Fas-dpd

[icyjay]

I shocked my 15000 gallon plaster pool last night with 2 lbs of shock. I ran a FAS-DPD test just now and it required 98 drops of reagent to get it to turn clear. Measured at 25ml I multiplied that by 0.2 and got 19.6. Does that sound about right? I don't recall having to use 98 drops in the past. My power isn't really powered anymore its like crystals that I break up and let dissolve when I mix it up with the water.

Also with a CYA of 60 what FC level should I try and maintain with 12.5% bleach in order to keep up a good FC level?

 

[jblizzle]

Why 2 pounds? Was that what PoolMath suggested you add to reach a desired target FC level? What was that target FC level?

What is the powder? Are you sure your CH or CYA can handle the side effects from it?

Use 10ml of water so each drop is 0.5ppm.

Follow the recommended levels in the [FC/CYA][/FC/CYA] chart.

 

[icyjay]

pool math said to get shock level to 16, it appears Im over that at 19. The shock I used was Pool Essentials. I just ran another FAS test using the 10ml sample and my FC is 16. So Im right at my shock level per pool math but not at the FC/CYA Chart which shows 24. Do I need to increase my FC to 24 or just maintain my FC at 7-9 per the chart?

 

[jblizzle]

PoolMath and the Chart should have the same shock level for a given CYA.

You have PoolMath CYA set to 40ppm.

 

[elwood58]

+1 on using 10 ml sample, especially at high FC levels.

We recommend a SLAM, which is a process, versus shock which is a pool additive fraught with many risks. Follow the procedure documented here at TFP, using just bleach. Depending on your reasons for shocking, I will guess wildly at 10-12 gallons to get the job done.

 

[icyjay]

I will look to SLAM this week, being that I haven't done that before while your maintaining your levels do you need to backwash or clean the filters or wait till the slam is completed before doing that?

 

[jblizzle]

You should always clean your filters when the pressure rises 20-25% over the clean pressure.