Here is a link for more info about the overnight test:
Pool School - Perform the Overnight FC Loss Test (OCLT)
Pool School - Perform the Overnight FC Loss Test (OCLT)
Chlorine high, water getting greener
- Thread starter Erika Riley
- Start date
Woohoo! Got lucky? Yayyyyyy 
!! I have to admit, the test kit was daunting at first, but yes, it was kinda fun!! I just posted pics...will try again
!! I have to admit, the test kit was daunting at first, but yes, it was kinda fun!! I just posted pics...will try again
I see them!!! You are WELL on your way to a clear pool! SWEET! Okay I would not bother doing the OCLT yet. You are still a little ways from it.
You need to SLAM the pool. Here is a link to it:
Pool School - SLAM - Shock Level And Maintain
The most important part of the SLAM is the M=maintain as maintain the FC at the SLAM level for your CYA. Look for the chart inside the SLAM link.
Take and share a picture a day looking down at your pretty steps. That will help us and you see it clear!
You need to SLAM the pool. Here is a link to it:
Pool School - SLAM - Shock Level And Maintain
The most important part of the SLAM is the M=maintain as maintain the FC at the SLAM level for your CYA. Look for the chart inside the SLAM link.
Take and share a picture a day looking down at your pretty steps. That will help us and you see it clear!
Woohoo! Got lucky? Yayyyyyy
that is as green as it gets unless it was green LED pool light but then again it's too cloudy. Please measure your overnight FC loss just in case although it looks like you'll need to SLAM it. Is your pump working fine and filter clean? You'll need their help pretty soon. Please buy about 20 gal of 8.25% bleach or higher concentration if you can find it.
All righty, I'll get to SLAMming!I see them!!! You are WELL on your way to a clear pool! SWEET! Okay I would not bother doing the OCLT yet. You are still a little ways from it.
You need to SLAM the pool. Here is a link to it:
Pool School - SLAM - Shock Level And Maintain
The most important part of the SLAM is the M=maintain as maintain the FC at the SLAM level for your CYA. Look for the chart inside the SLAM link.
Take and share a picture a day looking down at your pretty steps. That will help us and you see it clear!
With a CYA of 50 I see the chart says I should be at FC 20. I will make sure I start with clean filters, add liquid bleach and then test to see where it's at, and add more if necessary to get to FC 20? I'm assuming I need to significantly up the amount of bleach from the 1 gallon that I have been doing? Is that amount a guess or is there a chart for recommended amounts?Is there a best time of day to brush?
So many questions
Thank you!
You can also try to add 1/3- 1/4 gal of 31.4% MA to bring your pH slightly down. Just don't add it with bleach at the same time, keep them 30 min apart.
I'd add 4 gal of bleach to start SLAM. It's slightly over 20 but with that color it will be down in no time. Please monitor FC every 2 hrs at the beginning, it tends to fall quickly. Run pump 24/7 and brush everything whenever you can.
During SLAM all you need to monitor is FC only, the rest can wait and pH will be simply invalid at FC > 10, don't even bother. You can use 5 mL sample to get 1 drop = 1 ppm FC resolution as at this levels 0.5 ppm does not matter but you'll save on reagent.
Take 'progress' pictures over stairs at the same time/lighting to see how it goes. Good luck!
Think it would make a difference to add the MA for the pH right now? I'm just wondering, if the pH will be invalid during a SLAM maybe I should hold off on that? I won't be able to monitor FC every 2 hours for the next two days (that office/work thing) but I will get a reading in the AM and can get a couple in the PM.
Really appreciate your input!! thank you
Think it would make a difference to add the MA for the pH right now? I'm just wondering, if the pH will be invalid during a SLAM maybe I should hold off on that? I won't be able to monitor FC every 2 hours for the next two days (that office/work thing) but I will get a reading in the AM and can get a couple in the PM.
Really appreciate your input!! thank you
I believe lowering pH is one of the recommendations prior to SLAM, it makes the process more efficient. The fact you won't be able to monitor it doesn't change much- it will still be there at the end. FC is the only parameter which is actively changing during SLAM.
You got accurate values of pH & TA so it allowed me to simply enter them into PoolMath to estimate how much MA would it take to bring pH down to the desired level. That estimate is usually very close as long as input data are correct. Don't worry, pH is one of the easiest parameters to adjust in both directions.
Yes - I sure can do the evening/morning FC test.
I'm on city water, but not sure of the iron content. I've never heard anything negative about it?
Will post pics momentarily. Sun is setting so it was hard to capture. If they aren't helpful, I'll try again tomorrow afternoon for some better ones!
THANKS!
- - - Updated - - -
Awesome! Thanks for the tip
The over night FC is 8.5ppm (last night 8.4ppm) and the CC is .5ppm (last night.4ppm). I used 10ml water this morning, used 25ml last night - could this account for such a minor change/increase? I also shut the pump off for the first time in 5 days.
I have added 3 gallons chlorine bleach, brushed, have clean filters and pump running.
Will be away from the pool several hours now, but will take another FC test and post pics! Fingers crossed for any improvement
The over night FC is 8.5ppm (last night 8.4ppm) and the CC is .5ppm (last night.4ppm). I used 10ml water this morning, used 25ml last night - could this account for such a minor change/increase? I also shut the pump off for the first time in 5 days.
I have added 3 gallons chlorine bleach, brushed, have clean filters and pump running.
Will be away from the pool several hours now, but will take another FC test and post pics! Fingers crossed for any improvement
So is this correct: last night FC=8.4 ppm (25mL), this morning FC=8.5 ppm (10mL) and no chlorine additions in between? If so- do you have SWG / chlorine tabs dispenser / any other chlorine source in the pool?
I'm not so worried about 0.1 ppm 'increase' as the test is not that accurate to begin with (it is accurate enough for pool care purposes) but with pool this green usual drop in FC is 5-6 ppm so you should've been seeing FC about 3ppm max this morning and the test is more than accurate to catch that. Something doesn't add up.
FC naturally drops over day due to Sun UV radiation, that's why FC loss test is performed over night. Try to take 2 FC readings for overnight loss test in as close as possible conditions: the same sample size, from the same spot in the pool, at least 1 hr after last chlorine addition and don't add any chemicals between first and second FC measurements.
If you added those 3 gal after morning FC measurement then it should put your pool at SLAM level of 21.5 ppm, please let us know how it progresses. In algae free pool the daily loss from the Sun is about 2 ppm so if it drops below 20 please bring it up with bleach.
You shouldn't do an OCLT until the water is crystal clear. I wouldn't bother doing an OCLT for now so that you can save on your reagents as you might run out of them before your finish your SLAM.
Also, to save on FC reagent you can just test for FC and not worry about the CCs for the moment.
Don't adjust PH for now as a 7.5 isn't far enough from the recommended 7.2 to make a huge difference.
Also, to save on FC reagent you can just test for FC and not worry about the CCs for the moment.
Don't adjust PH for now as a 7.5 isn't far enough from the recommended 7.2 to make a huge difference.
Agreed. The OCLT is to tell if there is organic matter in your water. The green algae is an obvious sign that there is organic matter in your pool.
You should be running you pump/filter 24/7 for the duration of the SLAM, including the OCLT. That, and using different sample sizes is going to skew the results.