My "Giant Pond" is Almost a Real Pool! And Some Questions...

[reebok]

I did the FC Loss Test last night. I had a drop of .2 between 8:30PM last night and 5:30AM this morning, so I assume that's good? It said 1.0 or less drop is OK, right?

I am still waiting for the CYA in the sock to dissolve (which is hanging near a return), but I am getting FC readings of 0 at the end of each day. I'm not sure I am adding enough bleach, but am doing what the pool calculator is telling me, provided I am using it right. It says my FC goal should be "2 to 6," and with the target set at 3 (which is where it was when I first opened it--I didn't change it) the amount of bleach it recommends I add is bringing me to the 3.4-3.6 range (it was 3.4 just now after being 3.6 last night). I assume it is all being eaten up by the sunlight since the FC Loss Test seemed OK, and the stabilizer hasn't dissolved enough to have any effect yet. Is this normal for a newly filled pool? Am I adding enough bleach? Should I raise the target on the pool calculator or is this sufficient?

The pH is holding steady at 7.4, and the TA at 70. I haven't tried retesting for CH yet, and testing for CYA seems useless until the stuff in the sock dissolves (right?). So, is there anything else I should be doing right now?

ETA: I should probably add that it's pretty hot here right now. Today's temp is predicted to be 97, and it's forecast to range anywhere from 94 to 101 over the next 10 days. The pool gets a full day of sun. The shallow end is shaded after about 3-4PM, but the deep end is in sun all day from about 7-8AM until about 6-7PM. Don't know if that makes any difference, but thought I should note it.

ETA again: One more question about the pool calculator... When I first open it, it says my FC Goal is "2 to 6" like I said above, but once I fill in my "Now" values and click "Calculate," the FC Goal changes to "1 to 3." Why is that? Is it because of the 0 CYA value? Or something else? Just want to be sure I'm getting the correct results.

your overnight fc loss is fine. your huge problem is you're letting the fc get to 0. you're supposed to shock if you let that happen. yes you're losing it to sunlight. wait a week after the cya dissolves to test. different things affect the recommended ranges for the calculator. if you change your cya level it will change the recommended fc level. I highly recommend you read pool-school/ pool chemistry section because it will answer these questions you have and will give you a much better understanding of pool chemistry which will make the calculator make more sense.

 

[WaterWoman]

I did the FC Loss Test last night. I had a drop of .2 between 8:30PM last night and 5:30AM this morning, so I assume that's good? It said 1.0 or less drop is OK, right?

I am still waiting for the CYA in the sock to dissolve (which is hanging near a return), but I am getting FC readings of 0 at the end of each day. I'm not sure I am adding enough bleach, but am doing what the pool calculator is telling me, provided I am using it right. It says my FC goal should be "2 to 6," and with the target set at 3 (which is where it was when I first opened it--I didn't change it) the amount of bleach it recommends I add is bringing me to the 3.4-3.6 range (it was 3.4 just now after being 3.6 last night). I assume it is all being eaten up by the sunlight since the FC Loss Test seemed OK, and the stabilizer hasn't dissolved enough to have any effect yet. Is this normal for a newly filled pool? Am I adding enough bleach? Should I raise the target on the pool calculator or is this sufficient?

The pH is holding steady at 7.4, and the TA at 70. I haven't tried retesting for CH yet, and testing for CYA seems useless until the stuff in the sock dissolves (right?). So, is there anything else I should be doing right now?

ETA: I should probably add that it's pretty hot here right now. Today's temp is predicted to be 97, and it's forecast to range anywhere from 94 to 101 over the next 10 days. The pool gets a full day of sun. The shallow end is shaded after about 3-4PM, but the deep end is in sun all day from about 7-8AM until about 6-7PM. Don't know if that makes any difference, but thought I should note it.

ETA again: One more question about the pool calculator... When I first open it, it says my FC Goal is "2 to 6" like I said above, but once I fill in my "Now" values and click "Calculate," the FC Goal changes to "1 to 3." Why is that? Is it because of the 0 CYA value? Or something else? Just want to be sure I'm getting the correct results.

your overnight fc loss is fine. your huge problem is you're letting the fc get to 0. you're supposed to shock if you let that happen. yes you're losing it to sunlight. wait a week after the cya dissolves to test. different things affect the recommended ranges for the calculator. if you change your cya level it will change the recommended fc level. I highly recommend you read pool-school/ pool chemistry section because it will answer these questions you have and will give you a much better understanding of pool chemistry which will make the calculator make more sense.

Hi reebok! Well, I've read that section, and read it again, and again. Maybe I'm missing something? Or maybe I just am not getting it yet. I didn't see anything that said to test for FC more than once a day, which I am doing each evening. Should I test twice a day, like again in the middle of the day, and add more then? Or should I raise the target from 3 to 4 or something even higher, so that I am putting more in each evening? If the calculator is supposed to recommend based on my current CYA level (which I tested for again yesterday, just to be sure, and got none), I've figured I was adding the correct amount based on that and was unsure what I should be doing different -- if I should change the target value or leave it where it is, or test more than once a day, or what. :?: Anyhow, I thought I was doing what the calculator said to do, so I am confused.

 

[Ohm_Boy]

You should be dosing your pool as if your CYA has dissolved already. We know that it hasn't, but after 24 hours from adding it, treat the pool as if it has the targeted amount in the water.

 

[WaterWoman]

You should be dosing your pool as if your CYA has dissolved already. We know that it hasn't, but after 24 hours from adding it, treat the pool as if it has the targeted amount in the water.

OK, thanks, Ohm-Boy. I'll try doing that.

ETA: Hmmm... Just tried it. It says my CYA goal should be "30 to 50," so I just tried entering as if it was at 40 in both the Now and Target columns. It immediately changes my FC goal from "2 to 6" to "3 to 7." The value in the Target column for FC remains at 3, however. Unless I change that, it tells me to put in exactly the same amount of bleach as I have been doing. So, am I supposed to manually change the Target figure to something else? And if so, what? Should I up that value from 3 to 4 and try that? Or go higher than 4 on the Target value? Sorry if I seem dense. I want to get this right.

 

[Ohm_Boy]

Right - it will adjust your 'goal' value. That is for your information. But you have to change the 'now' and 'target' values yourself and the calculator will tell you what you need to achieve that change.
Generally, I just go by the FC vs. CYA chart (click here) to determine a target level, which for a CYA of 40 should be 5ppm. You should be good at a range of 5 to 7. You're a bit on the low side right now running 3-4, but you're still safe.

As the CYA dissolves more, you'll lose less during the day. once it's been in there for a week or so, you can test and see how much you have.

 

[WaterWoman]

Right - it will adjust your 'goal' value. That is for your information. But you have to change the 'now' and 'target' values yourself and the calculator will tell you what you need to achieve that change.
Generally, I just go by the FC vs. CYA chart (click here) to determine a target level, which for a CYA of 40 should be 5ppm. You should be good at a range of 5 to 7. You're a bit on the low side right now running 3-4, but you're still safe.

As the CYA dissolves more, you'll lose less during the day. once it's been in there for a week or so, you can test and see how much you have.

OK, that helped. Thanks, Ohm_Boy. It's becoming a bit more clear in my mind now. (My brain sees numbers and generally freaks out. ) So, I should up the Target value from 3 to 5 and try that. Correct?

 

[reebok]

there are a few things you mentioned or asked about that are addressed in pool school, but I answered them anyway, I just thought it would help you to read or review it. you're kinda missing the boat on testing. it may not say test multiple times per day, but the whole point of the pool-school/chlorine_cya_chart_shock is the fc levels you must maintain 24/7 to avoid getting algae. and if you get all the way to 0, then you need to be testing more often for the next day or two at least. you also need to shock. this is the article that specifically states that about the 0 fc. pool-school/shocking_your_pool

 

[WaterWoman]

there are a few things you mentioned or asked about that are addressed in pool school, but I answered them anyway, I just thought it would help you to read or review it. you're kinda missing the boat on testing. it may not say test multiple times per day, but the whole point of the pool-school/chlorine_cya_chart_shock is the fc levels you must maintain 24/7 to avoid getting algae. and if you get all the way to 0, then you need to be testing more often for the next day or two at least. you also need to shock. this is the article that specifically states that about the 0 fc. pool-school/shocking_your_pool

Thanks. If it's not clear to me, then it's not clear to me. That's why I'm asking. I'm trying not to assume anything, and I AM reading everything, but I am also asking questions about what I don't understand. I'm very new to this, like less than a week. Pretty soon, I'll get it, hopefully as well as most of you. But for now, I need to ask questions in the hope that someone can help to make it more clear to me when I'm not understanding it.

 

[WaterWoman]

OK, I brought it up to shock level, as suggested. Other than the FC getting to zero briefly, I didn’t have any of the other reasons for doing it (pool appears to be algae-free, overnight FC loss tested two nights in a row is fine, and water looks good), but I did it anyway, to be sure.

I assumed my CYA was around 20. (The amount of stabilizer I put in should have brought it up to around there according to the pool calculator – I figured I’d add what I had on hand, which was 64 oz., re-test, then add more, as needed to reach 30-40 CYA – it’s almost all dissolved now, and the pH has gone from 7.4 to 7.2, so I figure it’s having an effect.) The Chlorine / CYA tables show an FC value of 10 for shock at 20 CYA, so, that’s what I did. I put in the amount of chlorine suggested by the pool calculator at dusk last night. The FC tested at 9.8 when I checked later. I figured that was close enough and left it there.

FC loss test this morning shows a loss of .4, which is the same reading I got yesterday morning as well.

The CC test gave me a reading of .2 (one drop turned it clear again).

And the water is looks clean and clear.

Continue to shock the rest of the day? Or can I let it fall to a more normal level now?

 

[WaterWoman]

I have questions about when to re-test for CYA, too. I know it takes 5-7 days to dissolve in the sock, and that it’s a waste to re-test for CYA while it’s still dissolving. And I know that Pool School says: “Solid stabilizer can take up to a week to fully register on the test, so don't retest your CYA level for a week after adding some.” But is that taking into account the time it takes to dissolve from the sock? Am I supposed to test again as soon as it’s all dissolved, or wait another week after that before testing for CYA again? This part is unclear to me. I’ll need to be adding more to reach the 30-40 mark, but don’t want to overdo it, so I want to be able to test it reliably before adding the final amount. Hope all that made sense.

 

[frustratedpoolmom]

5-7 days after it has finished dissolving.

So, to catch up....

I haven't checked this thread in a couple days. I thought it was just lots of folks raving about your transformation.

A couple of things a feel are worth mentioning.

I think you should just use the 10ml sample for .5 accuracy, no need to use the 25 ml sample as you are using more reagent than you need to.

Yes, your FC dropped to zero, but only briefly, I don't think you needed to shock. When in doubt about "when to shock" in situations like this, just bump it back up to normal levels, do an overnight test, if you lose more than 1ppm, then shock.

You made a mistake by not changing the value in the target box, to make it higher so that you would stay above 3 instead you were targeting 3. But that's a simple fix, you seem to understand that you now make your target 5-7 to keep you above 3 at all times.

You can let FC drop back to normal, and you can swim if you like. You can assume your CYA level is 20 if you feel certain you correctly calculated your target. I would go ahead and add enough to reach 40. You'll be fine.

 

[reebok]

Yes, your FC dropped to zero, but only briefly, I don't think you needed to shock. When in doubt about "when to shock" in situations like this, just bump it back up to normal levels, do an overnight test, if you lose more than 1ppm, then shock.

can the pool school article be changed to reflect this info? certainly a lot easier to do it this way, but there is no wiggle room according to how the article is written now.
pool-school/shocking_your_pool

 

[frustratedpoolmom]

That's a thought. I'll mention it to Jason.

 

[orthofish]

Hey Julie, Y'all have done a great job with that pool. Hang in there. I too was kinda overwhelmled when I started. You'll get it. It just takes repetition and reading. :study:

 

[JasonLion]

FC falling to zero means something is going wrong. In normal day to day operation, with correct amounts of chlorine being added, FC falling to zero almost always means algae, and shocking is required. But in other situations, depending on what the cause really is, it may only be necessary to raise FC to the high end of the target range. To be completely safe shocking is still a good idea. But if you have enough information to know exactly what is going on, it might not actually be required.

In this particular situation, FC is falling to zero because not enough chlorine is being added. Since there are no other indicators of algae, a full shock isn't required. But FC should be raised fairly high to be sure to wipe out any algae that might have gotten started while FC was low. From what I see here, that has already been done.

The instructions in Pool School are conservative, they recommend shocking so you can be sure that everything is going to be alright.

WaterWoman, the idea behind the normal FC range is that you raise the FC level up to the high end of the range once a day, so that it won't fall below the low end of the range over the next 24 hours. Over time you can adjust your target level, based on what actually happens in your pool. If FC is below the minimum the next day, you should aim for a higher FC target level. If FC is above the minimum the next day, you can aim for a slightly lower FC target level.

 

[WaterWoman]

5-7 days after it has finished dissolving.

So, to catch up....

I haven't checked this thread in a couple days. I thought it was just lots of folks raving about your transformation.

A couple of things a feel are worth mentioning.

I think you should just use the 10ml sample for .5 accuracy, no need to use the 25 ml sample as you are using more reagent than you need to.

Yes, your FC dropped to zero, but only briefly, I don't think you needed to shock. When in doubt about "when to shock" in situations like this, just bump it back up to normal levels, do an overnight test, if you lose more than 1ppm, then shock.

You made a mistake by not changing the value in the target box, to make it higher so that you would stay above 3 instead you were targeting 3. But that's a simple fix, you seem to understand that you now make your target 5-7 to keep you above 3 at all times.

You can let FC drop back to normal, and you can swim if you like. You can assume your CYA level is 20 if you feel certain you correctly calculated your target. I would go ahead and add enough to reach 40. You'll be fine.

OK, thanks, poolmom! I understand all of that. I didn't think I needed to shock, either, but had been told to do so (twice, I think?), and since no one said not to after 24 hours, I figured I'd better go head and do it. It shouldn't have hurt anything, though; right? I will switch to the 10mL sample (I did use up a lot of the reagent) and will monitor the FC to keep it above 3. It's getting easier to understand all of this as I go along, but it's a steep learning curve and a lot to absorb all at once. I know all of you have been where I am at some point, though, and I appreciate being able to come here and get advice. Thank you, again.

 

[WaterWoman]

Hey Julie, Y'all have done a great job with that pool. Hang in there. I too was kinda overwhelmled when I started. You'll get it. It just takes repetition and reading. :study:

Thanks, orthofish! Hey, you live in Northern Middle TN, eh? I used to live in Middle TN (DeKalb County, to be exact). It's beautiful country there!

 

[WaterWoman]

FC falling to zero means something is going wrong. In normal day to day operation, with correct amounts of chlorine being added, FC falling to zero almost always means algae, and shocking is required. But in other situations, depending on what the cause really is, it may only be necessary to raise FC to the high end of the target range. To be completely safe shocking is still a good idea. But if you have enough information to know exactly what is going on, it might not actually be required.

In this particular situation, FC is falling to zero because not enough chlorine is being added. Since there are no other indicators of algae, a full shock isn't required. But FC should be raised fairly high to be sure to wipe out any algae that might have gotten started while FC was low. From what I see here, that has already been done.

The instructions in Pool School are conservative, they recommend shocking so you can be sure that everything is going to be alright.

WaterWoman, the idea behind the normal FC range is that you raise the FC level up to the high end of the range once a day, so that it won't fall below the low end of the range over the next 24 hours. Over time you can adjust your target level, based on what actually happens in your pool. If FC is below the minimum the next day, you should aim for a higher FC target level. If FC is above the minimum the next day, you can aim for a slightly lower FC target level.

Thanks for the response here, Jason. Much appreciated. This is crystal clear to me. Thanks for clarifying. The FC hasn't fallen to zero except for right at the beginning when I was trying to figure all of this out, and that was only briefly. It's all getting much easier to understand, as I said. Thank you SO much for this forum.

 

[WaterWoman]

In the process of getting to understand how all of this works, I've been monitoring the FC level several times a day over the past couple of days -- at dawn, at around 11-noon, again at around 2-3 PM, and again at dusk. I did this because I wanted to have a better picture in my mind of what was actually happening in my pool. This has shown me that my greatest FC loss is in the morning, when the pool is receiving full sunlight. It is partially shaded after 3 PM, and the loss slows up at that point. So, it makes sense to me that the main culprit of FC loss for me is sunlight.