I am new to this and have only done about 10 CYA tests in my life starting about 2 weeks ago. However I am getting some huge swings in the level, I started out low, added CYA as per poolmath shot up to 40. I was happy and was going to use trichlor and when it got to 60 (I was hoping end of season) I would do a water exchange to lower for next season, a week later I am reading 50, so figured better stop trichlor that is bringing up way to fast, week has gone by I test yesterday I am reading 20. Any Ideas on what I am doing wrong? By the way the pool has not been used very much and I usually test CH & CC 2 x/day early AM & 6-7 in PM. overnight loss usually < .5 on FC, daytime loss about 2, this has really not fluctuated over the past week and a half since I came off slam, slam was only a few days because with knowledge from here and using pool store # till I got the test kit. I was dialed in close and my pool store testing was pretty accurate except for CYA could not read, they said it was because TA too low but TA was 70 so while it can be raised a little I did not think it a major problem.
Getting wide fluctuations in CYA level
- Thread starter Pool Amateur
- Start date
- Jun 22, 2014
- 47,759
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
A note from a previous discussion: "Proper lighting is important for the CYA test. You want to test on a sunny day but keep the view tube in the shade. Taylor recommends standing in the sun with your back to the sun and the view tube in the shade of your body. Other than that, try it a number of times with a sample that you use over and over again, it should be good for at least five minutes, and see if you can get repeatable results. The CYA measurement is never exact. If you get results that are all within 10 of each other then you are doing well."
Hope this helps give you ideas and reassurance. It can seem a bit finicky, but you'll get it. Good luck!
Hope this helps give you ideas and reassurance. It can seem a bit finicky, but you'll get it. Good luck!
Lighting is the key. Always try to test on days with similar lighting, preferably a nice sunny day.
I always pour back and forth between the mixing bottle and the tube multiple times to get a good reliable reading each time I test.
Thanks, the lighting may be the key, I will try as will as get a reference bottle with known CYA.
More detailed instructions are also available here: Extended Test Kit Directions. Post # 8 deals with the CYA test.