Trichlor and no CYA

[GreatCanadian]

Starting a friend on the BBB method. His pool is in its second season and he has used only Trichlor for sanitizing. Tested his water today:

CYA = 0
CL = 5
CC = 0
TA = 30
CH = 50
PH = 6.8

What is it with the CYA. Ran the test with 3 different water samples. Started to wonder about bad reagent so I just tested my own pool water and CYA measures 70 as I would expect. His water is clear. Any explanation why CYA reads zero? Thanks.

 

[UnderWaterVanya]

Had chlorine fallen to zero lately?

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[GreatCanadian]

Don't know but I'm betting yes if CYA is actually zero.

 

[duraleigh]

Before we jump into CYA eating bacteria (which it very likely isn't), what did he expect his CYA to be?

To go back and try to reconstruct what he has and hasn't done to his pool is almost impossible. All kinds of possibilities but are all nothing more than guesswork unless he tells you everything he did and didn't do.

I would simply bring the CYA up to where it need to be and get started clearing his pool.

 

[GreatCanadian]

His pool is clear. And he knows nothing about CYA or the CYA/Chlorine relationship. His switch to BBB came from a suggestion from me. What I can tell you for fact is this:
He has used trichlor for the past 2 seasons.
He recently put pH reducer in his pool (too much according to my tests)
And on a couple of occasions, he has noticed a LITTLE bit of algae around his ladder. He is gone to the store now to get CYA, borax, Muriatic acid, bleach, and baking soda.

I guess I just won't wonder what happened to the CYA, and just be thankful that it isn't sky high!! I'll just balance his pool as it should be, and watch it for a few days. He'll have to get a good test kit, but in the meantime I will test for him.

 

[chiefwej]

Yep, most converting to BBB have sky high CYA to deal with. Be glad that isn't the case. It's a lot easier to add it than get rid of it

 

[GreatCanadian]

Here is a pic I took of the label. It's poor quality, but hopefully you can read it: