When to Add Borates?

[tucsontico]

Been dialing in my water balance with a new Pentair IC40 SWG and think I've got it about right. I've got a 50 lb tub of boric acid and, according to the PoolCalc, I'll need about 48 lbs to go form 0 to 50ppm borate level.

My question is: Is there a preferred time to add borates? For example, should I add them in the evening, etc.?

Just thought of another question: when using an SWG, should I select "Chlorine Gas" in the PoolCalc to see the effect of adjusting run time/percentage on my SWG?

Test Results from this morning:

FC- 4.5
CC- 0.0
pH- 7.7
TA-120
CH-225
CYA- 60
Salt 3400
Temp- 76ºF

Thanks in advance!

 

[Melt In The Sun]

It shouldn't matter when you put it in. I think using chlorine gas would be correct.

 

[JasonLion]

The percentage setting doesn't have any clear relationship with the resulting FC level. You can use PoolMath along with the specification for your unit to find out how much bleach equivalent the SWG can produce, but not to find out what the resulting FC level will be. SWGs are specified in chlorine gas equivalent, so yes the chlorine gas setting.

 

[tucsontico]

Melt In The Sun (nice user name!) and JasonLion,

Thanks for the quick replies! Going to drop my TA a bit more before adding the boric acid. Trying to get it down into the 60-80 ppm recommended range. I've noticed TA comes down very slowly. Have added MA 3 times in the last week to drop the pH to 7.2 and letting the SWG aerate the water to raise it back up to 7.6-7.8. The TA has only dropped by about 10-15 in one week–looks like its gonna be awhile before I reach 80 ppm!

I understand there's no apparent relationship between percentage of SWG run time and a resulting FC level. As you mention, using PoolCalc, I'm able to estimate out how much chlorine gas SWG produces. That, in concert with twice-a-day testing, has allowed me to "dial in" my SWG run time and percentage to maintain FC at 5 ppm–so far .

 

[susa]

Going to drop my TA a bit more before adding the boric acid. Trying to get it down into the 60-80 ppm recommended range.

What works for me is simply to dial the Simpool to 7.4 and no matter how/when I add borate, the system adapts automatically and maintains the pH very close to 7.4-7.6 range