Tested My Tap Water

[Lord Bodak]

I took my new Taylor 2006 for a spin with the water from the hose we'll be filling the tub with, and here's what I got...

pH - 8.0

Acid Demand - 1 drop lowered pH to 7.4

TA - 70

CH - 20

And just out of curiosity... FC of 0.6 and CC of 2.0

So it looks like I need to bring the calcium up a bit and the pH down a bit. Anything else that I'm missing?

I'm thinking 120 for CH and 7.6 for pH, which with my other readings, plus a goal of 30 CYA and 50 Borates, gives me a CSI of -0.24 at 100 degrees. How does that look?

Edited July 26, 2010 by Lord Bodak

[waterbear]

I took my new Taylor 2006 for a spin with the water from the hose we'll be filling the tub with, and here's what I got...

pH - 8.0

Acid Demand - 1 drop lowered pH to 7.4

TA - 70

CH - 20

And just out of curiosity... FC of 0.6 and CC of 2.0

So it looks like I need to bring the calcium up a bit and the pH down a bit. Anything else that I'm missing?

I'm thinking 120 for CH and 7.6 for pH, which with my other readings, plus a goal of 30 CYA and 50 Borates, gives me a CSI of -0.24 at 100 degrees. How does that look?

Sounds like you got a handle on it. BTW, when you fill the spa shock it to 10 ppm and keep the cover off and jets running to get rid of the choramines in your tap water. Do this in daytime since sunlight is part of the equation to get rid of chloramines.

Don't get so hung up on the CSI. Unless your tub is made of plaster it's not that important. Just enjoy the tub one you get the water balanced to where you said you were going with it and keep it there.

[quantumchromodynamics]

Don't get so hung up on the CSI. Unless your tub is made of plaster it's not that important.

A high CSI can cause scaling as shown in this post.

[waterbear]

Don't get so hung up on the CSI. Unless your tub is made of plaster it's not that important.

A high CSI can cause scaling as shown in this post.

As I stated in the thread you referenced above:

"Scale forms when calcium hardness, pH and TA are high. Please post a full set of test results (NOT from strips) and we can take it from there. The only thing that removes scale is muriatic acid. It is better to prevent it by paying attention to your water balance."

That is not the case here.

As the OP stated, along with his TA of 70 ppm:

TA - 70

CH - 20

I'm thinking 120 for CH and 7.6 for pH, which with my other readings, plus a goal of 30 CYA and 50 Borates, gives me a CSI of -0.24 at 100 degrees. How does that look?

If his fill water had a very high CH then I would have said other wise but he is filling with soft water so KISS!

IF there was high TA and CH in the fill water then I would have suggested to keep close tabs on pH since that is the main controllable factor in determining conditions likely to form scale. (And the one with the biggest effect in the SI equation with Temperature having the next biggest effect. However, temperature is not one that we can really adjust to prevent scaling and still have a 'HOT" tub.) It takes very small changes in pH and temp to make big changes in the SI while it takes much larger changes in CH and TA to move the SI.

I stand by what I said. In the OP's case SI is not something he really has to worry about if he keeps his water in the ballpark of what he is proposing and even if his pH spikes there will be very little chance of scaling, given the low TA and CH. I calculate the SI with these parameters and a pH of 8.0 at only +.06 which is NOT a scaling risk at all. Even if he rasied the temperature to 104 degrees the SI would only rise to +.09.

KISS

[quantumchromodynamics]

OK, my primary concern was that the poster was going to be adding calcium and I wanted to be sure that they didn't overshoot the mark and end up with a high CSI. I should have written my post more clearly.

[waterbear]

IMHO, people get too hung up in SI. In reality pH is often the only factor that can readily be conrolled to it is more practical to keep close watch on pH when there is the possibility of scaling conditions.

If the surface is plaster then we do need to look at aggressive water conditions (low SI) but once again, pH is usually the main factor to watch here ifr CH is not allowed to drop way low.

I have found that pool owners are more likely to comply if you tell them to keep their CH in a certain range and TA in a certain range (and in many cases these are not going to be ideal because of regional fill water variations) and have them keep a close monitor on pH and keep it in a more narrow range instead of fluctuating all over the place. It give them really only one thing to worry about besides sanitizer levels and they are more likely to do it (and have far fewer problems with scale or plaster degradation as a result). TA and CH tend to stay pretty stable. pH and Temperature tend to fluctuate and have more impact than either TA or CH so grant me the serenity to accept the things I cannot change, usually temperature, CH and TA;

courage to change the things I can, usually pH;

and wisdom to know the difference... KISS

With apologies to the Serenity Prayer