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

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...

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.

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.

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

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.

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. <g>

Bill

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.

CaSO4
MgSO4
FeSO4
MnSO4
K2SO4

See anything that alters pH?


Regards,
Tom Barr

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.