Ch = 1400!!?? sanity check please.

[questhe]

It took 140 drops and constant swirling to turn the cylinder blue. This is my first test with the TF-100.
Readings:
PH 7.2
FC 5
CC 0
TA 60
CH 1400
CYA 45

I have a 25 year old plaster pool, 20,000 gallons, SWG and sand filter w 3/4 Jandy Stealth. I just re-started a negative edge waterfall feature that runs through a 700 gallon sump by replacing the pump with a 1 HP Northstar . The pool plaster is starting to crumble. I wonder if poor chemistry dissolved the plaster, or the plaster is just dissolving into the water?
I have been shocking with tri recently, and I add acid regularily.
I'll run the CH on the tap water and post that up, too.

 

[lightingguy]

I'm so relieved to find someone with higher CH than me (1100) It just killed me to use 1/2 bottle of reagent on my first CH test... sigh.

Our water clouds up when the PH and TA drift too high, but other than that it hasn't been too much of an issue.

Our plaster is similar age - around 30 years and crumbling.

Everything I've read about plaster and chemistry involves low CH levels and low PH leaching calcium from the plaster.

Anyone know of a high CH situation where the water chemistry can damage the plaster?

Your plaster is probably just at the end of it's serviceable life.

 

[JasonLion]

Welcome to TFP!

Where do you live? If your fill water CH level is also high and you live in an arid area, having a high CH level makes sense.

How old is the plaster? Plaster does fail and start to crumble when it gets old. If it is 25 years old, it lasted longer than plaster usually lasts. It can also do that when the PH has been much lower than it should be for a long time.

 

[svenpup]

...Anyone know of a high CH situation where the water chemistry can damage the plaster?...

It causes scaling if your Calcite Saturation Index (CSI) is too high. Check out this recent post which has pics of bad scaling.

 

[lightingguy]

I recognize that sandpaper look.... sigh.

But this doesn't really damage the plaster perse - doesn't cause it to fail and crumble - right?

 

[svenpup]

Just bad for aesthetics and skinned knees

 

[questhe]

OK, re-test pool using 10 ml water, required 62 drops = 1550 ppm CH.
Tap water was 22 drops = 550 ppm CH.
This is in Mesa, Az. My water softener is set to 18 grains hardness. Does that check out?
csi is -0.05 assuming 2000 ppm salt.

My guess is that evaporation has caused the CH to concentrate. Last water change was ~3 years ago.

 

[JasonLion]

Yes, evaporation plus topping off the pool will tend to raise the CH level over time.

With fill water that high in CH and not changing the water for three years, it makes a lot of sense that your CH level is that high.

I recommend getting a reverse osmosis treatment to bring the CH level down to something reasonable. There is at least one company in your area that does those treatments, Calsaway.

 

[questhe]

I just called, got an estimate of $500 for their treatment.
Not a bad price, but I am planning to re-finish the plaster, so I'll have to drain it then.
I can't drain it in the summer here, with daytime temps in the 100s, right?

So, when I drain it in Oct. for the refinish (thinking Epoxy paint), I can re-fill it.

Q: Should I re-fill it from my water softener? Should I buy my own R/O unit?

 

[Melt In The Sun]

questhe, I something seems odd here. Your softened water has a CH of 550?

 

[questhe]

No, that is a garage tap that is un-softened, same as the spigot that fills the pool.
Great catch! I'll have to check the kitchen sink water.
Then I can test the R/O tap and see what it contains. Probably all 0s. It can generate about a 1/2 gallon a minute. How long would it take to fill my pool?

 

[zea3]

No one has mentioned this yet but did you wipe the tip of the reagent bottle with a damp cloth between drops? The reagent tends to build a static charge on the tip that causes smaller drops, thus a higher drop count to get the required reaction.

 

[svenpup]

No one has mentioned this yet but did you wipe the tip of the reagent bottle with a damp cloth between drops? The reagent tends to build a static charge on the tip that causes smaller drops, thus a higher drop count to get the required reaction.

The static issue only affects the TA test.

 

[chem geek]

Static can affect any reagent -- it is only more common with TA, but I believe I saw a report on this forum somewhere about someone also having a problem with the CH test. So it's certainly something to double-check to make sure that the drops are well-formed "hanging" drops and not something that "squirts" out in small amounts.

 

[svenpup]

Good info Richard...I had only ever seen static referenced in association with the TA test.

 

[questhe]

Well, for my lazy ***, 140 drops was too many to wipe.

Edit: no, sir, I did not wipe. So, How much error might there be?

I guess this explains all the little white granules that are showing up in my strainer sox after I put in clarifier and algecide. good thing I held off on the phosphate treatment!

I am planning on adding Borax - comments?

 

[duraleigh]

questhe,

1. Next time you do the test, use a 10ml sample of pool water and perform the test as usual.....now each drop has a value of 25 instead of 10.....you should use about 50-60 drops if you really are at 1400.

2. I can't remember any instances of static electricity affecting the CH test. However, there may be something isolated that I have missed. From what I can remember, it seems to be exclusive to the R-0009 in the TA test.

3. I would suggest getting your pool in good balance before you attempt the borates.

 

[PaulR]

For the Calcium Hardness test you can use a 10 mL sample, 10 drops of R-0010, 3 drops of R-0011L, and each drop of R-0012 then counts as 25 ppm.

From alternate-test-procedures-for-the-tf-test-kit-t1723.html

 

[questhe]

Actually, that is how i did the retest in my post above:

OK, re-test pool using 10 ml water, required 62 drops = 1550 ppm CH.
Tap water was 22 drops = 550 ppm CH.

 

[Guest]

Do not drain your pool in your heat (or you will see more plaster "falling off"!). If you got 25 years out of the plaster, then you did well!

Save your money for a replaster. Paint is a short term fix, and a poor one at that. If your plaster is to the point of delamination now, then there is a good chance that there is more to come, and you will not be able to prep well enough for paint (and the paint will maybe give you 2-3 years anyway). Save the paint money and put it toward a replaster, It may take a while longer, but it will be well worth it.