Worth saving this late in the season?

[ToddGak]

Hi - we moved into a house with a pool in upstate NY in July. This is our first time owning a pool.

Note: the pool did not have CYA in it when we moved in, and I did not and have not added any.

For the first several weeks, we had crystal clear water. Then a few things happened:

1. I had been chlorinating with the pucks left but the previous owner, using the floater device they left. I must have forgotten to fill it, because one day when I tested, chlorine was at 0. I used the calculator to get it back up to the recommended level using Clorox bleach, then continued to use the pucks and kept the FC level within the recommended range. The water was still crystal clear for a few weeks after this.

2. Then it rained. A lot. I lowered the water level.... too much. Then used our hose to refill. I kept our FC at recommended levels but did not put in extra chlorine.

3. The pool turned green. I wanted to SLAM but I had a few things going against me: (1) I hadn't yet bought a proper test kit. I had just been using strips. (2) The SLAM table gives FC related to CYA level. I had no CYA in the pool. Using the calculator, I calculated how much Clorox bleach to add to get the FC level to 10. I kept it there for about a week (as best I could using the strips). The water turned from green to cloudy white and was getting better. My K-2006 kit arrived on day 7. I did the overnight test and passed. There was no green in the pool, just cloudiness which was taking a long time to clear up, but was slowly and surely getting there.

Then all of a sudden, the water is blue-green. Yesterday I vacuumed a lot of green off the bottom, but it is still in the water.

I should mention that there is no metal in our water, according to a test we just had done.

Questions:

1. Did I stop SLAMing to early? What other mistakes did I make?
2. Why did I pass the overnight test only to have the water turn green again?
3. For any upstate NY people: is it worth SLAMing this late in the season? I can't imagine we will get to use the pool for much longer before it gets too cold.
4. Should I add CYA now?

Thanks!

 

[mknauss]

Welcome to the forum! :handshake:

If you were using Trichlor pucks you have CYA in the water. Have you run a full slate of tests with your K2006? Can you post them? What were the pucks? Blue in their name? Is the water cloudy green or clear green?

It would be best to be algae free and stable before closing the pool. Once you post your current test results we can provide some guidance.

I suggest you read Pool School - ABCs of Pool Water Chemistry and consider reviewing the entire Trouble Free Pool School book.

 

[ToddGak]

Thanks! I bought the Trouble Free Pool book.

The pucks are Clorox Active 99 3" trichlor. I put the last of them in the floater yesterday.

As of now, my results are:

FC: 4.6
CC: 0.2 or less
pH: 7.6
TA: 90
CYA: 50
CH: none

Well. I had no idea I had CYA. I guess I was too eager to get started, and wasted a week and $$ with an FC level that was too low. Judging by the Chlorine / CYA Chart, I should have been at an FC of 20.

 

[mknauss]

Great test results. Yes, your SLAM level would be 20 ppm FC. Use liquid chlorine exclusively from now on. Lower your pH a bit to 7.2 prior to starting the SLAM.

 

[ToddGak]

Thanks - will do.

Forgot to answer one of your questions: the water is cloudy green. I can see the bottom, but not as clearly as I should.

 

[mknauss]

Thanks -- it was to check on copper as many pucks have copper algaecide in them. The ones you indicated you used do not.

 

[ToddGak]

One last question. I stop SLAMing when all three are true:

• CC is 0.5 or lower;
• You pass an OCLT (ie overnight FC loss test shows a loss of 1.0 ppm or less);
• And the water is clear.

What is the definition of "clear"? Clear as in "not green anymore" or clear as in "crystal clear/not cloudy"?

 

[DorsalSpine]

Clear as you can lay a quarter on the bottom and read the date it was minted.

 

[mknauss]

TFP Clear in North Dallas - there is water in there

 

[ToddGak]

Ok - So if my sand filter is taking a long time to clear up the dead algae, I should still maintain my SLAM FC level, even when green is gone and I'm losing less than 1.0 ppm FC overnight, with CC <0.5?

 

[mknauss]

That is correct. Sand filters are slow at clearing the pool. You should have minimal additional FC loss over normal even at SLAM level.