Pucks and Jugs

[Mattyssox]

Hello,

You guys helped me last year so I figured I would pick your brain again.

2 years ago I bought a mother load of 3 inch pucks. Last year, I began using the bleach method. The problem now is that I have a huge tub of pucks sitting in the pool shed. As you guys know, these are expensive. I'm aware that the pucks can/will raise CYA levels. My CYA is currently at about 45 (after dumping some stabilizer in a week ago).

My question is this: If I use a puck every couple days in the pool, will I significantly raise my CYA level? to the point where I will need way too much bleach to shock the pool? I'm trying to understand how much CYA each puck will really increase my pool by.

 

[Puffin]

You should be able to use the pool calc to figure out how many PPM one puck will raise your CYA

At the bottom, put in the weight of the puck (I think they're 8oz) then select trichor.

 

[Mattyssox]

Ok. So using that calculation it says it will raise it by 1. With that said, my pool is open for about 3-3.5 months. So this is about 15 weeks. Assuming about 2 pucks per week, I'd raise my CYA by 30 for the season. Bringing my total to about 75 for the CYA.

This is not in danger, but it is on the high side. I also wonder what the impact of backwashing has to this. I do backwash when when the PSI gets gets about 5-10 higher than normal.

Thoughts on this ? Recommendations?

 

[2001rotax800]

Are your pucks Dichlor or Trichlor? That will make a difference of how much CYA your puck is adding to your water. There is a thread on here that explains in great detail. To sum it up, it does not add a significant amount, but over time it does build up.

 

[anonapersona]

When you backwash you are dumping water and you need to refill that amount with tap water which has no CYA. So backwashing is helping to keep CYA lower.

Probably best to keep a log of your CYA levels, then estimate when it will have risen by some amount large enough to see on a test. Given the test is good to +/-10 or 15, when you have used 15 pucks, or maybe 20, retest CYA to see where you really are.

 

[chem geek]

Are your pucks Dichlor or Trichlor?

There are no [EDIT] slow-dissolving [END-EDIT] Dichlor pucks. Only Trichlor and sometimes Cal-Hypo.

For every 10 ppm FC added by Trichlor, it also increases CYA by 6 ppm. So with a fairly typical 2 ppm FC per day chlorine usage, using only Trichlor pucks would increase CYA by over 35 ppm per month.

 

[diverman57]

all this being said, i have to wonder why you added cya when you had pucks to use up. i always
keep my cya on the low side (30 or so), just so i can use pucks when i'm away on vacation. over the
course of the summer my cya will usually rise to 45 or 50 and i can use up the pucks i have.

 

[Mattyssox]

yeah..well I'll stop using them. I guess it was a dummy move on my part.