Test results and questions

[Jeffski]

FC .5
CC .5
TC 1
pH 7.5
T/A 120
CH 140
CYA 0
Temp 74

Test results from yesterday. Vinyl inground pool - 18 x 36 with 9' deep end (22,000 gallons?).

I added about 2 lbs of stabilizer yesterday and turned up the swg to raise the chlorine level.

Shooting for 2-3 on the FC reading right?

CC should be zero right? How do I drop that?

Pool has been open for about 3 weeks but I've spent very little time on it due to work. The water is actually clearing up nicely. I have another problem though with possibly mustard algae or something that collects on the seams and bottom of pool. When you brush it it disappears but then settles back down a couple hours later. My wife says it's dirt but I'm sure it's not because it will show up right after running the Aquabot and when you brush it it disappears into a cloud. You can't brush it around like you can with dirt. Anyone know what that is and how to get rid of it? It was a problem all of last year also.

Thanks in advance.

[CarlD]

If you have an FC level of .5 but a CC level also of .5, you need to shock your pool. At the moment (until your CYA level stabilizes) you need to bring that chlorine level up to 10ppm and keep it there for a couple of days. Then the SWG can do it's job.

[Watermom]

It could be dust or dirt that is settling in the seams and bottom of your pool. My pool does that. When I vacuum or when we swim it gets stirred up and you can't see it. But, then when the water settles down, it will often resettle again.

[aylad]

It could be dust or dirt that is settling in the seams and bottom of your pool. My pool does that.

Mine does, too.

Janet

[Jeffski]

I'm sure it's not that though because I can vacuum or run the Aquabot and the bottom of the pool will be covered hours later.

[aylad]

Dirt or pollen is like anything else that's not soluble in water.....if you stir it up, as with the vacuum or Aquabot, then let the water get still, what didn't go into the filter will settle back down in the bottom.

However, if you're sure it's not dirt, you could try swimming down to a particularly dense area of whatever it is, and use an eyedropper to get a sample. By putting it into a jar or glass of water, it might be easier to identify.

Are you using chlorine overnight? By that I mean have you tested your Cl at night after the sun is off the pool, and then tested again in the morning before the sun hits it? That would give you a true idea of how much chlorine demand you actually have....and if it's none, then the stuff is dirt. If it's algae, you'll see a dramatic drop in the Cl level from night to morning.

Janet

[Jeffski]

I understand what you're saying, but if I run the Aquabot for 4-6 hours for three straight days and the bottom of the pool is still covered hours later it has to be algae, right?

Anyway, yes my SWG was not getting my chlorine up over 5 so I dumped in a bunch of Clorox and now it's up to 10. Yes the chlorine is dropping overnight and I have .5 CC's which hasn't gone away (should be zero right?). So I am going to keep the SWG at 100%, run the pump 24/7, and add chlorine as needed to keep it up around 10 for several days. Is this safe to swim in?

Also, when you ask about chlorine levels dropping overnight what you're really asking is if they are dropping when the pump isn't running and the SWG is off...is that correct?

One last thing...I added about 3lbs of stabilizer because I was getting a zero reading. I think it's testing around 20 right now and I was targeting 50ish. How is having a low CYA reading, or none at all, affecting my pool right now as I battle this algae?

Thanks everyone.

[aylad]

Are the sides of your pool covered with this stuff you think is algae, or is it just the bottom? And how much chlorine are you losing overnight in ppm? My vote still is dirt, but I could be wrong. I can tell you that just because your Aquabot has been used that much, you can still have dirt settling in your pool, but if you really think it's algae, then the only way to get rid of it is to shock it and keep it shocked until it goes away. I just hate to see you waste that much chlorine if it's not really algae. Also, if you're going to shock it and maintain that shock, you need to do it with chlorine (bleach)--the SWG can't keep up with a maintained shock level and you're putting a real draw on the cell life. The SWG will be much better at maintaining a baseline chlorine level than it will maintaining shock level (which is 15 ppm, now that your CYA is 20,not 10--if you're only going to 10 ppm, you're not going to win the battle if it is algae).

As far as your stabilizer goes, I don't know by which method you added it, but it can take several days for it to completely dissolve into your water, so I wouldn't add any more until you've waited a couple of days and re-tested for it. Having the lower CYA reading is better than having none at all--you do have to maintain a slightly higher shock level, but at least you're not losing it all to the sun. Most people with SWG keep it around 80 because it's supposed to optimize cell life, but while you're shocking with other forms of chlorine to clear the pool, I would keep it on the lower side for now.

Janet

[Jeffski]

I appreciate your advice. No the "algae" is not on the sides of the pool, it settles on the bottom...kind of in clumps. If it's dirt then I have a bad filter right? I mean seriously, running the Aquabot 6 hours a day and vacuuming every 3 days really should get the dirt out. I'm sure it's something else.

[aylad]

Algae grows on the pool sides, often before it grows on the bottom.

Janet