First TFT-100 test results

Jump to latest Follow Reply
cflannagan

cflannagan

Gold Supporter
Apr 2, 2011
149
Palm Harbor, Florida
Date: 4/8
Temperature during day: ~75 F

FC: 17
CC: 0
TC: 17
pH: 7.6
T/A: 130
CH: 360
CYA: 40?

Notes:
FC Test: Before doing my first TFT-100 test, took pool water sample to Pinch-A-Penny, which said my FC was 4.5 ppm, which was too low for CYA of 80 (two consecutive weeks of testing pool sample at store said CYA level was 80). I used pool calculator and it seems I needed about 1 gallon of liquid chlorine to get about 9 ppm FC, which I added to pool. The TFT-100 test results shown above was taken 24 hours after pouring 1 gallon of liquid chlorine into pool.
CYA test: I have to admit I have very low confidence in this test, because I was expecting a value somewhere between 60 to 80 based on Pinch-A-Penny results of our pool sample. I'm not sure if I'm doing this test correctly, but 40 was for sure when the black dot completely disappears without any traces.

According to pool calculator, CSI level is 0.12, which I think is too high, correct? What can I do to bring this CSI level down if it is a significant concern?

I am surprised the FC level is this high. Obviously either Pinch-a-Penny results was way off, or I miscalculated the amount of liquid chlorine I should be putting in pool to take it from 4.5 ppm to 9 ppm.

Any other comments about the test results?
 
Re: Firs TFT-100 test results

This is exactly why you keep seeing the phrase "we recommend that you get a quality test kit" on this site.
I'm not qualified to comment on the CSI, so I'll leave that to others, but nothing else looks bad. The FC should drop on its own, and then you can adjust the CYA as needed. I don't think I'd be in a rush to raise it.
 
Ok, thanks. Was just looking up T/A, and I think it's too high for my pool (I want 70-90, correct?). Looks like I need to add acid to pool, and then aerate water, which I understand my pool can do via waterfalling from spa to pool that it already does?

I will wait for advice on T/A and anything else. I agree FC definitely is high and I will not add any more chlorine for now till it falls down. I think I know what happened - with pool calculator I used the default "6%" value for bleach, and when I checked the container, it's actually 10.5% bleach, so yeah, that'd add more chlorine than I expected.
 
Just keep in mind that with an FC of 17 your pH is probably reading a little higher than it really is so if you adjust the pH down a point or two it'll affect your CSI. Having said that don't worry about CSI too much. A little one way or the other isn't a big deal. Just keep your chems in balance..
 
When using liquid chlorine or bleach we recommend a TA level of 70-90+, where the + means higher is frequently alright as long as your PH remains reasonably stable. As long as you are not having problems with PH constantly rising, there is no need to lower TA in your situation.

CSI is generally considered just fine between -0.3 and +0.3, and acceptable out to -0.6 to +0.6, so your CSI is just fine. Personally, I like CSI to be slightly negative, but there is no point in making an intentional adjustment to get there. Instead simply don't do anything to further raise TA, and it will probably drop on it's own over time.
 
Sweet, sounds like I'm in good shape. The pool water does look nice (it sparkles). Am happy with the new cartridge filter system that replaced our leaky DE filter system.

I have two goals in mind: to do something about all the plaster stains we have now (they are unsighty), and also to add borates (so-you-want-to-add-borates-to-your-pool-why-and-how-t4921.html).

We have numerous plaster stains, and I don't know what kind of stains they are (possibly I have multiple kinds). I'd like to start tackling the stains as soon as possible.
 
Let me reiterate a point that Dave mentioned earlier: High FC levels make the ph readings unreliable. Wait until your FC level is back to its normal level before you make any other adjustments so that you can get an accurate ph reading to work from.
 
Week 2 test results

Date: 4/15
Pool water temperature: 78

FC: 4.5
CC: 0
TC: 4.5
pH 7.7 (rough estimate)
T/A 120
CH 750 (!)
CYA 40 (got about 25 on first test, and 40 on re-test, which I think is more in line based on previous test numbers)

The only test I'm worried about is CH, with value of 750. I keep putting drops in, swirl about 3 times, color remains purple (more reddish than purplish), and after about 50th or so drop, I kind of gave up and put in 5 drops at a time before swirling, then add 5 more. eventually, it finally became faintly blue at 75th drop. I stopped there, because I fear this test might be invalid anyway. It's not possible to have CH go from 360 to 750 in a week, is it?

Any comments or tips in regards to the CH test? Should I retake it?
 

Enjoying this content?

Support TFP with a donation.

Give Support
Re-read the instructions, be sure you are following them, correct ml etc.

Save reagents with the CH test by:
For the Calcium Hardness test you can use a 10 mL sample, 10 drops of R-0010, 3 drops of R-0011L, and each drop of R-0012 then counts as (multiply by) 25 (instead of 10)ppm. This is handy if your hardness is somewhat high, plus it saves on reagents.

"It's not possible to have CH go from 360 to 750 in a week, is it?"
I wouldn't think so, something is fishy, don't worry for now, lets see what others say
 
Getting purple in the CH test is called a fading endpoint and can lead to significant test errors. I suggest that you do the test again, but this time add five drops of R-0012 before adding any R-0010 or R-0011L. Remember to count the initial five drops in the total. In extreme cases, a fading endpoint may occur even when adding five drops of R-0012 at the start. If that happens, mix pool water with an equal quantity of distilled water, test that, and then multiply the result by two.
 
zea3 said:
Have you added hardness increaser or calcium hypochlorite to your pool?
Click to expand...

According to history (looking thru print-outs from Pinch-A-Penny), before I got my TFT-100 kit, my wife was given "Calcium Hardness" (24 pounds) on March 1st. Nothing since. For tablets, we use trichlor (not cal-hypos).

According to pool store results (yeah, yeah, unreliable i know but this was before I got TFT-100), the numbers show 360. When I got TFT-100 and tested for CH, I believe the 360 value was confirmed.
 
JasonLion said:
Getting purple in the CH test is called a fading endpoint and can lead to significant test errors. I suggest that you do the test again, but this time add five drops of R-0012 before adding any R-0010 or R-0011L. Remember to count the initial five drops in the total. In extreme cases, a fading endpoint may occur even when adding five drops of R-0012 at the start. If that happens, mix pool water with an equal quantity of distilled water, test that, and then multiply the result by two.
Click to expand...

Shortly after I posted my 2nd week test results, I did see extended test instructions and came across "fading endpoint" that you mentioned. I added 5 drops of R-0012 first, then 20 drops of R-0010, and 5 of R-0011L. Again, the test didn't seem to go anywhere. Eventually I got very faintly blue water, but that kind of blue didn't seem as clear-cut as the end-result I look for from other tests in TFT-100 (hard to mistaken the results for other tests is what I mean).

If I get very faintly blue water (which really looks more clear than anything else), is that the result I am looking for? I think I might still be doing the test incorrectly.
 
If it turns purple you can miss the endpoint and keep going, eventually it will turn blue, but that could be well past the actual endpoint. If you use a speedstir, or otherwise mix more throughly than usual, you can usually avoid getting a fading endpoint.

The specific shade of blue doesn't matter as long as it stays the same blue even when you add another drop.
 
Ok, I probably should save on reagents since I have speedstir on way here anyway and re-test only for the CH test before doing the next weekly test. I've used up a lot of reagents today just for the CH test. Hopefully I'll be able to get better test results with speedstir when it arrives.

On a different note, I am thinking of adding borates to our pool this weekend. TA is a bit high, but pH seems to be at perfect level. Can I go for it, or is it critical to bring my TA down (and possibly CH as well, depending on my next CH test results?)
 
Got magnetic stirrer today!

Used alternative test methodology for the CH retest - using lesser reagents (10 ml pool water, 10 drops of R-0010, 3 of R-0011L, and then counting drops of R-0012 as 25 ppm CH each)

Still unsure if I'm doing test correctly (unlike other tests, even I am more confident doing CYA test) - because I don't know exactly how the test results should look like. When it started out, it was reddish. I added about 20 drops, and then at 21st or 22nd, the color finally became clearer - but "blue" was not how I would describe the water at first glimpse, but I do see blue tint if holding water against white background. Is that it, the end of test? I can go on adding more and it'll get bluer and bluer, but it becomes completely subjective after that point (becoming harder to tell if it got bluer with each drop)

So, if I stop at 22nd drop, that makes my CH 550. Still much higher than I expected. How on earth could my CH be 360ish for weeks, then go to 500+? I haven't had to fill my pool up a bit till yesterday. We haven't had much rain. Don't know what could be contributing to CH.

Getting a bit discouraged by all this CH chaos. Thinking of taking pool sample to pool store (without describing my situation) just to see what they say for the CH test.
 
Performed full test today with TFT-100.

Date: 4/22
Temp: 78

FC: 3.5
CC: 0
TC: 3.5
pH: 8.2 (give or take)
T/A 115
CH: 500? (On the 20th drop, using reduced reagent usage option, it turned very faint blue, but mostly clear, once again very subjective)
CYA: 40

The Pool Store says:

FC: 4.5
TC: 4.5
pH: 7.5
T/A: 115
CH: 310
CYA: 60

Once again, I have very low confidence in what my CH level really is. Don't know what to think honestly. When CH test reagents go bad, does CH results get higher, or lower? This is my only 3rd week of owning TFT-100 test kit and it is never left outside.. it's stored inside, in room temperature, in a dark place (my home office to be specific), and I doubt the reagents can go bad this fast, especially when I think I've been storing the kit properly.
 
You need to bring the PH down. You never want the PH above 8.0, and preferably not above 7.8.

On the CH test, you are looking for a color change to anything in the blue family, even a very faint blue, as long as it stays the same when you add another drop. As long as the color continues changing, you keep adding drops. The final drop, which does not change the color further does not get counted.
 

Enjoying this content?

Support TFP with a donation.

Give Support
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply