1. ## Pool calculator discussion

Why use poolcalculator dotcom when there's a link to Pool Math at the top of this page?

moderator Note - this side discussion was moved out of this thread Straddling the BBB conversion...

2. ## Re: Straddling the BBB conversion...

Originally Posted by Skitch
Why use poolcalculator dotcom when there's a link to Pool Math at the top of this page?
The poolcaculator correctly reports the required mustard algae shock level for high CA levels. When I first arrived at TFP with CYA 300 and mustard algae, I was confused by Pool Math's error.

3. ## Re: Straddling the BBB conversion...

Originally Posted by CA92807
The poolcaculator correctly reports the required mustard algae shock level for high CA levels. When I first arrived at TFP with CYA 300 and mustard algae, I was confused by Pool Math's error.
I'm confused by that statement. Could you explain? Maybe with example?

4. ## Re: Straddling the BBB conversion...

I'm confused by that statement. Could you explain? Maybe with example?
Open PoolMath with normal values and set CYA to 300. Look at Mustard Shock Level and you will see 15. If you mouse over this field, the value helper correctly shows 154, but my first visits to Pool Math really confused me. I had CYA 300, was using pucks, test strips and looking for help. Eventually I struggled through, took some Pool School lessons and now my pool is trouble free. I reported the PoolMath bug a few months ago but was told bogus results weren't worth discussing.

5. ## Re: Pool calculator discussion

I believe the pool calculator website is out of date and no longer being actively maintained. So there are errors in using that.

As for PoolMath, I think what you have to understand is that PoolMath does the ACTUAL mathematical calculations based on a lot of the equations that were developed by chemgeek and JasonLion as opposed to the pool calculator website which uses look up tables. PoolMath's results are accurate within reasonable limits. A CYA of 300ppm is not reasonable and is something that has to be addressed by drain and refill regardless of the presence of algae. The reason being is that the FC levels needed for a CYA of 300ppm are astronomical and would require a person to add many, many gallons of bleach into the water and maintaining that level would be difficult. Not only would that be difficult from a logistical perspective, but there would be no accurate way to test FC levels that high and the excess lye and salt added by using that much bleach would seriously impact other water values like pH.

So asking PoolMath to calculate a shock level FC for a 300ppm CYA is just not reasonable. Perhaps the solution is to change PoolMath so that values of CYA above 150ppm just instruct the user to drain and refill.

6. ## Re: Pool calculator discussion

Joyful - I second that idea!

7. ## Re: Pool calculator discussion

Ive been using pool calculator. I thought they were the same.

8. ## Re: Pool calculator discussion

When I first arrived at TFP (via an outside link to PoolMath) a year ago having a weekly pool service, advice from a pool store, CYA 300 and ongoing problems with mustard algae I was looking for a solution. I had no idea what was wrong. When I plugged my pool's numbers in, I got a shock value of FC 15 that seemed reasonable to me. Shock is what you do when you have a problem. If it had displayed the correct value I wouldn't have even considered it. Ultimatly I was able to control but not eliminate my Mustard Algae using alternative solutions. Fortunately I discovered the main TFP site while researching VS pumps. A year later I know a lot more about running my pool and with new water and a Stenner CL pump, it's really trouble free. The TFP site has been invaluable. I don't understand the reasoning that says it's OK for PoolMath to give bad answers because the user should know better. I didn't when I first arrived.

9. ## Re: Pool calculator discussion

Hench the reason for the forum. For things that don't make sense, you ask.

10. ## Re: Pool calculator discussion

I don't disagree that PoolMath should give self-consistent results - if PoolMath calculates a number in one field but then displays the wrong value in another field, then that is a bug that ought to be investigated and fixed.

But PoolMath and the pool calculator website are different things now. TFPers should be using PoolMath as it is the most up to date in terms of calculations and available chemicals. Using the pool calculator means you are using outdated and unsupported information.

I'm glad you eventually found TFP. Most people land at the TFP Home page not straight away at PoolMath. So if someone lands at PoolMath and starts using it without understanding where it came from, well that's a lot like a person using a table-top radial saw without knowing the first thing about woodworking - not a good idea and you're liable to lose a finger

Perhaps this discussion will get mentioned on the moderator/admin forum so they can look into what's going on with PoolMath.

11. ## Re: Pool calculator discussion

Originally Posted by JoyfulNoise
that's a lot like a person using a table-top radial saw without knowing the first thing about woodworking - not a good idea and you're liable to lose a finger
That is usually referred to as a RAS: radial arm saw. You'll want to use a negative hook blade on it. LOL...yes, woodworker here when I'm not in my pool!

12. ## Re: Pool calculator discussion

Unless you're face cutting a laminate.

13. ## Re: Pool calculator discussion

I assume it's the way the field length for the box is set in PoolMath - probably truncates after two characters.

It's a typical programming bug (breakdown at unanticipated boundary conditions). Such bugs, hopefully, should be fixed when noticed, although that would depend on when the person/people maintaining the program have time to fiddle with it. I sure hope no one is defending this quirk as a feature, or saying it's just fine as is. JoyfulNoise's suggestion (end of post #5) seems like a good one.

14. ## Re: Pool calculator discussion

So we have a third!! The motion carries...

15. ## Re: Pool calculator discussion

Originally Posted by JoyfulNoise
Perhaps this discussion will get mentioned on the moderator/admin forum so they can look into what's going on with PoolMath.

Sent from my iPhone using Tapatalk
This "issue" has been known for a few month's now. I'm hoping to be able to address this in the future next time we update PoolMath. When that will be, I'm not sure of, but it is on a "to-do" list.

16. ## Re: Pool calculator discussion

Originally Posted by JoyfulNoise
I believe the pool calculator website is out of date and no longer being actively maintained. So there are errors in using that.

As for PoolMath, I think what you have to understand is that PoolMath does the ACTUAL mathematical calculations based on a lot of the equations that were developed by chemgeek and JasonLion as opposed to the pool calculator website which uses look up tables. PoolMath's results are accurate within reasonable limits.
Actually, both calculators use a combination of techniques depending on the calculation. PoolMath did continue to get updated so has a few changes/improvements, but I don't think there is anything radical such as moving from lookups to exact calculations. Basically, exact calculations were always done where it was easy to do and lookups were done where such calculations were not easy, such as pH.

For me right now PoolMath doesn't truncate to "15" and is showing "154" (so maybe this is browser/OS specific) but the actual value for yellow/mustard algae shock level would be closer to 169, but the CYA level is so high that such FC levels aren't realistic. Also, at such high FC levels, the chlorine bound to CYA needs to be taken into account and we don't know enough about its weak ability to kill algae (if any). We know there is a low oxidizing capability less than 1/150th that of hypochlorous acid.

17. ## Re: Pool calculator discussion

It's not truncating the value, only its display. If you doubleclick the value, copy and then paste into a text editor you'll see the whole value. So it's simply the size of the text box that has been fixed at a too narrow width.

Adjusting the size of the text box should be an easy fix.

18. ## Re: Pool calculator discussion

The correct number is actually there, the cell it's in just isn't big enough to display the whole thing. You can see the number by hovering over and looking at the Detail box to the right of Temperature.

19. ## Re: Pool calculator discussion

Size parameters need increased, starting at line 1341. I recommend 3,3,3,5,5.

Code:
```<nobr>SWG:<INPUT type=text name="SUGFCswg" size=2 value="2" readonly class=ClassSUG onmouseover="StatusSUG('SWG',document.F.SUGFCswg.value);" onfocus="StatusSUG('SWG',document.F.SUGFCswg.value);"></nobr>
<nobr>Normal:<INPUT type=text name="SUGFCmin" size=2 value="3" readonly class=ClassSUG onmouseover="StatusSUG('Minimum',document.F.SUGFCmin.value);" onfocus="StatusSUG('Minimum',document.F.SUGFCmin.value);">
to <INPUT type=text name="SUGFCtarg" size=2 value="6" readonly class=ClassSUG onmouseover="StatusSUG('Maximum',document.F.SUGFCtarg.value);" onfocus="StatusSUG('Maximum',document.F.SUGFCtarg.value);"></nobr>
<nobr>Shock:<INPUT type=text name="SUGFCshock" size=2 value="15" readonly class=ClassSUG onmouseover="StatusSUG('Shock',document.F.SUGFCshock.value);" onfocus="StatusSUG('Shock',document.F.SUGFCshock.value);"></nobr>
<nobr>Mustard Algae Shock:<INPUT type=text name="SUGFCmust" size=2 value="24" readonly class=ClassSUG onmouseover="StatusSUG('Mustard Algae Shock',document.F.SUGFCmust.value);" onfocus="StatusSUG('Mustard Algae Shock',document.F.SUGFCmust.value);"></nobr><br>```

20. ## Re: Pool calculator discussion

This issue has been updated and fixed. Thanks Skitch for pointing this out to us.

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