Great job on the tactical refill. 
We'll look forward to seeing your new CYA numbers.
We'll look forward to seeing your new CYA numbers.
This pool is killing me
- Thread starter Brettkarren
- Start date
So I wanted to do a n update and get some opinions
After the partial drain I was able to do all my tests again
FC: 2
CC: 0
TA: 130
PH: 7.5
CH: 350
CYA: 45* see note
First things first. I did my first CYA test and I think i'm off. I ran it a few times and got anywhere from 70-90. I had 3 different pool stores run it and they all got between 40-50. one of the stores is a guy I trust. He is kind of a geek like the guys on this site and even suggests the bleach method for chlorination. Ive read up on the CYA test and I feel like i'm not obscuring the black dot enough. So I went with the pool store reading for now (I know we don't like that here).
secondly, Since I have a slight mustard algae bloom on the shady walls of my pool I decided to slam it at the mustard level. I purchased 10% bleach from home depot. It was stored inside and the production date was may 10 2017. So it should be fresh. I began the process just after dark. I used the pool math calc to add enough to hopefully get to 27ppm. I tested this morning just at sunrise and got an FC of 18. I calculated the amount of chlorine needed to get back to 27 and added that this morning.
A few questions:
1. how soon after beginning the slam process can i retest to see if I actually got the FC to the slam level?
2. I didn't want to add 60 drops of reagent so I did a little dilution with RO water. 10ml pool water, 30ml RO water (tested and no chlorine present). mixed the sample and used 10ml of the new solution for the FAS-DPD test. took 9 drops to clear the color. 9*4*.5=18ppm. Does that math workout?
The areas that have a hint of yellow are around the skimmer intake, the pool light, the main drain. Do I have to get downt there and scrub it with a toothbrush or something? or will the chemicals knock it out if I maintain the proper FC level?
So I basically want to make sure I'm on the right track. Any suggestions or corrections are welcome. Thank you.
After the partial drain I was able to do all my tests again
FC: 2
CC: 0
TA: 130
PH: 7.5
CH: 350
CYA: 45* see note
First things first. I did my first CYA test and I think i'm off. I ran it a few times and got anywhere from 70-90. I had 3 different pool stores run it and they all got between 40-50. one of the stores is a guy I trust. He is kind of a geek like the guys on this site and even suggests the bleach method for chlorination. Ive read up on the CYA test and I feel like i'm not obscuring the black dot enough. So I went with the pool store reading for now (I know we don't like that here).
secondly, Since I have a slight mustard algae bloom on the shady walls of my pool I decided to slam it at the mustard level. I purchased 10% bleach from home depot. It was stored inside and the production date was may 10 2017. So it should be fresh. I began the process just after dark. I used the pool math calc to add enough to hopefully get to 27ppm. I tested this morning just at sunrise and got an FC of 18. I calculated the amount of chlorine needed to get back to 27 and added that this morning.
A few questions:
1. how soon after beginning the slam process can i retest to see if I actually got the FC to the slam level?
2. I didn't want to add 60 drops of reagent so I did a little dilution with RO water. 10ml pool water, 30ml RO water (tested and no chlorine present). mixed the sample and used 10ml of the new solution for the FAS-DPD test. took 9 drops to clear the color. 9*4*.5=18ppm. Does that math workout?
The areas that have a hint of yellow are around the skimmer intake, the pool light, the main drain. Do I have to get downt there and scrub it with a toothbrush or something? or will the chemicals knock it out if I maintain the proper FC level?
So I basically want to make sure I'm on the right track. Any suggestions or corrections are welcome. Thank you.
My understanding of slamming with mustard algae is you slam normal levels and at end of SLAM is when you raise to mustard algae level for 24 hours.
When testing your CYA, take it with back to sun. Put tube at waste level and body shading the tube. Fill it up in increments of 10 and then look. Don't stare the whole time. Do this and trust your own results. I'm sure pool store guy is trustworthy, but he isn't testing in natural light under the sun.
Also, always round your CYA up so for example, 45 is actually 50.
You can test FC levels 15-30minutes after you add your chlorine.
When testing your CYA, take it with back to sun. Put tube at waste level and body shading the tube. Fill it up in increments of 10 and then look. Don't stare the whole time. Do this and trust your own results. I'm sure pool store guy is trustworthy, but he isn't testing in natural light under the sun.
Also, always round your CYA up so for example, 45 is actually 50.
You can test FC levels 15-30minutes after you add your chlorine.
spin has it down pat. Remember if you're doing the 10 point CYA glance method to always round up to the higher CYA. E.g. if you can see the dot at 50, and you raise it to 40 and can't see the dot, you assume it's 50 since you don't know where in between 40 and 50 it disappeared.
First, retest CYA in bright sunlight as spin outlined. Double check that store number. Once you're confident about your CYA level, get the FC to regular SLAM. Once your SLAM is complete, then raise it to mustard levels. Don't forget to wash all towels, swim suits, and spray/wipe everything that has been used in the pool with a bleach solution.
Not sure how i missed the instructions for mustard. thanks for the correction. I reread it and it looks like i'm going to have to take the light out of the housing and brush everything. that sucks. I plan on bleaching all pool items as well
how about the dilution math? did i do it right?
i'll continue to work on the CYA test.
For testing during SLAM (not for OCLT, just for your FC checks), use a 5ml sample of water. Each drop represents 1FC. Make sure you're as exact as possible as the error rate goes up with such a small water sample. That should save you quite a bit of reagent.
I got home and tested this afternoon again.
FC:8
The short history is that I slammed up to 27 last night (didn't realize the correct protocol to do a normal slam before mustard slam)
This morning it was 18. added enough to get to 27 again (once again still didn't realize correct protocol)
now we are at 8 again.
The pool never was loaded with algae. just some on the walls its just been tenacious.
The questions is: this seems like I am going through this stuff chlorine like crazy.
Do I need to increase my CYA pronto or just keep adding chlorine? *current CYA 45
FC:8
The short history is that I slammed up to 27 last night (didn't realize the correct protocol to do a normal slam before mustard slam)
This morning it was 18. added enough to get to 27 again (once again still didn't realize correct protocol)
now we are at 8 again.
The pool never was loaded with algae. just some on the walls its just been tenacious.
The questions is: this seems like I am going through this stuff chlorine like crazy.
Do I need to increase my CYA pronto or just keep adding chlorine? *current CYA 45
Your CYA is 50, we always round up if your tube is over the 40 mark. Dose accordingly. Once you know your pool is entirely free of cooties you should raise that CYA up a bit for your hot sunny AZ weather.
Maddie
Maddie
Our sun can take a pool from mustard slam to regular FC range at a particular CYA in under two days. I've seen it myself.
Have you performed an OCLT lately? Pool School - Perform the Overnight FC Loss Test (OCLT)
Have you performed an OCLT lately? Pool School - Perform the Overnight FC Loss Test (OCLT)
I did an OCLT last night
FC at 10pm last night was 13
FC at 6 Am this morning was still 13.
CC was 0
Pool looks good now.
But I guess i need to continue and actually do the mustard slam now. Not looking forward to trying to keep it up to FC: 27 for 24hrs in 117 degree heat and full sun.
- May 3, 2014
- 58,303
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Cooler of beverage and some shade. May have to test/dose about every half hour to keep up with the loss at elevated FC.
Have fun!
Have fun!
Wait. For real? I need to test and replenish every 30 minutes?
Thats a ton of testing and a ton of chlorine
Also, I was wondering if I still need to slam for mustard even if i don't have any FC loss over night. Wouldn't that mean there are no organics left? What am i killing if there are no organics left?
- May 3, 2014
- 58,303
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
At an elevated FC without the corresponding higher CYA your loss to the sun shining on the pool is much greater. You may not have to add much chlorine each time, but if you want to keep at Mustard levels, you will need to be on top of it.
As far as your last question - not sure. I think the theory is Mustard Algae is somewhat elusive. But up to you.
As far as your last question - not sure. I think the theory is Mustard Algae is somewhat elusive. But up to you.
Update with questions
I completed the slam and the extended mustard slam. pool looks great, OCLT was good, CC: 0, CYA 50 (from before slam. haven't tested since)
During the day, I have about a 10ppm fc loss
That would suggest I would have to bump up my CYA right? Or should I be monitoring this for a longer period of time. Ive done two days now The morning after the mustard shock I was at FC: 18, by evening I was at 8.
1. What is the process to figure out what my CYA level should be for my pool? (is there a specific chlorine loss per day that is the norm?) I can't be adding 10 ppm of chlorine per day
2. How does one increase CYA? use the extra trichlor tabs i have over a period of time or just buy stabilizer?
I completed the slam and the extended mustard slam. pool looks great, OCLT was good, CC: 0, CYA 50 (from before slam. haven't tested since)
During the day, I have about a 10ppm fc loss
That would suggest I would have to bump up my CYA right? Or should I be monitoring this for a longer period of time. Ive done two days now The morning after the mustard shock I was at FC: 18, by evening I was at 8.
1. What is the process to figure out what my CYA level should be for my pool? (is there a specific chlorine loss per day that is the norm?) I can't be adding 10 ppm of chlorine per day
2. How does one increase CYA? use the extra trichlor tabs i have over a period of time or just buy stabilizer?
High FC and low CYA is a losing combination. FC loss to sunlight is a percentage, not a fixed ppm, so the higher your FC, the more you lose.
For Arizona, I'd target 50 CYA minimum. If you overshoot by accident, 60 is still not outrageous for where you live, so long as you maintain proper FC/CYA ratio.
For Arizona, I'd target 50 CYA minimum. If you overshoot by accident, 60 is still not outrageous for where you live, so long as you maintain proper FC/CYA ratio.
1. Most pools lose about 2-4ppm per day without any swimmers in them. If you're seeing 10ppm loss and your OCLT is good (I see from your post above it was), you may want to raise your CYA. Many folks in our area run 50-60ppm. Make sure you increase your FC levels to compensate.
2. If you're only going up 10ppm or so, you could consider using dichlor to do it. If you're going up more than that, you may want to consider buying stabilizer and raising it separately. You can usually get 4lbs of granular stabilizer for about $13-15.
2. If you're only going up 10ppm or so, you could consider using dichlor to do it. If you're going up more than that, you may want to consider buying stabilizer and raising it separately. You can usually get 4lbs of granular stabilizer for about $13-15.
i had a few questions but they were answered as i was writing. can't seem to delete this post. so disregard.
2-3 per day. Maybe 4 with intense sun and a lot of swimmers.
Study on this awhile. It shows the half-life of FC at various CYA levels. You will see for yourself that you'll lose about half of whatever in less than 7 hours at 50 CYA. So if you double the FC, you'll lose twice as much. That's why you can't just figure at 3 per day, you can add 9 and ignore it for the next three days.
2-3 per day. Maybe 4 with intense sun and a lot of swimmers.
Study on this awhile. It shows the half-life of FC at various CYA levels. You will see for yourself that you'll lose about half of whatever in less than 7 hours at 50 CYA. So if you double the FC, you'll lose twice as much. That's why you can't just figure at 3 per day, you can add 9 and ignore it for the next three days.
OOOoh! graphs. now you are speaking my language. I'll take a look. I do see what you are saying though. 1 standard number doesn't fit all scenarios. thanks.