Alternative chlorine test

dickeystorm · Apr 23, 2011

Help, I messed up. I opened the pool this weekend and it was pretty much a disaster, nasty and green and 2 foot low. My dilema is I've run out of the R-0871 reagent for testing FC levels. I reordered but it will be a few days until it gets here. I have an OTO kit but it only goes to 3 and I am trying to shock the pool. My last reading was 14 FC .5 CC so the 3 limit doesn't help. Is there a trick I can use to at least get a ball park to know if I'm in the shock level using the oto kit?
IG Plaster
25000 gal
72 F
Added 910 oz (5 jugs) 6% after 14 reading
CYA ~120
TA 220
CH 400
pH 7.5
water light green and a bit cloudy but improving

Thanks,

Richard320 · Apr 23, 2011

Two ways to do this, and neither one is very good.

1) Dilute your sample 4:1 or 5:1 with distilled water then see what it reads and multiply by the appropriate factor. If you're looking for 15, I'd guess you could be anywhere between 5 and 25.

2) Use the OTO. From my experience just fooling around, blinding yellow is about 10. School bus yellow is about 12-13. Hunter orange is around 18.

You can always overshoot. As I recall, up around 25 it starts to look pumpkin orange.

Or, just consider the bleach you poured in lost and wait for the R-0871 to arrive. Realistically, the lost bleach probably cost less than what you'll waste guessing at FC levels.

Isaac-1 · Apr 23, 2011

If your CYA is 120, you should consider some water replacement before trying to clear this as even with a working test it would likely take A LOT of bleach.

Ike.

dickeystorm · Apr 23, 2011

Thanks for the reply's. I diluted 5:1 and got a bright yellow that is equal to the top level on the oto (5, thought it was 3) or better. I'm going to let it ride for the night and decide in the morning whether to fight it or do the water replacement. I fought the high cya all last season, you'd think I'd remember hehe.

JamesW · Apr 24, 2011

Your high CSI is probably contributing to your cloudiness. You should lower your pH to about 7.2 and begin working on getting the TA down.

JasonLion · Apr 24, 2011

You don't want to try and adjust PH while the pool is at shock level, the PH test won't work correctly. Leave anything to do with CSI or PH until shocking is complete.

Bama Rambler · Apr 24, 2011

As Jason said, don't adjust the pH. At least until your FC gets back to 10 or below. My recommendation is not to even test the pH while shocking because it just confuses the issue and it's not going to be accurate at shock levels. Just leave the pH in the pool calc that you got before you started shocking.

If you keep the levels between the recommended ranges you don't have to worry about the CSI. It won't get far enough one way or the other to be an issue except in very special circumstances.