Help with readings please

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T

Thesil

0
Jun 24, 2013
123
Northern NJ
Ok just used the tf-100 to test my water. My FC =0.25 and my CC=2.5 for aTC of 2.75. My CYA has been at least 100. I stopped using trichlor. The pool calculator says I need over 500 oz of bleach is that right? I'm sure my readings Re correct. I thought if CYA was so high that the chlorine would not be that low. I'm new to this please advise
Thanks
 
What was your FC sample size? 10 ml or 25ml (almost full)

How many drops did you add to make the pink go away
I then assume you added the 5 drops (pink again) and then how many more drops to make the pink go clear on the second test? 2.5 sounds like 5 R-0871 drops.

I ask as 0.25 FC is not a value you can measure with this kit.
 
What size water sample are you using?

The instructions say to use 10ml of pool water, resulting in FC results in increments of .5.


The instructions do have a printing error: after it says "Multiply the number of drops you added x 0.5" it incorrectly states: "(i.e. 14 drops x .05 = 7ppm)".

This error in the instructions has confused others as well.....

The instruction card should be corrected, or there should be a little note included that clarifies the mistake, IMO.
 
Yes. We typically report FC = 2 and CC = 0.

Since the FC is way too low for your high CYA, you could have something growing in the water.

Try the CYA test again with a 50/50 mix of pool and tap water to start, add the reagent, then double the reading. Then you will want to replace water to get the CYA into the recommended range. Followed by at least the OCLT to confirm if there is something in the water and quite possibly the need for the SLAM process.

EDIT: and 500 oz will raise the FC in your pool by about 8.8ppm. ... depends what the Now and Target levels you entered into the calculator as to whether that was the desired result.
 
Yes, your reading are

FC 2.0
CC 0.0

for a 10 ML sample with a scoop of powder, 4 drops of R-0871 to turn clear and then 5 drops of R-003 and it stayed clear.

OK, so yo have 2FC, this is WAY too low for a CYA of 100+.

OK...on to the next step:
What does the water look like?
Where are you located?
How much swim season do you have left this year?
Is clean fill water easy and inexpensive?
 

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OK ....... according to the chart: pool-school/chlorine_cya_chart_shock

if your CYA were 100ppm, you need to maintain the FC above 7ppm at all times to prevent algae from starting. But, you said the CYA may be higher, so you need to do the dilluted CYA test to find out how high the FC should be.

I would certainly add at least 4 of the 121oz 8.25% bleach bottles immediately to get the FC up some and then verify the CYA.

You are going to have to try to just limp through the next few weeks on hope before your drain for closing. And learn for next year to not use so much trichlor.

@GP ... I don't think it works that way. There is a discussion about this somewhere.

@ Thesil, well with a CYA of 180ppm, the minimum FC is 14ppm according to the calculator ... that is going to be tough. And remember the pH test is invalid when FC > 10ppm
 
You really need to replace about 75% of the water. But no sense doing that before the spring. Maybe you will get "lucky" and have the CYA reduce/disappear over the winter.
 
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