High FC Comparator Block?

RedHook

Member
Jan 31, 2010
13
Beautiful Downtown Burbank
I'm keeping my FC around 10 this summer due to CYA of 90. I already drained once to bring it down from 200+, so I'll wait to do it again. Is there a place where I can buy a comparator block that measures FC levels that high? I already have the TF-100 kit, but I'd rather not use the FAS/DPD test every day. I know I could dilute with tap water, but honestly, I'm looking to be a little bit lazier than that!
 

coloeb

Well-known member
Mar 13, 2009
226
Nope, you will need to use your tf-100 kit, or use dilution method. Also with a fc of 10 your ph readings wont be accurate.
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,880
Silver Spring, MD
Many people use the simpler OTO chlorine test daily just as a simple chlorine/no chlorine check to make sure nothing is going wildly wrong, and then only do the full FAS-DPD chlorine test once a week to see if they need to adjust the amount of chlorine they are adding each day.
 

RedHook

Member
Jan 31, 2010
13
Beautiful Downtown Burbank
I passed by the paint counter at Lowes and pulled some yellow chips to bring home, but it's pretty hard to compare. I'm getting familiar with the shade of yellow that 10ppm gives me in the OTO, and I'm also getting a handle on how much bleach I need every day, so thanks for the reassurance, Jason!

Coloeb, I hadn't heard that before. How much variance should I expect?
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,880
Silver Spring, MD
If FC is right at 10, the PH reading will be quite close, just a tiny bit higher than actual. As FC goes up from there, the PH test continues to be higher than actual by more and more, until a little above an FC of 20 it goes totally haywire.
 

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