Chemicals Required to Open Pool

[SunnyOptimism]

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.

[jmarcum]

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?

[jmarcum]

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

[SunnyOptimism]

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.