?

CaSO4 + 2H2O.........

HCL + NaOH = NaCl + H2O........
Strong acid + strong base to give neutral solution (H2O + salt)

pH of saturated CaSO4 solution is almost perfectly neutral (7.06). Same with MgSO4, except it's slightly acidic: look, here's the MSDS on it:

MAGNESIUM SULFATE
http://www.hillbrothers.com/msds/pdf/n/magnesium-sulfate.pdf

pH is 6.5~7
Neutral which is what a typical neutral salt should produce.
magnesium + sulphuric acid ==> magnesium sulphate + hydrogen

Mg(s) + H2SO4(aq) ==> MgSO4(aq) + H2(g)
Sulphuric acid gives sulphate salt and hydrogen.

pH, ACIDS, BASES and SALTS Revision Notes for GCSE-IGCSE-KS4 courses at Doc Brown's Chemistry Clinic. for revising AQA OCR Edexcel CIE WJEC CCEA revising for science-chemistry exams-examinations docbacidsbasessalts)

I'm not quite sure where folks are getting mixed up here.
Too much google and not enough Chemistry I thinks.



Regards,
Tom Barr

 

[Carissa]

I'm not a chemistry buff whatsoever, but I try to learn... this is probably oversimplifying it but I have to start somewhere.

So if there are extra H+ kicking around anyway, isn't the water already by definition acidic? Would the reaction of the excess H+ with the other things somehow make the water more acidic than it already was before? If so, don't more H+'s have to be coming from somewhere? How can more H+ be around to lower pH if we don't add any more H? Is this what you're saying Tom?

In my little experiment, the KH2PO4 made the water more acidic. I see an H there in the equation so this must have ultimately caused it in some way, right? The Plantex CSM+B did too, but I don't know the ingredients of this. The K2SO4 did nothing....because I wasn't adding any H? My understanding of this is far from complete....it's been way too long since chemistry class.