Chemicals Required to Open Pool

Hey guys, This is only my second post here. I had a gunite pool installed last year. I am getting ready to start it up for the summer. It's been uncovered all winter and I've been adding chlorine tablets as needed and shocking it here and there. My pool also has an ozinator on it and I am aware of how most of you feel about it. I am however undecided and I have a few more months to decide if it's useless or not before I cannot get my money back on it. I have purchased a K2006 kit and just tested chlorine, PH, alkalinity and calcium. Here are my test results, can someone help me decipher them?

Chrloine:
added .25 of water, 2 scoops of R-870 and the water turned pink.
7 drops of R-871 were required to bring the water back to clear
added 5 drops of R-0003 and the water remained clear.
No further testing performed as the instructions indicated the remaining steps should be performed on pink water.

Ph;
5 drops of R-0004 turned the water pink matching the 7.8 window.

Alkalinity;
added R-0007 per instructions and water remained clear
added R-0008 per instructions and water turned green
7 drops of R-009 were required to turn the water pink

Calcium;
added 20 drops of R-0010 per instructions
added 5 drops r-0011 per instructions which turned the water a very light pink
23 drops of R-0012 were required to turn the water blue.

You need to test your Cyanuric Acid (CYA) level. Also, if you could post some details about your pool (volume, pump and chemical equipment, etc) that would help too. CYA is what determines where your chlorine level should be for properly sanitized water.

If I'm reading your test methods accurately, then here are your numbers -

FC = 1.4ppm (I assuming you used the standard 25mL level but that FC is awfully low)
CC = 0 (that's good)
pH = 7.8
TA = 70ppm (not bad, about right)
CH = 230ppm (normal)

Without the CYA number, there's no advice on what your FC level ought to be.

I just did a CYA test. The black dot disappeared at about the halfway mark between 30-40 so I'd say it's 35.

The pool is I think around 12,000 gallons but I am horrible at remembering numbers. It's a shallow gunite pool with a pretty big tanning ledge. I don't have any kind of chemical equipment or anything. My filter is a cartridge filter and I have an ozonator. I've read that ozone depletes free chlorine and every FC reading I've ever done was pretty low.

I should have mentioned that I do have the 3.5" tablets in my pump.

Quote:

---

Originally Posted by jmarcum

I should have mentioned that I do have the 3.5" tablets in my pump.

---

As in 3" stabilized chlorine tablets?

I forgot to take note of the fact that you have an ozonator hooked up. I'll stay away from the "politics" of ozone generators and stick to the facts that the added ozone explains why your FC is low, your CC's are 0 and your water is clear. O3 is good at oxidizing the combine chloramines but it's efficacy as a disinfectant in a residential pool is debatable (spas and hot tubs with ozone are a completely different story).

That said, I'm not entirely sure how to help you. Normally in a pool like yours, you'd want to target a CYA level of 30-50ppm and an FC in the 3-7ppm range. At 35ppm CYA your minimum FC should be no lower 2.5ppm. I suspect the ozone system is allowing you to maintain a lower FC and not have an algae bloom but you are walking a fine line between clean and green.

Also, putting chlorine tablets in the pump is not really a good idea. They should be used in a floater. Chlorine tablets are basically 99% trichloroisocyanuric acid (thrichlor) with the operative word there being ACID. Tablets are very acidic and can lower the pH of water quite a bit. So, when your pump isn't running, the tablet is slowly dissolving and the water inside the pump is becoming very acidic. That can do damage to the pump over prolonged periods of time. As well, trichlor pucks add CYA to your water so that, over extended periods of use, the CYA level of your pool can rise to high values causing the FC to become less effective (typically CYA > 100ppm makes it hard to stay sanitized).

Perhaps some others might chime in soon. I don't have a lot of experience with ozone in pools and the values you may want to target could be quite a bit different from chlorine-only pools.

I probably said that wrong, the tablets are actually in the pump, the are in a tube beside the pump. On that there's an adjustment which I usually keep around 2-3 which is about 50%. I've actually lowered it before to try to make the water cloudy and it seems like nothing I do will make the water in this pool cloudy. My pool builder said as long as the water is crystal clear don't worry about anything because the ozonator is doing its job. I have a hard time believing that and that it could really be this simple to maintain a pool so I am constantly worrying about when I'll wake up to a green pond in my back yard. :-)

I turned the adjustment by the tablets up to 5 (the max) yesterday just to see if the FC will come up or not. I'll take a sample today and post my results. But as I am interpreting your last reply maybe I should just stop stressing and enjoy the pool?

If I needed to raise the CYA at some point what is best used to do that?

This was taken within an hour of the pump shutting off after running over night. FC 1.8 and CC .6 water couldn't be more clear

Since you're a puck user, I have a hard time believing your CYA is as low as you say it is. Sometimes the CYA test can be tricky. One thing you could do as a sanity check is to perform a diluted CYA test - take a sample of pool water and dilute with distilled water in a 1:1 ratio (50% dilution). Then perform the CYA test and multiply the results by 2.

So you turned up you chlorinator and now your CCs are up to 0.6ppm? That's a bit troubling to me. You could be on the verge of an algae bloom. I find it very disturbing when pool builders say "if the water is clear then it's fine." That's a hugely misleading and false statement. Clarity is not an indication of sanitary water.

As for CYA, I prefer to use solid stabilizer (100% CYA) sometimes called conditioner, and then I put it in a nylon skimmer sock and let it sit in front of a pool return until it dissolves. It can take up to a week for the added CYA to register on the CYA test so it's best to raise CYA in small increments. Since you use picks for chlorination, your CYA should naturally rise in its own unless you do lots of major water exchanges.

Retest the CYA using the dilution method and post results.