Sodium Percarbonate instead of Baquacil oxidizer

SBell

New member
Sep 8, 2018
2
Sonoma Ca
#1
I have a 15000 gallon pool, that is using the Baquacil. I was wondering if It's possible to substitute Sodium Percarbonate instead of Baquacil oxidizer (27% H2O2), since it in much cheaper. If so how much would be the equivalent of 1 gallon of Baquacil oxidizer?
 

Donldson

TFP Expert
LifeTime Supporter
In The Industry
Jun 12, 2009
3,287
NW Ohio
#2
Welcome to TFP!

No, sodium percarbonate breaks down the Baquacil Sanitizer. It is actually commonly used (outside TFP) to assist with removing the sanitizer in preparation for converting to chlorine.

You will have to stick with peroxide as an oxidizer. If you are looking for something less costly our standard response is switching to chlorine. A TFP chlorine pool is far different from the average chlorine pool in comfort, cost, and clarity. But if you are happy with Baquacil then peroxide is the only option for an oxidizer.
 

SBell

New member
Sep 8, 2018
2
Sonoma Ca
#3
Welcome to TFP!

No, sodium percarbonate breaks down the Baquacil Sanitizer. It is actually commonly used (outside TFP) to assist with removing the sanitizer in preparation for converting to chlorine.

You will have to stick with peroxide as an oxidizer.
How exactly does that work? Sodium percarbonate is hydrogen peroxide bound to sodium carbonate, both of which I use in my pool. Does sodium carbonate break down Baquacil Sanitizer or does hydrogen peroxide?
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
14,500
Tucson, AZ
#4
How exactly does that work? Sodium percarbonate is hydrogen peroxide bound to sodium carbonate, both of which I use in my pool. Does sodium carbonate break down Baquacil Sanitizer or does hydrogen peroxide?
This thread is old by now but I'm happy to add to it for completeness sake.

First, yes, you could use sodium percarbonate to add oxidizer to the water but it would also add carbonate to the water which would drive the pH up very fast. So, unless you have a low TA water source where falling pH is a constant issue for you, I would not suggest using percarbonate. The main issue is that percarbonate would spike both your pH and alkalinity at the same time and could easily cause water cloudiness due to calcium scaling out of solution. In the extreme, you could get calcium scaling on your pool surface which would be difficult to remove.

Second, yes, sodium percarbonate can be used to destroy biguanide but the dosing rates are quite a bit higher that what is normally added by use of the standard baquacil oxidizer chemical. Both the baquacil oxidizer and sodium percarbonate add peroxide to the water and that peroxide does breakdown the biguanide sanitizer. However, the recommended levels of oxidizer called for in the baquacil system does not degrade the biguanide quickly. When one uses sodium percarbonate to convert a pool from baquacil to chlorine, the peroxide levels are a lot higher and the pH of the resulting pool water is also raised in tandem. The combination of high pH and presence of a strong oxidizer is what contributes most to the destruction of the biguanide. However, in practice, the percarbonate process is still a lot slower than using straight chlorine to convert a pool. The biggest benefit of using percarbonate is that there is less physical contamination to deal with when the reaction of chlorine and biguanide creates a sticky, gooey substance in the pool water.
 

del

Gold Supporter
Bronze Supporter
Apr 3, 2013
37
San Diego, Ca
#5
I can add a comment that may or may not be helpful. I use sodium percarbonate to kill algae in my Koi pond. It almost always leaves behind a lot of calcium carbonate precipitate at the bottom of the pond, which is sort of a problem, but managable. It does, of course, produce a lot of hydrogen peroxide at low cost. I am not recommending this, but it may, and I say may, be possible to put a little of the percarbonate into a plastic pail with water and then let it sit for a bit of time to let the calcium carbonate settle to the bottom of the pail. Maybe enough calcium carbonate will settle out that you can still use the hydrogen peroxide that is still in solution without disturbing the precipitated calcium carbonate. You will likely still get a big rise in pH and alkalinity, but likely not as much as would be the case of just putting the percarbonate directly into the pool. Again, this is just a thought, and I would encourge you to exercise caution in whatever you do. Getting rid of fine, precipitated calcium carbonate once in the pool it not an easy task. Good luck.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
14,500
Tucson, AZ
#6
I can add a comment that may or may not be helpful. I use sodium percarbonate to kill algae in my Koi pond. It almost always leaves behind a lot of calcium carbonate precipitate at the bottom of the pond, which is sort of a problem, but managable. It does, of course, produce a lot of hydrogen peroxide at low cost. I am not recommending this, but it may, and I say may, be possible to put a little of the percarbonate into a plastic pail with water and then let it sit for a bit of time to let the calcium carbonate settle to the bottom of the pail. Maybe enough calcium carbonate will settle out that you can still use the hydrogen peroxide that is still in solution without disturbing the precipitated calcium carbonate. You will likely still get a big rise in pH and alkalinity, but likely not as much as would be the case of just putting the percarbonate directly into the pool. Again, this is just a thought, and I would encourge you to exercise caution in whatever you do. Getting rid of fine, precipitated calcium carbonate once in the pool it not an easy task. Good luck.
Way back in the old days, when the rocks were still soft, old time pool pros would mix up calcium hypochlorite in a bucket of water to generate highly chlorinated water and let it sit so the calcium could precipitate out (if they were smart they added a little baking soda to make the precipitation happen faster). Then they would decant the liquid off which would be lower in calcium hardness. It's not a perfect method and there would still be added calcium to the water, but not as much if you just dumped in the cal-hypo all by itself.

Unfortunately this does not work well at all for percarbonates. The main problem is you will only generate a very weak solution of hydrogen peroxide. This happens because the percarbonate raises pH and peroxide is less stable as you increase pH and so it degrades rather rapidly into oxygen and water. Peroxide is only stabilized in acidic solutions and liquid peroxide bleaching agents typically have citric acid in them to lower pH. It would just be simpler and cheaper to go out and buy pool grade peroxide which is usually about 27% or 9X more concentrated than the little brown bottles of peroxide you get in the drug store. Pool grade peroxide can be found in any pool store that sells Baquacil chemicals because that is the "oxidizer" in the Baquacil process.