Cc slamming ?

[Jay5656]

I have been reading for the past week and I feel i have a good grasp on most of this . I do have one question
I have an indoor pool 15,000 gallon
Latest test
FC 2.5
CC 1.5
PH 7.6
ALK 100
CHL 250
CYA 0 ( INDOOR POOL )
My issue is the CC I have is my shock level for removal? Is it x cc or TC ? 15ppm or 25ppm or just build to 10ppm and hold ?
I have good ventilation so this is often not a problem MPS seem to have no result .
My plan is to slam with liquid bleach
Pool is perfect otherwise no smell crystal clear
Thank you
Jay

 

[pabeader]

Even for an indoor pool, we recommend at least 20ppm CYA. At 0 even 2-3 ppm FC is pretty harsh.

 

[Jay5656]

padebear,
Thank you I understand the CYA and I'm thinking about making that change. First I want to address the CC .
Thank you
Jay

 

[pabeader]

I think that the ccs may be coming from the lack of CYA. I don't have any "proof", but it's a general feeling I have from every thing I've read.

 

[Jay5656]

The CC in this case I'm pretty sure came from a brother in law who used the pool while I was away ( had a little party ) I have had this pool for over 3 years and have never had any issue with CC
I'm just trying to make sure I'm getting the correct slam level for their removal . If they come back I will address from there
Thank you
Jay

 

[JoyfulNoise]

The concept of breakpoint chlorination is a highly misunderstood topic and one full of bogus pool industry lore. You could read about it here -

Certified Pool Operator (CPO) training -- What is not taught

Is the formula for too high?

You should only need about 3X your CC level at most to remove CC's, so of your current measurement of 1.5ppm CC's, you'd need an FC level of 4.5ppm to consume all of the CCs. When a pool has zero CYA in it, we recommend that you use a shock level of chlorine at 10ppm FC max. That is all based on FC, not total chlorine. If you do not have your own test kit, you need to get either a K-2006 or TF-100 to test your water with. Pool store testing is too unreliable.

As for CYA and indoor pools, CYA has benefits beyond just protecting chlorine form UV as the industry mistakenly focuses on as the only benefit. CYA is a chlorine buffer, meaning it holds most of the chlorine you put in the water in reserve. Only about 5% of the remaining chlorine is in the form of active chlorine (hypochlorous acid and hypochlorite). This greatly reduces the harshness of chlorine in water and allows the chlorine to last longer. It also reduces the formation of the more irritating CCs (nitrogen trichloride) and favors the formation of the less harsh ones (monochlormaine). So, in both of those ways, CYA makes it a lot more comfortable to swim in a pool.

MPS is a supplemental oxidizer and can be useful in indoor pools to help oxidize bather waste without creating CCs in the process. Depending on the pool type (plaster versus vinyl), the added sulfate load may or may not be good. A better way to go would be to install an inline UV system if you don't have one. Since outdoor pools get plenty of UV from the sun, those systems don't add any benefit to an outdoor pool. To an indoor pool, a UV system can work just as well as adding MPS by oxidizing certain types of bather waste and reducing the formation of CCs.

 

[JoyfulNoise]

Oh, in case it wasn't clear, you should target 10ppm FC and hold it there until the CCs get to zero. If the pool is covered at all, you may need to uncover it and run the ventilation system to pull in fresh air. Do not go swimming again until the FC levels have come down to 3ppm or less.

 

[Jay5656]

Joyfulnoise ,
Thank you . I'm reading all I can and will be making changes I do have a full taylor test kit so I trust my readings . Ill look into the UV system . I'm off to Slam I will post results
Thank you
Jay

 

[Jay5656]

pool test
FC 10.5
CC 2.0
ON MY WAY

 

[JoyfulNoise]

You want to keep the FC elevated and held at 10ppm. It's ok to overshoot a little bit. The better you are at maintaining the 10ppm level, the faster it will go. Measure frequently in the first 24 hours so you know when you have dipped below 10ppm. That will help you to maintain the shock level.

By the way, can you update/add your pool surface type and equipment in your signature line. It helps a lot to know what we're dealing with.




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