Rust Spots

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J

johnboy85

0
Aug 17, 2015
27
Hernando/Florida
I just purchased a new home that has an in-ground pool. I noticed that there are a bunch of what looks to be rust spots. There seems to be more and more as time goes on. I was told that the pool has a diamond bright finish. I was under the impression that diamond bright finishes do not rust. I am not sure what the problem is. Any suggestions would be great.
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How about getting a water sample and running down to the pool store and asking them to run a test for metals?

Do you know if any copper algaecide has been used in the pool??

Get some Vit C tablets and hold it against the stain and see if it disappears. If it does, you have metal staining.
 
I ordered the TF-100 test kit and here are the results I came up with:

Cl/BR seems to be off the charts and the PH is at 7.2
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Chlorine test FC 21.5ppm
Total Chlorine - No CC

Calcium hardness 525ppm

TA- 90
CYA- 90

- - - Updated - - -

Thanks Yippe, I have a pinch a penny about a mile from here. I am assuming they could probably test for metal.
 
Wowsa! I don't think I've ever seen the OTO block with red on the chlorine side??

As to the scary looking low pH-->with that high of FC, your pH is NOT accurate. <whew!>

Have you been using CalHypo to chlorinate??
 
I also have a questions about checking the calcium hardness. The index card that comes with the kit has a different test than that of the youtube video here:
Calcium Hardness with the TF-100 - YouTube

If I use the test method that comes with the kit I get 525ppm, with the test method in the video I get 450ppm. I can see the color change a lot easier with the video method but it does use more reagent. Which test method do you guys think is more accurate?
 
Wow- it was almost painful to watch all that manual swirling. Get that man a magnetic stirrer!

I'm not sure what your index card instructions say because mine call for it to be performed exactly like the video.
 
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Here is what my index card says for the calcium hardness test:
fill cylinder with pool water to the 10ml mark,
Add 10 drops of R-0010 and mix,
3 drops of R-0011L
Add R-0012 one drop at a time until the color changes blue
Multiple the number of drops x 25

Here is what the Youtube video says for the calcium hardness test:
fill cylinder with pool water to the 25ml mark,
Add 20 drops of R-0010 and mix,
5 drops of R-0011L
Add R-0012 one drop at a time until the color changes blue
Multiple the number of drops x 10
 
There is no need to be that accurate with the CH test. The TF-100 instructions recently were changed to the 10ml water sample add that is good enough and gives you more tests.

The OTO tests turns orange like that at higher chlorine levels. Like you found your FC is over 20ppm.

With high FC over 10ppm, the pH test reads higher than reality. That worries me that your pH might be really really low.
 

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See this old thread that talks about off the scale reading on the OTO Chlorine test Extended OTO color comparator?


As to the spots they may very well be rust spots precipitating out of the water due to the VERY high Chlorine level, there are any number of possible sources for the metals including fertilizer for the grass getting blown into the pool.
 
What should be the next step that I focus on? It has been raining here like crazy, should I just leave the pool alone and see if the chlorine drops and then address the PH if it's low? I see that my CYA is high, should I address that first? Not really sure where to go from here.
 
Stop adding Chlorine until it gets down to sane levels, if it were mine I would start with water replacement to bring the CYA down to something reasonable right away, given you are in FL I would aim for 50 ppm CYA, this will require replacing about 1/3 of your water. This assumes you are going to continue to manually add chlorine, if you plan to switch to a SWG for chlorination your CYA target should be around 70. Once the water is back up to its normal level adjust pH as needed.

Ike

p.s. to be safe if you have a high water table, you might want to do 2 smaller drains and refills to lower the chance of your pool floating out of the ground
 
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