First real test results + first signs of green algae - advice appreciated!

[cmp455]

First, thank you so much in advance to anyone who is able to offer advice. We became new pool owners last summer, and an algae issue completely got away from us. We followed advice from the pool store and spent 6 weeks trying to fix it before closing it for the winter and never really enjoying use of the pool.

Luckily, the water has seemed in relatively good shape since we opened it this year, and when someone recommended this website and the test kit I was so happy to have an actual method to rely on instead of guesswork. I have done a first round of testing and these are the results:

FC: 2.5
CC: 0.5
pH: 7.2
TA: 70
CH: 250
CYA: less than 30, which was the lowest the vial went to. I input 28 to PoolMath to get a recommendation but not sure of exact number.

PoolMath is recommending I add 2 pounds of Borax 20 Mule for pH and 1 pound, 7oz of dry stabilizer for CYA. When I read the instructions it said to put in a sock in the filter - dumb question, is that an actual human sock or is that something I buy at the pool store?

And, my main question - coincidentally on the day of the first real chemical test, I saw just a few traces of green algae in one part of the pool. Should the above additions and chlorine maintenance be enough for now to take care of that, or should I be going to SLAM or something more extreme at first sight of algae?

Also, we have been using the chlorine tabs instead of liquid chlorine at recommendation of previous owner. I'm guessing we should stop that and use measurable liquid chlorine instead?

Thank you, thank you, thank you in advance - I am such a newbie at this and appreciate any help people can offer.

 

[jeffchap]

Your pH is fine. Forget about the borax.

If you can still see the dot with the tube filled, your CYA is 10 or less. Add enough to raise it by 20 ppm. Put it in a regular human sock and suspend it in front of a return for it to dissolve. Consider your CYA to be 30 for now for all future calculations.

If you can see algae,you need to SLAM now before it gets any worse. Your SLAM level will be FC 12. Test and dose as often as possible until no algae is visible. Hourly is best if you can. Use only liquid chlorine (bleach).

Read the full procedure here: SLAM - Shock Level and Maintain

Once the water is perfectly clear, perform an Overnight Chlorine Loss Test and post your results. At that time we'll see if you can end the SLAM.

 

[cmp455]

@jeffchap thank you so much! This is really helpful, I will follow your instructions.

Are containers that say liquid shock ok to use or is that different from liquid chlorine/bleach?

 

[jeffchap]

They should be the same thing, just possibly different strength. Be sure they say sodium hypochloride and they'll usually be anywhere from 6% to 12%. Put in the proper strength when calculating how much to use in Pool Math.

If you ever use laundry bleach, avoid the splashless and scented kinds. They will make your pool foamy for a few days. Avoid Clorox Chloromax too. It has additives in it we don't want in the pool.

 

[cmp455]

@jeffchap Thank you so much! I did what you recommended and it is looking pretty good to me. Water is totally clear and bottom and sides were clean after brushing/vacuuming.

Last night at 9pm, FC was 9.0 and CC was 0.5. This morning at 5am, same numbers - FC of 9.0 and CC of 0.5. There was a bit of black sediment on the floor this morning, so I brushed it and kept added more chlorine to SLAM level before work just to be on safe side. Still looking good now (6pm).

I added the recommended amount of stabilizer in a sock. It is almost dissolved but I haven’t tested CYA again yet.

Should I do another overnight test tonight or does it sound like it should be good? Or do I need to do CYA or pH tests to be sure?

Thank you so much! Compared to our six weeks of pool store cycling last year this was so much easier and already seeing quick results.

 

[jeffchap]

If you passed the OCLT last night, there's no reason for you to do another one tonight.

It would be a good idea to go ahead and test your CYA again just to make sure that it is at least 30.

Assuming that it is, allow your FC to drift back down to 5 and try to keep it there with daily chlorine additions. Never let it drop below 3 and you should be good.

Continue testing FC everyday or two for a couple of weeks just to make sure it's holding. After that, you should have a pretty good feel for how much chlorine you need to add each day to maintain it at 5 ppm. At that point you can drop back to testing once per week.

At the same time, test your pH once per week and use muriatic acid to lower or baking soda to raise it to stay in the range of 7.2 to 7.8.

Congrats on a successful SLAM!