How do I know how much stabilizer to add?

[jboss]

How do I know how much stabilizer to add?

I have a 16000 gallon SW IG gunite pool ... the previous owner neglected it, but had a pool guy taking care of it while it was on the market, so the plaster looks bad, but the water was great. ...for the first four months it was perfect, and almost no maintenance (central florida OCT - FEB - so water temp was low 70s) ... then I decided I was pushing my luck so I went to the professionals ... a pool store, for the free water test ... I did it weekly for about two months, and after spending a few hundred on chemicals and doing exactly what they said I had a foamy, cloudy mess that smelled funny and my chlorine was almost non-existent ... it wasn't green, but it was cloudy enough I couldn't even see the drain at the bottom ... when they told me I should go ahead and buy a new SWG I walked out. That was the last time I was there.

I fretted for about a day, googled things for a day, then called the SWG manufacturer and gave him my numbers ... he said the SWG was fine, but given my location and the amount of rain we had last spring I should check phosphates. Phosphates were high so I replaced about 2000 gallons, and I added about 8 gallons of unstabilized bleach over the next two weeks, and I bought a Taylor K-2006 FAS-DPD test kit (abt $60 on Amazon or Ebay) ... and two weeks later it was once again crystal clear.

My latest numbers are as follows:
FC = 7
CC = 0
pH = 7.6
TA = 99
CH = 260
CyA = 0 (given my FC reading I'm not sure if I should be worried about this ... but anything I do to extend the life of my SWG would be good).

... can anyone tell me the best/cheapest stabilizer to add, and how to calculate dosage? (that is the one piece of info I can't find in the Taylor Test Kit - Pool Water Chemistry Bible.

 

[pwrstrk]

Welcome to TFP !!

You can use the pool calc to figure out your CYA dosage calc.html.
Use granular stabilizer , it's cheaper. You can get it Walmart or pool store. You'll want your CYA level to be 70-80 ppm for your SWG.
Here is some other good reading pool-school/salt_water_chlorine_generators
pool-school/pool_water_chemistry
pool-school/chlorine_cya_chart_shock
Lots of other good reading in pool school.

 

[linen]

Welcome to tfp, jboss

Just curious how did you come up with a value of 99 using the K-2006? Each drop is either 10 ppm (if using the 25 ml sample) or 25 ppm (if using the 10 ml sample).

Per the link that pwrstrk pointed out to you, our recommended cya level for a swg pool is 70-80 ppm. This will reduce the on time of your swg, and in-turn increase calender life.

Phosphate levels do not matter in a properly chlorinated pool.