New tests results completed - few questions

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steveb21

steveb21

0
Mar 6, 2017
265
United Kingdom, England.
I turned a black swamp into a clear pool a few months back after completing a 40+ day SLAM.

At the time my CYA was 60. I have been maintaining FC of between 5-9 for the last few months. Pool has hardly been used in that time and i was averaging a loss of 3ppm (900ml liquid chlorine) FC in 24 hours.

A few days ago i noticed my pH had risen to 8.0 so i have been gradually reducing that down.

Just completed test results

FC 8
CC 0
pH 7.2
CH 280 (aim is to get this to around 350)
TA 80 (was 100 before i started reducing pH)
CYA 40 (did 5 tests and i average 35, i take it i round it up to 40?)
CSI -5.2 (Less than -0.6 is suggestive of problems for plaster, tile, stone, and pebble pools. - What do i need to do to reduce this?)


Questions,
*What is/are the reason for my CYA to drop? Have had a bit of rain last few weeks, which i understand could be the reason pH has increased but im not sure about the CYA?

*Since dropping my pH i have noticed my FC usage has decrease over 24 hours. Is this normal?

* Am i correct in thinking as i have been targeting FC of 9 when (as linked to CYA of 40) it should have been FC of 7 that this could be the reason why more FC was being used?

*So to maintain, min FC is 3, target is 5-7. Do I start with the new figures from now or should i increase CYA? (i have some pucks which the previous owners left behind).
 
Steve,

I see that no one has answered your question yet, so I'll give it a shot...

I'm not sure why your CYA dropped, but CYA will go down a little on its own and splash out and a little leak could also cause it to decrease.. The test itself is +/- 10 ppm so if you combine all that, and it would not take much to go from 60 to 40..

pH has little effect on FC usage, but you really can't tell anything in a 24 hours.. There are so many variables, like the temperature, the amount of sun, and the amount of FC vs. the CYA, that could effect the readings.

It is true that if you have your FC a lot higher then it needs to be, that the additional FC will burn off quicker.

If you don't have a saltwater pool, then a CYA of 40 is just fine.. I would leave it right there.

Thanks for posting,

Jim R.
 
Should have the CH Increaser tomorrow so will get the CH raised to 350-400.

It has been 3 days since adjustments and my FC usage has been 1ppm loss in each 24 hour period covering the 3 days - Current reading is 6.

As i said before i was losing 3ppm of FC in 24 hours before i made the adjustments. Just trying to work out whats going on.
 
Up to 4ppm of FC loss in 24 hours is considered normal loss, so your FC loss has been fine. FC loss will change with different factors including weather, amount of bathers in the pool, using a cover etc. CYA of 40 is good if you don't have a SWG, target your FC at 7ppm.
 
If you're only losing 1ppm FC each day, consider yourself lucky. I lose 3-4ppm each day, mainly because my pool gets full sun from sun up to sun down.

You'll lose FC period, sometimes at a slow rate, sometimes faster, depending largely on how much sun your pool gets and how much organics get into your pool, whether that's leaves, bugs, or skin cells and oils from people. Too much FC loss each day means you need to raise your CYA up a little to slow down the loss, but I wouldn't worry if you think you're not losing enough. That just means your pool is very clean and there's nothing for the chlorine to react with.
 
yep, im pretty pleased that my Chlorine useage has dropped... but just wondered why.

Last 24 hours i have recorded no FC loss, can that even be possible? In 5 days i have had a loss of just 3.5 FC. I will be pretty happy if its stays that way but just making sure nothing else could be effecting the results.

12/08/2017
14:00
8
13/08/2017
16:00
7
14/08/2017
16:00
6
15/08/2017
16:00
4.5
16/08/2017
16:00
4.5

My CC results have been 0
 
steveb21 said:
yep, im pretty pleased that my Chlorine useage has dropped... but just wondered why.

Last 24 hours i have recorded no FC loss, can that even be possible? In 5 days i have had a loss of just 3.5 FC. I will be pretty happy if its stays that way but just making sure nothing else could be effecting the results.

12/08/2017
14:00
8
13/08/2017
16:00
7
14/08/2017
16:00
6
15/08/2017
16:00
4.5
16/08/2017
16:00
4.5

My CC results have been 0
Click to expand...

Does your pool get any sun at all?
 
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