A very interesting article in Aqua Magazine scale in a sWCG

[PoolGuyNJ]

There are a couple of minor nits but overall, I think it's pretty good reading.

http://aquamagazine.com/articles/article.aspx?articleid=2021&zoneid=60


Scott

 

[chem geek]

Re: A very interesting article in Aqua Magazine scale in a s

In that article it states:

It should be mentioned, he adds, that due to that steady production of NaOH, the pool in general is always drifting upward in pH. Over time, if the overall pool pH is not maintained within limits, there will be issues — among them scaling in the entire pool, not just the ECG.

This is not the whole truth. Yes, there are hydroxyl ions produced (actually, hydrogen ions removed to produce hydrogen gas and then water fills in with more hydroxyl ions), but the chlorine gas that dissolves produces hydrogen ions so the net result is essentially the same as using a hypochlorite source of chlorine (see this post for more technical details).

The pH does not have to keep drifting upward and can be managed through techniques well-known on this forum including having a lower TA level, a higher pH target, a higher level of CYA, and use of 50 ppm Borates. Though there may potentially be some leftover pH rise from undissolved chlorine gas outgassing, it is wrong for the article to imply that the SWG is putting out the equivalent of lye on a continual basis. The article completely ignores the fact that chlorine usage/consumption is acidic so compensates for the initial pH rise from chlorine production.