This morning's test results

[dzedaddy]

Happy Saturday everyone!

FC = 4.0
CC = <0.5
pH = 7.4
TA = 75
CH = 210
CYA = 55

Seems like my CYA has dropped some over the past few weeks, is this typical?

It also looks like I have to run my SWG and pump close to 16 hours a day to keep the FC up.

 

[mknauss]

Have you backwashed your sand filter in the past few weeks? Have you had to drain water due to rain in the past few weeks?
CYA is lost with both those processes. It also degraded about 3-5 ppm per month. The test itself is +/- 10 ppm. Always round up, so your current CYA is 60.

Yes, your SWCG is undersized. You can run it longer or add bleach each day during the summer to keep up.

Take care.

 

[Jimrahbe]

dze,

Your T-5 cell was designed for a 20K gallon pool. It puts out about .26 ppm of chlorine an hour, so in 16 hours it should generate about 4 ppm of FC.

Most pool use 2 to 4 ppm per day with not a lot of heavy use. This puts you at the upper end of the normal range, so most likely what you are seeing is normal.

If you want to make sure, you should run an Overnight Chlorine Loss Test (OCLT)... Here is how... Overnight Chlorine Loss Test The hardest part is getting your rear out of bed before sun up..

I have three pools in the DFW area and all of them loose some CYA each week.. I have to add CYA two or three times in the summer to maintain a 70 to 80 level.

Thanks for posting,

Jim R.

 

[kabutotx]

Your FC needs to be 7-9 for your CYA (rounded to 60). Add some liquid chlorine to get there. You can then run your SWG long enough to maintain that range or run it some and add liquid chlorine to help offset some run time.

 

[dzedaddy]

Curious... the Chlorine/CYA table in Pool School says min of 3, target 4. PoolMath says to target nearly twice that at 7-9. Which should I trust?

 

[mknauss]

Remember to compare SWCG values in each. You need to be sure you have the SWCG selected in PoolMath.

 

[dzedaddy]

Yes, exactly what I did.

 

[mknauss]

PoolMath shows the Target range for non-SWCG pools in the lower section based on your CYA.

There is not enough room on the PoolMath page to include all scenarios. Use the chlorine/CYA chart or just hold the higher FC range for your SWCG pool.

I target 10% of my CYA in my SWCG pool. It protects me from the ducks that like to visit and windstorms that blow lots of stuff in the pool.

Take care.

 

[dzedaddy]

8-10% of CYA levels seems like a good target, thanks!