Black algae and brown "dirt" stains

[frustratedpoolmom]

If a pool's TA is on the high end (above 90) it tends to cause the PH to creep up. Some pools this happens faster than others, especially when there is a source of aeration (or an SWG). The articles in Pool School are a guideline. This is why we recommend 70-90 for SWG users, and it's a wide range. Some pools will attached spas, or waterfalls or fountains may see faster rise than others and then we recommend the lower end of the TA range.

Since your TA is 90, which is totally acceptable, rather than following the recommended "How to Lower TA" steps in pool school, I'm suggesting you add acid to lower the PH to 7.2 (as the instructions state) and just let it creep up on it's own (because of the SWG) it will likely do this slowly because of your borate addition. There isn't any reason to rush the PH back up via aeration, it will come up on its own. The only reason I'm suggesting lowering it to 7.2 is because it's at 7.7 now, borderline too high.

The alternative is to follow the steps in the article, which I don't think you really need to do, as your numbers aren't bad at all. You could just add enough acid to lower PH to 7.4-7.5, but because you added borates, I don't think you'll see any result from that small amount of acid. Your original question to lower the TA to 70 with acid and then aerate - not necessary and too much acid all at once... But because the PH is borderline high now, targeting 7.2 will maybe yield better results than targeting 7.4. Does that make sense?

With daily PH monitoring for a while, you should get a feel for your PH, see if it rises. If it does, then the TA of 90, while in range, may still be a too high for your pool (every pool is unique). So each time you see a ph of 7.8, if you lower it to 7.2, the acid will also slowly lower the TA as well. Eventually as your TA gets closer to 70 the PH should stabilize. But I don't think it's critical enough of an issue now to follow the typical "How to Lower TA" protocol. Does that make sense?

You may even find now that you added the borates, that your PH/TA end up being pretty steady and you may find the PH doesn't creep up at all, or very little.

I hope this makes sense.

The borate addition has no affect on the CYA. 8 days should be plenty to register. Where did you get the CYA? We've seen some reports of lesser quality - lesser % concentrations too. Has it been 8 days since it dissolved completely, and what method did you add it?

 

[maddog808]

The alternative is to follow the steps in the article, which I don't think you really need to do, as your numbers aren't bad at all. You could just add enough acid to lower PH to 7.4-7.5, but because you added borates, I don't think you'll see any result from that small amount of acid. Your original question to lower the TA to 70 with acid and then aerate - not necessary and too much acid all at once... But because the PH is borderline high now, targeting 7.2 will maybe yield better results than targeting 7.4. Does that make sense?

With daily PH monitoring for a while, you should get a feel for your PH, see if it rises. If it does, then the TA of 90, while in range, may still be a too high for your pool (every pool is unique). So each time you see a ph of 7.8, if you lower it to 7.2, the acid will also slowly lower the TA as well. Eventually as your TA gets closer to 70 the PH should stabilize. But I don't think it's critical enough of an issue now to follow the typical "How to Lower TA" protocol. Does that make sense?

You may even find now that you added the borates, that your PH/TA end up being pretty steady and you may find the PH doesn't creep up at all, or very little.

It makes sense to me to lower the pH to 7.2 now, because I want the TA to be lower (70) to help stabilize the pH. But if the borates might stop the pH from creeping up at all, then shouldn't I aerate to get the pH back up into the 7.5-7.6 range? Isn't 7.2 too acidic for my pool?

What I really was asking was, once I get the TA down to 70, then as pH creeps up to 7.8, should I still lower to 7.2 each time? Or should I follow the Pool School and just lower it to 7.5ish? I think your answer is to monitor my pH, because if I run my spa or waterfall often, then the Pool School method of pH adjustment might not apply.

The borate addition has no affect on the CYA. 8 days should be plenty to register. Where did you get the CYA? We've seen some reports of lesser quality - lesser % concentrations too. Has it been 8 days since it dissolved completely, and what method did you add it?

I got the CYA from Leslie's. They call it "Conditioner", and the ingredients say 99% Cyanuric Acid. It has been 7 days since since it dissolved completely, and I added it in a sock in the skimmer. I wonder if I am reading the test wrong. It seems like a very subjective test. Should I add the solution until I can't see the black dot at all? Or just until it starts to disappear? :?

 

[Bama Rambler]

This is the most discussed test performed on this forum. It takes some practice to get used to reading it.

Here's how it should look.

Notice that when done you can't see the black dot at all.

 

[maddog808]

It seems like I can still sort of see the black dot on the last pic. So if that is considered the "end", then I guess I have more CYA than I thought. I will have to retest tomorrow and see what it looks like. I will need to order more reagent as well. :lol:

Nice pics. Thanks for posting, Bama.

 

[Bama Rambler]

What you're actually seeing is the outline of the bottom of the cylinder. If you notice the "ring" you see is larger than the dot.

You can use the solution to practice several times buy pouring it back and forth between the cylinder and test bottle.

 

[frustratedpoolmom]

It makes sense to me to lower the pH to 7.2 now, because I want the TA to be lower (70) to help stabilize the pH. But if the borates might stop the pH from creeping up at all, then shouldn't I aerate to get the pH back up into the 7.5-7.6 range? Isn't 7.2 too acidic for my pool?

What I really was asking was, once I get the TA down to 70, then as pH creeps up to 7.8, should I still lower to 7.2 each time? Or should I follow the Pool School and just lower it to 7.5ish? I think your answer is to monitor my pH, because if I run my spa or waterfall often, then the Pool School method of pH adjustment might not apply.

I don't think the 7.2 will stay there very long - that's my point... I suspect you will see it rise and hit the mid 7s within a day or two of running the SWG or other features.
If the end result is to get the TA into the 70 range - lowering it to 7.2 will get you there quicker than if you were to target mid 7s and also, because the borates act as a buffer, small adjustments to PH/TA becomes more difficult.

Yes, anytime you see 7.8 or higher, lower it back down. If your TA is 70-80 you can target the mid 7's and see what happens to the PH - you don't have to go to 7.2.