Is our SWG too powerful for our small pool?

setsailsoon

LifeTime Supporter
Oct 25, 2015
599
Stuart/FL
#42
Pool owners experience pH rise when the switch to SWG's NOT because of the SWG but mainly because they were previously using an acidic form of chlorine (dichlor powder and/or trichlor pucks). The acid released from those chlorine sources would slowly reduce TA over time and help suppress the natural pH rise of the water. Then, when the switch is made to net-neutral pH sources of chlorine (SWG's or liquid chlorine), there's a sudden rise in pH because there is no longer anything acidic being added to the pool. As the old adage goes, correlation does not equal causation!
Now that makes a lot of sense Matt! I see the opposite affect when switching to tablets for a week or so when I'm out of town. Never have to add acid and pH is lower than normal when I get back. As I transition back to liquid chlorine I have. to start adding acid but not huge amounts. Usually around 10 oz per week or so. We do also run the spillover all the time for the aesthetics.
 

Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2009
22,894
SouthWest Alabama
#44
Keep in mind that in use liquid has a net neutral pH. The liquid has a high pH but the process of sanitation has an acidic pH, so the net pH of using liquid is neutral.
 

PoolGate

Gold Supporter
TFP Guide
Jun 7, 2017
2,482
Damascus, MD
#45
No one that has followed the advice of this forum has ever had a problem with pool water chemistry. You can choose to follow your friend's, or the pool store, or someone else' advice, but once you take this forum's advice you will start to enjoy your pool more. First step is to get a proper test kit, the TF-100. Until you can do your own testing, your pool water chemistry will be a mystery.
 
Likes: Jimrahbe

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
14,492
Tucson, AZ
#46
Now that makes a lot of sense Matt! I see the opposite affect when switching to tablets for a week or so when I'm out of town. Never have to add acid and pH is lower than normal when I get back. As I transition back to liquid chlorine I have. to start adding acid but not huge amounts. Usually around 10 oz per week or so. We do also run the spillover all the time for the aesthetics.
Thanks, Chris.

It's important to keep a proper perspective on these issues because one of the biggest fallacies that is thrown around is how a chemical is going to cause some drastic change in pH and wreck the pool. Too often the industry spoke against using liquid chlorine because "it raises pH" and "high pH means less effective chlorine" with both statements having a kernel of truth in them but are demonstrably false for other reasons.

Take the "high pH of bleach" claim - while it is true that bleach, as part of it's manufacturing process, contains caustic soda (sodium hydroxide) in order to stabilize the hypochlorite from degradation, the amounts we are talking about are minuscule. Yes, liquid chlorine drawn from a bottle of bleach has a pH of 12.5, that does not mean when added to a pool one will suddenly get high pH. Adding a gallon of bleach to 10,000 gallons of pool water will have an almost immeasurable effect. For example, adding 128 fl oz of 8.25% Clorox bleach to 10,000 gallons of pool water will increase the FC by 8.6ppm but have almost no effect on pH. If you look at the detailed chemistry, it raises the TA by 1.1ppm and that would require about 1.6 cups of muriatic acid to neutralize. The pH change would be immeasurable with most standard test kits. Over time, a pool owner is going to add more TA from fill water then they will ever add from using liquid chlorine.

Trichlor is a bit different as it is definitely very acidic which is well know as inline puck chlorinators need check valves installed in order to keep the acidified water inside them from back flowing into delicate equipment, like a pool heater. 16 oz of trichlor (about two standard 3" pucks) adds as much "acid" as 9.3 fl oz of MA and will reduce the TA by 3.6ppm. It will also lower the pH by about 0.2 units. However, one has to realize that the dissolution of trichlor pucks inside a standard pool float is fairly slow and so there's no reason to worry too greatly about a sudden pH drop. Again, the presence of high TA fill water will more than likely help offset some of the TA loss caused by trichlor.

Every chemical has it's appropriate use and, as long as pool owners understand what they are adding to their water and do so in a safe and efficient manner, there's not a lot that can go wrong. Bad advice and inconsistent pool care do far more damage than any one chemical...
 

Sharkygirl

Well-known member
Oct 26, 2014
62
Key West, FL
#47
Hi Rachelmarie, you will get the hang of it. Once you get your test kit, go ahead and test your water several times. At first it seems it is so foreign and everything goes so slow. But when you do it several times in a row, you will get the hang of it. I wouldn't turn off your SWG just because you creeped up a little on your chlorine. Do you get any direct sunlight in your pool? You can go up or down in 5% increments. You can also lower the amount of run time on your pumps. So instead of 8 hours, you could back it down to 6. Just a thought. Oh, and since your pool is so new, don't forget to brush it every day. You can never brush enough!