Leslie's CYA reading vs My reading using FAS-DPD Pool Water Test Kit

May 30, 2015
4
Houston, TX
So first of all I wanted to say thanks yo everyone on this site with the outstanding amount of information. Technically this would be my first post here, and I have been doing PLENTY of reading all the time. So kudos to the experts, I have been using the BBB method successfully and have achieved awesome results last year.

So here is my situation, when I first purchased my home last year it came with a 16,000 gallon oval 15x30 pool, with Pentair pump and 4x cartridge filter. I have two returns on opposite ends of the pool, one skimmer and main drain, vinyl liner (brand new). So when I took my sample water to Leslie's last year they told me my CYA was too low (around 20) I believe. So they recommended me to take some conditioner and add some to the pool that evening. So I did as they recommended with the amount. Later that week I noticed an extreme amount of algae growth, I cleaned the pool, brushed and vacuumed and took another sample to Leslie's. Now they told me that my CYA was over 100! When I was just there a week prior with the same sample.

Anyways I went through the entire summer add chlorine, cleaning, and always having an algae issue. I then decided to take things into my own hands and purchase the Taylor FAS-DPD K-2006 test kit. I started taking my own results and log my readings in my tally book. Looking at the CYA/FC chart here I noticed that my CYA was waaaaay above 100 range due to the use of tabs and the added conditioner to the water. I said to myself, before next summer I will drain the pool and follow the pool calculator guidelines. I diluted the water and retested for CYA and found that I was about at 180 CYA and was basically dumping unnecessary amounts of FC in the pool when I was still having algae problems.

So recently like a couple of weeks ago I drained my pool about 45% of the water and filled it back up. I checked the CYA levels again and outside I was getting 100, inside the house I was getting 80?!. Last night I drained it again and brought it down to about leaving almost 3 feet of water in. I filled the pool again, to about 50% and still my CYA is about 90 to 100, ***..... :|. I took my sample to Leslie's and they gave me a reading of 60! Am I doing this wrong? Do I have to do the test in a dark location or in a sunny area with plenty of light? I did buy my CYA regent off of amazon in a 32 ounce cause I ran out of the one that came with the kit last year :D.

So Should I go with Leslie's readings or mine? I'm really confused. I feel like I am doing something wrong with my CYA testing. Any jedi advice would be greatly appreciated.
 
Welcome to TFP Tacos!

Not to be short, but to make it easy, it's best to learn and trust your own readings. Mixing results with your own and the pool stores will be less than helpful, and almost always lead to headaches. Get a feel for the Cya test, and you'll be fine. This is one where most P Stores have poorest readings. Test outside in bright indirect light (sun at your back) and you'll get a good reading. Just takes a little practice.
 
Thanks for the response!

I did the test twice to make sure I wasn't going crazy but I think I will stick with my own results like you said, I did it twice and it was around 90 with 50% of the pool filled. So I guess my next question is should I continue to fill the pool up to 100% and redo the CYA test or should I drain again until I get a somewhat decent reading? So if my reading is at 90 now with about 50% full, and according to the pool calculator If I do some backward calculation it says to get to 40 CYA I need to replace 56% of my water with a reading of 90. Would this be accurate?

15x30 oval @5.5 deep, IG pool calculates this to about 16.5k gal
 
For me, the CYA test was the hardest to master. As Patrick says.. outside, sun at your back, tube about waist high. The key for me is not to '"Stare" at the tube.. look away, glance at the tube looking for the dot, look away, glance at the tube.. etc. Keep in mind you can pour the test sample back into the mixing bottle and keep repeating the test over and over until you can get consistent results.

Another thing you can do is buy a bottle of standard reference solution which reads 50% and adjust your testing methods until you can consistently get a reading of 50%.

Jim R.
 
If you are only 50% full, filling the pool should cut your CYA around half to ~45.
:goodpost:


Just to give you the example of my pool - When I took it over the pool stores (I went to two to verify) told me my CYA was around 90. With my test kit and using diluted methods which skew the results I found I was way north of 200, I just say 250. Like you it took numerous drain and refills, mine even more because of my high water table I couldn't take it down far without fear of floating the pool.

Trust your numbers.
 
You are on the right track with your testing. Trust YOURS! I also like the glance method........if you stare long enough you WILL see the dot LOL

Keep filling your pool. I have a feeling Marian's guess will be about right when you get your water up to the skimmer and mixed up with the pump.

Let us know what you find this morning!

Kim
 
The trick I learned from someone here is to do the CYA test as normal but pour everything in to a 25ml tester then you can pour as many times as you like going back and forth.. after 20 times you get the hang of it and come up with the same CYA number almost every time... :)
 
Just glancing for the dot is the way to go. I put solution in the tube to the 100 mark then glance. If I see any of the dot, I add solution to the next line and glance again. I repeat the procedure until the dot is gone and use that value. Remember, glance, don't stare.
 

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Yes, I like the sound of that testing method too! Gonna test it out to see how it works for me.

I bought the testing reagent that is a known 50ppm and it helped me confirm what i *thought* I was seeing.
It didn't cost too much but it came in quite a large bottle. I wonder if TFTestkits would consider bottling it up in smaller sizes (I mean really, once you see 50 and get comfortable, how much more do you really need???) and sell it at lower cost as an option when buying a test kit for the first time. I need to suggest that to TPTB, huh?
 
As a mater of fact I am originally from New Orleans, I moved to TX about three years ago and been using this name for a lot of the forums and even my gamer tags :p, but all my buddies call me tacos :D

*Update* I tested the CYA following y'all advice and I got a whopping 65! So I think I'll fill the pool up and shout be close to 30(ish) (crossing my fingers). I did that method of sun in your back, and the testing tube by your waist and just gazing it little by little. I did it three times and it was the same :D

Which testing regent has the 50ppm? I'm curious now....

Oh goodness. I just keyed-in on your user name. Spoken like a true Houston. That's hilarious.
 
Which testing regent has the 50ppm? I'm curious now....

TFTestkits.net

This is a standard solution you use in place of your own pool water, and then continue with your regular CYA test. Because it has a known value of 50ppm it lets you gt comfortable seeing (or not seeing, a the case may be!) how the dot in the tube should look.
 
The 50 solution was VERY helpful with one member. She could not see her CYA test clearly. She even got the 50 solution and still could not see it as being 50.

When I did some deep questioning of her to make sure she was doing it right she did the test while videoing it so we could watch her do it. WELLLLLLL guess what........she could see it through the view finder of her camera! We are still not sure why that helped but we were just happy she could see it.

Kim
 
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