Chemistry addition vs water level


Active member
Jul 9, 2016
Valparaiso, IN
The sun is shining and my pool is open in northwest Indiana!
We closed late and have opened early. Water looks pretty much perfect.

My sweet spot for the water level is the second screw head up from the bottom on the skimmer mouth. The skimmer will take in water 2" below and almost 2" above that point but that's the magic spot I settled on.
My question is this..... Since I set my "gallons" to be 17,100 (27' X 46") in pool math, what affect does less or more water make to the health of the water? Those 2 inches amount to several hundred gallons. When it comes to gallons in Pool Math, I usually set it and forget it.
(I do manage the water in the pool, but not usually until it gets to either extreme).

Edit......For whatever reason I had been using 17,100. But 27'x46" is actually 16,500.


Mod Squad
TFP Expert
LifeTime Supporter
Apr 17, 2010
East Texas
Just calculate your gallons to the height you keep your water level at. Only one that matters! Either add or subtract those several hundred gallons when you calculate additives.


Active member
Jul 9, 2016
Valparaiso, IN
Ok, maybe a better often do you add water to your pool, even if the water level is appropriate for the skimmer level, but NOT the calculation you entered into pool math?


Bronze Supporter
TFP Guide
Jul 24, 2015
Central Valley CA
Even a 1000 gallon swing should only change your bleach additions by an ounce or so, when I was manually adding I am sure I was +/- a couple of ounces each time as I was not using a measuring cup just graduated approximations on my bleach bottle. I don't think you will have a problem, I should however admit I have an auto fill.


Well-known member
Aug 30, 2016
Riverside, CA
We're talking parts per MILLION in 10's of thousands of gallons. A couple hundred gallons isn't going ti make a difference at all.

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