Recently I posted a possible reason for changes in the stabilizer levels in pools that are turbid. Here is my post:
Waterbear then said in reply:Another possible reason for the differences in the readings is due to the "algae" eating the stabilizer. Typical scenario: Pool owner finds a white turbid pool, checks CYA to find shock level. CYA measures 40 ppm. Shocks the pool, meanwhile the bugs are munching away on the CYA. Poll finally cleans up, pool owner checks CYA again. Finds the new value at 20 ppm. Probably 15 ppm loss was due to the bugs
Well Mr. Waterbear I beg to differ with you. I have had the exact scenario I described happen to me. And my pool was NEVER stagnant. I agree that the organism(s) in question are probably not algae. That is why I place that word in quotes. And if it happened in my pool it can happen in another.Algae does NOT eat CYA. CYA is consumed by anerobic (oxygen hating) denitrifying bacteria that are commonly found in soil. For this to work the pool MUST be stagnant because any circulation would increase the oxygen and the bacteria would die! This is why CYA sometimes disappears in a closed pool during the winter. The water is NOT circulating and is stagnant so the aerobic bacteria can grow. Also, this is a slow process and does not happen in the matter of just a week or two.
The effect you are talking about above is from the clouding of the water from the algae and it's interference with the CYA test!
I rest my case!