SLAMing question

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836byK9

836byK9

0
Apr 7, 2014
17
Central California
Hello everyone. I noticed my pool was starting to loose quite a bit of FC per day so a couple days ago I performed the OCLT. (I would add enough chlorine to bring the FC up to 6ppm in the evening when everyone was finished swimming. By the next afternoon when I would test the FC it would be down to around 1ppm or less.) The Results from the OCLT were a 2ppm loss from about 8:30pm to 5:00am. It's worth noting that no one was in the pool the day I ran this test. The pump ran till 10pm and runs for 3 hours every night. My water appears to be very clear and with my weekly tests my CC is less than 0.5ppm (it barely turns pink which I attributed to my 4 kids living in the pool).

The only issues I've had with the pool was with the sand in the filter. I have a 16" Intex sand filter and used Clorox sand. Apparently I did not do enough research prior to buying it. I've been reading that the Intex filters do not like the Clorox sand since some of it tends to be smaller than the recommended size and slips through the laterals and into the pool. The other thing I've noticed is that the tube from the Intex skimmer to the port in the pool had a small amount of algae. I didn't even notice it at first until I starting giving everything a closer look. The other hoses leading from the pool to the filter are clear tubing also but they do not have any signs of algae.

Yesterday I started the SLAM process around 5pm and brought the FC up to 16ppm. pH was at 7.4 and CYA at 50. The rest of the numbers are within range also. Went out this morning around 6am and found the FC to be at 10ppm. Added additional chlorine to bring the levels back up and gave the liner another scrubbing. Checked again at noon and it was down to 12ppm. Again added more chlorine. Tested again at 3pm and is was down to 10ppm. I backwashed the filter, which I also did yesterday, and a fair amount of green came out of the filter. Rinsed and added more chlorine.

I'm new to pools since we've only had this one for a little over a month now. The information here has been awesome but the irregularities in the numbers have me a little confused. I have new sand to put in the filter but wanted to wait until I get the OCLT under control before I change out the sand and build my PVC plumbing. I know the California sun doesn't help with the FC loss but it just seems a bit off to me.

Thanks in advance for the help!

Doug
 
You are going to lose some FC to the summer sun. Dose as often as you can to keep your FC at SLAM level for your CYA, especially after sunset.
If you are not already, use the 10ml test to save reagent. Avoid running out and order more reagent well in advance.
You will begin to see a reduction in FC loss as you lower the algae population. Follow the SLAM to the "T". SLAM Process
 
Lemonred34 said:
With a CYA of 50, your FC SLAM target should be 20 not 16. What has been your average loss of FC ppm prior to this? Are you confident in your CYA reading?
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I was looking at the Pool Math app when I placed my values and the app recommended 16. I'll bump it up. I just checked my CYA again about an hour ago and I lose the black dot just above the 50 mark. Edit: Just checked the app again and the CYA amount was set to 40. :confused:

Oly said:
You are going to lose some FC to the summer sun. Dose as often as you can to keep your FC at SLAM level for your CYA, especially after sunset.
If you are not already, use the 10ml test to save reagent. Avoid running out and order more reagent well in advance.
You will begin to see a reduction in FC loss as you lower the algae population. Follow the SLAM to the "T". SLAM Process
Click to expand...
I've been using the 10ml test since week 1. I guess what's been bothering me the most is just that I haven't seen any algae and the liner hasn't been slippery or shown any other tale tale signs of growth.
 
Are you using the full sun with your back turned method? Also after you mix the pool water with the cya solution let it sit until it’s room tempature and mix one more time before testing. If your black dot disappears between the 50-60 line assume 60. If it disappears between 50-40 line assume 40.
 
Lemonred34 said:
Are you using the full sun with your back turned method? Also after you mix the pool water with the cya solution let it sit until it’s room tempature and mix one more time before testing. If your black dot disappears between the 50-60 line assume 60. If it disappears between 50-40 line assume 40.
Click to expand...
I've been checking it on my covered patio and the east wall of the house blocks a lot of the sun from the table. Should I be looking at it in the sun? Its a glass table so its still getting light from the underside. As far as letting the solution set I leave it for about a minute then check.
 

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Lemonred34 said:
Search extended cya testing in the search bar then choose “google search” and it should be the first one to show up. Sorry idk how to link that one here.
Click to expand...
www.troublefreepool.com

CYA - Cyanuric Acid Test

Cyanuric Acid (CYA) is the chemical name for what is commonly referred to as Stabilizer … Read more…
www.troublefreepool.com www.troublefreepool.com
 
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You may be backwashing too often. Let your filter pressure rise by 25% over clean pressure before you back wash.
 
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If your black dot disappears between the 50-60 line assume 60. If it disappears between 50-40 line assume 40.
[/QUOTE]
I'm not sure I understand what your saying. As I have been reading thus far I've always understood in between lines reads to the higher value. Please explain why you read 60 when it's between 50-60 but between 40-50 you only except a value of 40.
 
wireform said:
If your black dot disappears between the 50-60 line assume 60. If it disappears between 50-40 line assume 40.
Click to expand...
I'm not sure I understand what your saying. As I have been reading thus far I've always understood in between lines reads to the higher value. Please explain why you read 60 when it's between 50-60 but between 40-50 you only except a value of 40.
[/QUOTE]
Yes higher value. It was a typo. Thank you for catching it.
 

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