Numbers review please...

[orion6192]

Okay - so completely flushed tub with Ahh-Some many times (read other threads I have posted) and I balanced the water.

my numbers are:

FC 5
PH 7.8
TA 80
CH 190
CYA 8.5 calculated target will be 35
Borates 50 (GentleSpa)

My PH was right at 7.4-7.6 until I added the Gentle Spa and it spiked to 8.0-8.2 and raise the TA 30 - which is common. Then it dropped a little to 7.8. I added the borates when I had the PH at 7.6 which would have given me a CSI of 0 when my CYA gets to 35.

My question is if I add acid, I'll drop my TA. Is it better to be slightly neg or slightly pos?

I add 100 gallons of soft water when I did this fill - usually my CH is 320+

Any input on what my target numbers should be?

Thanks All -

Scott

 

[pooldv]

You want CSI to be negative, anywhere between -0.6 and 0 is fine. TA target should be 50. The rest of your numbers are fine. Nice work!

 

[orion6192]

A TA of 50 would put me at -.28 @ 7.6 and -.15 @ 7.8. I know we use 50 as a guideline but is -.28 too low?

 

[pooldv]

No, it is fine. Anything -0.6 to 0 is totally fine. Aggressive water is only a potential issue with plaster and grout. As long as your pH stays at 7.2 or higher you are good to go from a corrosion standpoint.

 

[orion6192]

Ok - so my final numbers are as follows:

i stepped it down to first a TA of 60 for a few days and let the numbers settle. Then yesterday I dialed a little more and here's my final result:

TA 50-55
PH 7.6
CH 190
FC 5
CYA 14.4 calculate - shooting for 35
Borates 50
Temp 100

This would put my current CSI at -.2 and my future CSI when I get to 35 to -.29.

I have never gone this negative - I've always stayed at 0 or slightly positive. I guess negative would help with corrosion?

My question is - do you still shock you tub to once a week @ 40% of your CSI number? Even if the tub is used or not used?

Appreciate the feedback!

Thanks all -

Scott

 

[pooldv]

Negative CSI prevents scale build up in the tub. More here, Pool School - Calcium Scaling

I have never shocked my tub. Keeping FC above minimum, [FC/CYA][/FC/CYA], will eliminate the need to shock. After heavy use just be sure to retest FC a few hours later to make sure it is holding. If it is too low then add some more.