Just ordered tf100 XL and spinstir. Where do I begin?

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I have included yesterday and today's test. I did the CYA several times and I really did not see a difference even when I diluted the pool water per the CYA instructions

8/24
FC 16.5-18.5
pH 8.2
TA not tested
CH* not tested
CYA 90-100

8/25
FC 13 -14.5
pH 7.8
TA 140
CH* 225
CYA 100
 
Well, it looks like the only thing that's way out of whack is the CYA. 100 is too high.

If you have some algae, which is likely from the description as "cloudy" despite those FC numbers, then shock level would be 40ish. That's not really practical.

Step one is to replace some water with fresh tap water. Roughly half of it. But if groundwater is close to the surface where you live, it might be prudent to do it in two stages. It wastes some water, but that's small potatoes compared to a pool floating up and shearing off underground pipes.

Then you let the water mix well and retest and proceed from there. I suspect a SLAM is in your future. But if you follow our techniques, this could be the last time you ever have algae.
 
We are in the middle of the rainy season and it has been raining very hard the past few days so Im sure the ground is saturated. I have no problem draining some of the pool as long it doesn't turn into an above ground pool. Any other options other than draining 1/2 the pool?
 
rp7777 said:
I have included yesterday and today's test. I did the CYA several times and I really did not see a difference even when I diluted the pool water per the CYA instructions

8/24
FC 16.5-18.5
pH 8.2
TA not tested
CH* not tested
CYA 90-100

8/25
FC 13 -14.5
pH 7.8
TA 140
CH* 225
CYA 100
Click to expand...

If the dilution test looks the same as the normal test, your CYA is above 200 then, which is really high. You definitely need to do a series of partial drains and refills, just make sure your plaster doesn't start to dry out and crack. You can use a hose to spray down the sides while the water level is low. You'll likely drain maybe 1/3 of the water 3 or 4 times to get your CYA low enough. Perform a couple partial drains and refills, then test a day after you finish the last one to see where your CYA is at.

- - - Updated - - -

Actually, now that I reread your post, when you say you didn't see a difference between the normal CYA test and dilution test, do you mean that both times the dot disappeared around 100 on the vial, which means for the dilution test you'd multiply that by 2 to get 200 CYA? Or do you mean that in the dilution test you lost sight of the dot around 50, so you multiplied by 2 to get 100 CYA again? Either way its high, but higher means more to drain and refill.
 
...And this is why I bought the kit and reached out to you pool gurus. I was at the 100 line and I failed to multiply it by 2...So yes, my # is really 200. Thank you for pointing out my error. How low can you drain a pool during rainy season without it popping out of the ground?At this point I have no choice but to go that draining route.
 
Really, your CYA is above 200, and you could do the dilution test again to make it even more diluted and multiply by 4 I think, but its really not necessary unless you're curious. Just drain and refill several time and then test a day or so later (to let new and old water mix, turn pump on the whole time after you've refilled to ensure a complete mix). If its still reads 90-100 on the normal test, drain and refill some more. If you happen to drop below the 30-50 range, then its easy to bump your CYA back up.

Not sure how low you have to get to risk popping it out, but the rule of thumb for in ground vinyl pools is don't go below 1 food left in shallow end, so that should be safe for you too.
 
lightmaster said:
Really, your CYA is above 200, and you could do the dilution test again to make it even more diluted and multiply by 4 I think, but its really not necessary unless you're curious. Just drain and refill several time and then test a day or so later (to let new and old water mix, turn pump on the whole time after you've refilled to ensure a complete mix). If its still reads 90-100 on the normal test, drain and refill some more. If you happen to drop below the 30-50 range, then its easy to bump your CYA back up.

Not sure how low you have to get to risk popping it out, but the rule of thumb for in ground vinyl pools is don't go below 1 food left in shallow end, so that should be safe for you too.
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Draining is already underway. No point in testing again since I know draining is the only way at this point. You mentioned 1ft from the bottom for vinyl pools but a plaster pool. Just curious if there is a rule of thumb for that
 
I'm not sure, but I've heard that if you drain too much you risk floating the plaster up, especially if it's rained a lot lately. Until someone with more experience tells you otherwise, I wouldn't go below 1 ft in the shallow end.
 
lightmaster said:
I'm not sure, but I've heard that if you drain too much you risk floating the plaster up, especially if it's rained a lot lately. Until someone with more experience tells you otherwise, I wouldn't go below 1 ft in the shallow end.
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I drained the pool about 50% and stopped. All is well so far and I decided to do this because the back of my property which is about 10ft behind my pool slopes down about 2-3ft in that 10ft distance so if so if my water table were within 2-3ft I would assume there would be water at the bottom of the slope. Also I have a pond across the front of my house which is easily 6ft below grade from my property. I'm the end it was a scrap shoot.
 
rp7777 said:
I drained the pool about 50% and stopped. All is well so far and I decided to do this because the back of my property which is about 10ft behind my pool slopes down about 2-3ft in that 10ft distance so if so if my water table were within 2-3ft I would assume there would be water at the bottom of the slope. Also I have a pond across the front of my house which is easily 6ft below grade from my property. I'm the end it was a scrap shoot.
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Each time you drain half your water, you'll drop your CYA by half, since you're filling up with water that has 0 CYA. So if you started with 200, you'll have 100 this first drain, then 50 the second drain, and then 30 if you drain half again. Now your CYA could have been 250 or higher to start, so you could have more than 30 in the end, which is why I suggest the 3rd drain. Do your retest a day after the 3rd drain is finished filling back up.
 

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lightmaster said:
Each time you drain half your water, you'll drop your CYA by half, since you're filling up with water that has 0 CYA. So if you started with 200, you'll have 100 this first drain, then 50 the second drain, and then 30 if you drain half again. Now your CYA could have been 250 or higher to start, so you could have more than 30 in the end, which is why I suggest the 3rd drain. Do your retest a day after the 3rd drain is finished filling back up.
Click to expand...

The water remixes - the fresh doesn't stay perfect while you only drain the remaining CYA infused water, so you don't get a perfect half each drain unfortunately.

That said, OP, you're on the right track. Keep it up!
 
triptyx said:
The water remixes - the fresh doesn't stay perfect while you only drain the remaining CYA infused water, so you don't get a perfect half each drain unfortunately.

That said, OP, you're on the right track. Keep it up!
Click to expand...

Nothing about testing CYA is perfect, lol. Pretty subjective test that at best is accurate to within 10.
 
rp7777 said:
I tested my CYA today after filling up the pool again and letting it mix well.
CYA 100 without dilution
CYA after dilution method is 60. Times that by 2 and my real CYA # is 120.

Already draining the pool again
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That's a great improvement already, from 200+ down to 120! Just keep on with it an you'll have it down to a manageable level soon.
 
With all this focus on lowering your CYA, don't forget to keep an eye on your CH too. If it drops too low, causing your CSI to fall below -0.6, you risk the water pulling calcium out of your plaster, which can cause damage to it. Depending on your fill water, you might need to raise your CH back up.

Also, I don't recall you posting test results of your fill water. It would be useful to know what it's at so we can get an idea of how draining and refilling will effect everything else. For instance, my well water has a CH of 30, so I know that if I had a plaster pool, I'd have to be watching CH closely during a drain and refill cuz my CH would plummet.
 
8/24
FC 16.5-18.5
pH 8.2
TA not tested
CH not tested
CYA 90-100

8/25
FC 13 -14.5
pH 7.8
TA 140
CH 225
CYA 100
drained 1/2 pool

8/29/17 Filled pooled while running pump
FC 3
pH 7.5
TA 80
CH 150
CYA 120
Drained 1/2 pool 2nd time. Will fill tonight and tomorrow for another chemistry test.

I didn't know I had to test my tap water directly. Am I only checking for CH? Sorry I have no idea what one would find in tap water.
 
Fill water can be hard or soft, depending on how much calcium (and other minerals) one has in the water. I live in an area that has soft water, but folks out west often have hard, HARD water and deal with a lot of scale on the pools at times. Another thing is pH varies. You can test for everything *except* CYA- that's never in water naturally so no reason to test for it.

Maddie :flower:
 
If you check your tap water, whether from a well or city water, you can get an idea of how refilling will effect your pool. Your water is probably pretty soft since your CH is declining as you refill. Think of this, if you know your fill water has say CH 50, then you know that if you completely drain and refill your pool, that's what your new CH will be. Doing partial drains and refills means that while you'll never ends up with completely new water, so you'll never hit your fill waters CH, you will trend towards it. Having low CH fill water means your CH will decline as you refill and you'll need to raise it back up. I'm just using CH as an example, but same applies for pH, TA, and CH. Chlorine will degrade in the sunlight, so it doesn't matter what your fill waters chlorine is. If you're curious tho, well water had 0 FC, and city water typically has .5FC, sometimes up to 1 FC. Your fill water will never have CYA in it, so don't worry about testing that, just CH, TA, and pH.
 
Thank you. This is great to know and my 8 year old is having fun with it too. I will be ready to perform another test when I get home. Pool has already been refilled. I'm very interested in seeing my long term water quality by performing my own tests.
 
rp7777 said:
Thank you. This is great to know and my 8 year old is having fun with it too. I will be ready to perform another test when I get home. Pool has already been refilled. I'm very interested in seeing my long term water quality by performing my own tests.
Click to expand...

Keep records of your test results and you can see how your pool looks long term.


Note that I recently changed increased my CYA, so the time where FC was red at the left was in the green at the time.
 

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