Need some help with Taylor readings

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Need some help with Taylor readings

Postby Guest » Sun 10 Aug, 2008 07:17

I'm having a little trouble reading the CYA levels on a Taylor test kit. I understand you pour it into the cylinder until the black dot disappears. Am I reading the inside numbers of the tube to get the ppm reading?

The only reason I'm wondering is because

1.) leslies says it is at 40ppm but the Taylor says 90ppm

2.) Just using normal test strips (getting rid of them) all other readings are spot on except the stabilizer which reads very low to none.

Conflicting results to say the least. These tests were done after adding 40lb of alk and 20lbs of PH. Also will an abundance of one chemical confuse this reading?

How do you figure out the % of available chlorine?

I had an outbreak and the water turned green. Turns out my ph and TA were very low so I added them. After a few days of shock the water is now very cloudy. It sounds normal after an outbreak like that, and will probably take a week to get the water clear again. Should I back off of the chlorine to get it back to nomal level by turning off the chlorinator? The chlorine is off the chart on the taylor test kit.

chem geek
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Re: Need some help with Taylor readings

Postby chem geek » Sun 10 Aug, 2008 12:05

The instructions for the Taylor CYA test are at the end of this link. Yes, you look at the BACK of the tube with the inverted logarithmic scale as shown here and you add more of the mixed solution (the one where you mix half pool water with half reagent and mix for 30 seconds) until the black dot disappears as shown here.

I would generally trust your test rather than the pool store's and the test strip since the latter is often not correct (depending on brand, but most are not very good for this test). However, if you have algae in the pool or the pool is otherwise cloudy, then that can lead to a falsely high reading, though not usually by very much (perhaps 20 ppm) unless the water is VERY cloudy. You can just add pool water to the tube to see if it looks cloudy or has the black dot get harder to see even when filled up to the top.

High chlorine levels should not interfere with the CYA test, though it will interfere with the pH test (sometimes giving a falsely higher than actual reading) and with the TA test (going from blue to yellow instead of green to red).

You can use The Pool Calculator to figure out dosing. I'm not sure why you want to figure out the % Available Chlorine (which is by weight).

Yes, cloudy water after shocking green algae is usual and takes up to a week to clear (unless you use a flocculant which sometimes works well -- OMNI Liquid Floc Plus -- but then need to vacuum to waste what settles to the bottom). Brush the walls, run the filter 24/7, and clean/backwash the filter (possibly multiple times depending on how much there is to clear). Keep the chlorine at shock level 1) until the water becomes crystal clear,
2) you measure minimal (< 1 ppm) loss in Free Chlorine (FC) overnight and 3) you measure minimal (<= 0.5 ppm) Combined Chlorine (CC).

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