any problem keeping fc higher?

[roth79]

I live in Florida and have a refinished wet edge about 2 years ago, my FC is about 15 and I am wondering if this throws off the rest of the readings from my TFT100 weekly testing? I am a little nervous letting it drop as I do travel and only get to the testing and dosing once a week. The temp is 60 degrees today and I just added MA and BS.

Thanks in advance,

roth79

 

[woodyp]

If your SWG is currently "producing" FC......there's no reason to keep your FC that high. Other than that............an FC of 10 or better will cause PH to read falsely high.

 

[Jimrahbe]

roth,

You knew it was coming, so here it is.....

With a SWCG pool once a week testing is fine. I like to keep my FC at about 7 or 8 ppm.

As woody asked.. is your SWCG producing chlorine? We ask because some of us live in places where it is cold enough to shut the SWCG off...

I'm a little puzzled why you are adding MA, which lowers your TA, and also adding BS, which is increasing your TA???

Thanks for posting,

Jim R.

 

[simonoaks]

Where in FL are you, the cold North or warm South ?

 

[roth79]

I am in West central florida by Redington shores/ Seminole area, the water temp today is 64, the readings today are as follows.

FC 12
PH 8.0
TA 90
CH 410
CYA 80
SALT 3200
Borax 50

So the reason I asked is using the pool calc today I would of added 1 quart 2 cupos and 7oz of MA, so the original question is the higher FC reading throw off my PH test? I do know the SWG is working as I just lowered the timer and the settings last weekend and it did drop from last weeks higher FC reading.

Thanks again,

Roth

 

[Patrick_B]

It likely is throwing off the pH, or enough that you should let it get below 10 now and retest. I wouldnt make any big acid additons until I knew for sure.

 

[Jimrahbe]

Roth,

The general rule is the any FC over 10 will have an effect on pH testing accuracy. I am not sure how fine a line this is??? Is 10 ok but 11 is not? Does the accuracy error increase as the FC gets higher and higher? Maybe we can get some feedback from our chemically minded members...

Have you ever tried to lower your TA to 60 or 70? I find that my pool's pH level stays at 7.8 for several weeks if I keep my TA at about 70.

See this link about reducing TA... https://www.troublefreepool.com/content/129-how-to-lower-lowering-total-alkalinity

Thanks,

Jim R.

 

[pabeader]

According to the extended testing article the effect goes up as the FC goes up.

 

[Caco]

Summarised from a discussion between Jasonlion and Chemgeek

The ph is accurate when FC is 0-10, the ph will read increasingly high from FC 10-18. Above FC 18 the ph test is completely unreliable

 

[roth79]

Todays numbers:

PH 8.2+
FC 4
TA 100
CH 410
CYA 70
Borax 50
Temp 68

Pool math tells me to add 2 quarts 3 cups MA but? not sure. Going to raise fc a little by uping to 60 percent for the SWG.
The pool is not enclosed and we have oaks near so the pollen is bad right now.

Thanks,

R

 

[pooldv]

Yes,lower ph to 7.6, it is important to keep PH between 7.2 and 7.8 at all times.

Here's why, Pool School - Calcium Scaling