Pool calculator Q

MIDSOUTH

Member
Jun 29, 2010
14
League City, Texas
After getting 2 different test results from 2 different pool stores; found this site and ordered the TF-100--should be here pretty quick! Anyway, really appreciate all the advice in this forum-especially the BBB! But I have a question about the pool calculator. My levels (according to the pool store) were right on target..finally after having to drain approx. 29in of water to reduce the salt level and adding acid and CY Test results as of 6/27/10:
FC: 5
Salt: 3500
CH: 280
CA: 30
TA: 80
PH: 7.2

When I input these numbers into the pool calculator, it shows a CSI as -.55????? Does the calculator automatically take the above numbers and calculate-or do i need to calculate my own CSI?
 

svenpup

LifeTime Supporter
Nov 18, 2009
835
Sacramento, CA
If I assume your temp is around 86 I get the same CSI as you.

Knowing this, you will want to keep your pH higher (7.5-7.8) and your CSI will be fine (0.26 - 0.03).

This will be no problem, as pH will tend to drift up with an SWCG.
 

svenpup

LifeTime Supporter
Nov 18, 2009
835
Sacramento, CA
What was your pH before the muriatic acid and what was your target pH?

In the future, when you get to pH=7.8 add only enough muriatic acid to get down to 7.5
 

Melt In The Sun

TFP Expert
LifeTime Supporter
Oct 29, 2009
3,899
Tucson, AZ
No real worries; just keep an eye on it. You can get pitting of your plaster if CSI is very low for a looong time, but you're not in danger at -0.55 for a little while.
 

MIDSOUTH

Member
Jun 29, 2010
14
League City, Texas
svenpup said:
What was your pH before the muriatic acid and what was your target pH?

In the future, when you get to pH=7.8 add only enough muriatic acid to get down to 7.5

The PH was 8.0 and target was ???? (I guess anything between 7.2-7.6). I have scaling--calcium I think and thought that the lower PH would help to get rid of it? Can't wait to get the TF-100 and start testing myself. One pool store said that CH was low and on the same day, the other pool store said it was fine.
 

svenpup

LifeTime Supporter
Nov 18, 2009
835
Sacramento, CA
Quoting from the pool school article on scaling:
Pool School said:
Calcium scale can be very difficult to remove. Small patches of scale can be removed with a pumice stone. In mild cases, lowering your CSI to about -0.8 and brushing aggressively can sometimes remove scale, particularly when a sequestrant designed for calcium is also used, but this can take weeks and you need to be careful not to lower your PH too far of you can damage copper heat exchange coils. There are no drain acid wash systems, such as Jack's Magic The Copper & Scale Stuff, but the heater (if any) must be bypassed and the process can take weeks. The only reliable solution for removing calcium scaling is a full drain and acid wash.
I'm not sure if this is what you are trying to do. If not, try to keep your CSI slightly negative (-0.3 to 0).
 

MIDSOUTH

Member
Jun 29, 2010
14
League City, Texas
I have stains and scaling. The stains came from the lid of a candle that fell in the pool last winter and stayed for a while without me noticing-it was a white metal lid. We have a tanning ledge which our dd put a chair on and that caused some rust stains. Sooo, I tried the vitamin C tab to make sure that it was a metal and it did not dissolve the stain on the tanning ledge. I had put a trichlor tab in a sock and put it on (what I think) is calcium scaling and thought I saw a difference so, having nothing to do this evening, took the sock with the tab in it and started scrubbing the tanning ledge. Much to my surprise and delight the scaling started coming off. So, I took 2 tube socks and layed 5 tri-chlor tabs in each and layed them on the "calcium stains" on the surface of the shallow end of the pool. I'll leave them there until much later this evening and see if it makes a difference :). I also changed my timer for the pump to start at 3am (to get the most out of the SWG in the dark) and leave it on until 1pm. See if these ideas will make a difference!
 

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