First SLAM!

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C

cmderrico

0
May 21, 2016
11
Lovettsville, Virginia
We had an algae bloem start a week ago. After several rounds of advice from the pool $tore, we decided to take matters into our own hands. They could only recommend 2 bags of shock and algaecide to help solve the problem. Another pool 'fixer' recommended a phosphate killer treatment, which we did not do. Needless to say, the pool $tore advice was not helping, as the pool turned more green each day. I had flipped through the pages of the Pool School a bit last year and after further study this weekend now fully understand the methods and PoolMath. Thank you TFP!

This is our current reading from the test kit which arrived today. With CYA over 100, FC needs to be at 39 according to PoolMath. We've had a lot of rain so will slowly drain the pool to level and to reduce CYA. We've been pouring in 2 gallons of liquid chlorine for the past two mornings, as I learned from another post while studying and waiting for a test kit. I put another 4 gallons into pool tonight, per PoolMath. Even with only 2 gallons per day for the past two days, the color is getting slightly better looking at these photos. Let's see how it looks tomorrow after the 4 gallons tonight.

Thanks TFP and more updates to come!
 
Welcome! You are way ahead by having a good test kit already!

You need to do an extended CYA test to see how high over 100 you are. See Pool School - CYA

You need to drain water. But with a vinyl liner you can only go down to leaving 1' of water remaining in the shallow end. So depending on how high your CYA, this may take multiple drains.

Ponder over things and get back with us on the direction you plan to go.

Take care.
 
Thank you, mknauss! I did the normal test twice and the extended CYA test (step #8). The extended test was right at 50 (x2 = 100). Ironically, I have a leak in the liner somewhere so my pool drains about an inch per day. My town's water rate is $104 per 6000 gallons. Draining the pool a few times - even with the help of two small wells on the property - I may be paying over $300. 4 gallons liquid chlorine (10%) per day at $21 for 5 days is $105. I need to test the FC levels on Mon morning and afternoon to see if 4-6 gallons per day will be enough to keep it at shock level. All input welcome!
 
Amazing how expensive water is in places. I pay $2.70 per 1000 gallons -----

Good luck. Trying to do a SLAM at this level will be challenging.

Take care.
 
Day 8 of SLAM. I thought we'd be swimming today. Unfortunately, pool is still cloudy in deep end. Latest test readings and photos are here: https://photos.app.goo.gl/thbFp6N0RpwkCR6q1.

I did an OCLT last night and FC went from 25 to 19 overnight, so we still have organisms in the water. I put 1 gallon chlorine (8.25%) in this morning even though PoolMath suggested ~3 cups. We have a very bright sunny day after several days of heavy rain in the DC area. I will do an OCLT tonight.
 
Why are you not swimming? Safe up to shock level based on your CYA. You will not know the difference.

Take care.

You do need to be able to see the bottom of the deep end. From your picture it looks OK but check that first.
 
Thanks, Marty! I'm reading several posts from the 'experts' that state it's safe to swim at or slightly above shock level. One of them showed a comparison to a public pool - see quote below. I may not be able to convince the wife in a one minute explanation. :)

jblizzle said:
sshhhhhhhh ... it is still safe over shock level, within reason ....

The higher your FC relative to your CYA, the more active chlorine in the water and thus the more harsh it is to your skin, hair, swimsuit, etc.

Check out this chart that shows the active level as a function of CYA and FC. You can draw your own conclusions about what is a "safe level" of FC when you remember that a public pool with 0 CYA often has a FC up around 2ppm.
http://troublefreepool.com/~richardfalk/pool/HOCl.htm

I will give an example:
That public pool would have an active chlorine level of around 1.00ppm
At CYA 50, normal FC level is 6, giving an active chlorine level of 0.05ppm (1/20th as harsh as the public pool)
At CYA 50, shock level is 20, so active chlorine level is 0.30ppm (1/3 as harsh as the public pool)
At CYA 50, to match the active level in the public pool, the FC would need to be up around 30ppm probably.
Click to expand...
 

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Update: we are back swimming today. Water is bright blue and clear. OCLT is showing no loss at night. FC coming down to normal levels. Thanks, Marty!
52b986daf64052ef329390d36275a46f.jpg
 
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