New pool owner with a chlorine problem

Hello, my name is Aaron and I’m a new pool owner with a chlorine (or lack of chlorine) problem. This is my first pool and know very little about maintaining the water. I currently have someone doing it but would like to eventually take it over. I’m hoping to find some help here.

Pool info:
Approx. 17,000 gallons
Crushed quartz surface
Variable speed pump (currently running low speed for 6 hours and high speed for 3)
Cartridge filter
In-line chlorinator
Nature2 filter
Ozone generator
Operational beginning in April 2014
We don’t have any plants/trees depositing stuff into the pool but we do have a near-constant breeze that deposits fine dust/dirt (not sure if that contributes significantly to the problem or numbers that are posted below)

The problem (short version):
Ever since my pool was built in April there has been no measurable chlorine. Free chlorine and total available chlorine both measure 0ppm.

The problem (long version):
Every time my pool is tested, either by my pool guy or by the local pool supply store, there is no measurable chlorine. At first we thought it was a problem with the in-line chlorinator because the fill line was coming in from the bottom and the chlorine tabs weren’t dissolving but that has been fixed and the tabs are dissolving now. Before fixing the in-line chlorinator issue we noticed the presence of some water bugs which indicates the presence of algae but after fixing it we have not seen those bugs in the water at all. The water is clear and only sometimes has the feint smell of chlorine.

The pool guy last shocked the pool and added stabilizer on 6/25 and I had the water tested at the local pool supply store on 6/28 and still there was no chlorine reading. As far as the specific chemicals and amounts that the pool guy is putting in the pool, I don’t have that information (but plan to start requesting it). The numbers from the latest test on 6/28:

• Free available chlorine = 0ppm
• Total available chlorine = 0ppm
• Calcium hardness = 400ppm
• CYA = 25ppm
• Total Alkalinity = 60ppm
• pH = 8
• Phosphates = 300ppb

I have read about Chlorine Lock and there seems to be a lot of debate around that but, from what I gather, if I had that situation there would be a total chlorine reading > 0. The pool store recommended raising the Alkalinity and get it and the pH back into the ‘recommended’ levels and then raise the Free Available Chlorine. I haven’t bought anything yet because I want a second opinion on what the problem might be and how to resolve it.

Thank you,
Aaron

First off, you need your own test kit. We recommend the Taylor Technologies K-2006 and K-2006C test kit. And you need to do your own testing.

Secondly, your pH is high so you need to add some acid.
Your CYA/Stabilizer level is a bit low.

BUT, with 17,000 gallons and a CYA level under 30 I would immediately add 2 1/2 gallons of 8.25% liquid bleach. Wait 1 to 2 hours and then test your chlorine level. If it's 0 you are going to have to add ALOT of bleach to your pool, until you get a reading of 12ppm of Free Chlorine.

Given your low CYA, high pH and low FC, I would (if it were me) fill a floater with Tri-Chlor tablets. Trichlor adds chlorine, CYA (for every 10ppm of chlorine it add 6 ppm of CYA), and is very acid and will bring down your pH.
You can easily do the same by shocking with bleach, adding CYA powder, and using Muriatic Acid or Dry Acid to lower pH.

Thanks for the response Carl. Do I need to do the bleach AND the Tri-Chlor or will just doing the Tri-Chlor suffice?

Thanks again,
Aaron

Personally? I'd be pouring bleach or Liquid Chlorine (same as bleach, only stronger) in to get the FC up. The Tri-Chlor tabs take longer to release their chlorine. BUT DO NOT POUR THE BLEACH ON THE TRI-CHLOR. If there's a floater or you have tabs in the chlorinator, it's OK to pour the bleach into the return stream so it goes into the pool, but do NOT pour it into the skimmer!

As Carl said, you need to add chlorine now. Bleach will give you a predictable dose; trichlor won't since it has to dissolve, and you can't control the rate of dissolution directly.

Do this:

1. Order (as Carl told you) a K2006 => http://pool9.net/tk/

2. Go to Walmart and get 8 gallons of PLAIN 8% bleach, 10 pounds of baking soda (BAG, not box) and a cheapo OTO / phenol red kit

3. Go to Lowes, Home Depot and get a gallon of 31% muriatic acid and a set (or a box) of nitrile gloves (blue or purple, usually)

4. Test your pool with the OTO & phenol red. Confirm the zero chlorine and pH > 8.0

5. If chlorine < 1 ppm, add 2 gallons of plain bleach (about 10 ppm on your pool). Test chlorine after 15 minutes and again after 1 hour.

6. If pH > 7.8, read http://pool9.net/ma/ and then (READ FIRST) add approx 1/4 gallon of muriatic. Retest 1 hour later. Your pH needs to be below 7.8.

7. Retest pH & chlorine the following day. If there is no chlorine, turn off your ozonator, and add 2 more gallons of bleach. Test at 15 minutes, 1 hour, and 24 hours.

8. Report results.