New Thread with my results of first test

[Tom.B]

and one more time tomorrow after work to check daylight loss.

Ok, so here's the latest. I did a complete work-up just for the practice.

Free Chlorine 5 (Loss of 1.5 PPM through the daylight)
Combined Chlorine 0.5
PH 7.2
Total Alkalinity 80 (down by 10)
Calcium Hardness 390
CYA (Stabilizer) 55+

It looks okay to me and seems to be trending to where you guys suggest it should be. I added another pound of dichlor (Leslie's ChlorBrite) for good measure... AND THEN... (see below)

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So... I went to do my brushing I do a few times a week and there is still a covering of yellow on the bottom. I have, over the past few years, played it off to be pollen, or sometimes thought that it could just be the early stages of green algae. However, now it's time to take a serious look at what it is and try and catch it sooner than later.

I suppose I need to start a thread in the algae sub-forum (and will if you would like me to), but my question is: How can you tell if it's mustard algae? I don't see any high demands for chlorine, but I don't know if that is an indicator or not.

[PoolDoc]

Mustard algae will re-appear in areas where you've brushed or wiped it off. It is usually on the shady side of the pool, and will appear on vertical surfaces.

[Watermom]

I also think if it was mustard algae you would have probably lost more chlorine today than just 1.5ppm.

[PoolDoc]

Not necessarily, in the early stages.

[Watermom]

Ok. Didn't know that.

[Tom.B]

While I am not sure it's on the vertical sides, it's certainly on the angled sides. However, it's not in a shady area or any real area in particular. It's spread evenly throughout. There are some green/yellow spots on the stairs, but that's all I can see in the way of concentrations.

[Tom.B]

Mustard algae will re-appear in areas where you've brushed or wiped it off. It is usually on the shady side of the pool, and will appear on vertical surfaces.

Is there any way to know for sure what algae I have?

[BigDave]

If it's yellow-ish (brown-harvest-yellow-chartreuse), it lays on the bottom and brushes up easily then returns, and is resistant to chlorine, I'd call it mustard algae.

[PoolDoc]

Is there any way to know for sure what algae I have?

Not really. It's not a species of algae; just a 'behavior' of some algal biofilms. Some years ago, I spent quite a few hours chatting with a senior researcher at Buckman Labs (inventor of polyquat). He told me that every single case of algae he'd studied, including samples from his home pool, involved more than 10 species of algae AND bacteria.

But Dave's description of the 'behavior' is accurate, with the addition that it's (a) often found on the bottom AND sides, and (b) typically is first found in shaded areas of the pool. It *will* 'bloom' and turn the entire pool green if not controlled.

[Tom.B]

Okay then... I suppose that I have it then. I guess I will read about it here and see what I can do about it.