white clouds while brushing

Ferd

Active member
May 21, 2020
29
Washington DC area
Hi,

When I brush - especially if I do on the pool's bottom - small, white clouds appear and then go away. I've tried to browse the forum for similar problems but haven't found a solution. We have been in the house for just a month, so I'm just really taking control.

Here's what I know:

- the previous owner used about 2-3 pounds of calcium hypochlorite 70% once a week, plus trichlor tablets in the skimmer. My initial tests indicated FC~9-10, CYA~50. I have stopped using it and now I use just trichlor tablets, plus bleach as needed if I test low FC.

- when telling him about the white cloud, the owner also said not to brush too often (I told I do it once a week; that was way too often for him). I think this is what he was doing in the past.

- I found the original description of the vendor, year 2014. The pool has a marbelite finish which is a mix of marble and white cement. The recommended calcium levels are between 220 and 300. The calcium level i've tested in these weeks has been always in the range 200-220. Yes, I need to raise it.

Here's a recent test:
FC 6.5
CC 0
CYA 40-45
Ph 7.6
TA 100

Are these clouds a source of concern? do they indicate plaster damage in progress?
 

needsajet

TFP Expert
LifeTime Supporter
Jan 4, 2016
4,731
Sydney, NSW, Australia
More than likely dead algae, at least that's the first thing to rule out. Start with Overnight Chlorine Loss Test and we can take it from there.

Remove the trichlor floater while performing the OCLT (i.e. no other sources of chlorine during the test)

Low calcium is a surprise if it's had a lot of Cal-hypo added, unless you've had a lot of rain or refilling. Maybe double check that test.

Nice to meet you via TFP :)
 
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Ferd

Active member
May 21, 2020
29
Washington DC area
Nice to meet you too! hanks. I’ll do that tonight.
I retested CH at 260, I must have done something wrong. Previous owner’s explanation of the white dust was indeed that it’s a residue of the powder shock he used to put. But I haven’t put it in for a month now.

In the meantime, a couple of questions:
- If it’s dead algae, how can it be that:
— I loose little (<1) FC even during the day?
— i always test 0 CC?
 

Ferd

Active member
May 21, 2020
29
Washington DC area
Hi Richard,
yes, I'll run the test tonight. I do vacuum every week. I can't say if the small clouds have been getting smaller, but that's another thing to track maybe.
 

Ferd

Active member
May 21, 2020
29
Washington DC area
Hi all,
I run the test, and lost 0.2ppm (at most) from 7.30pm to 6.30am. That seems fine to me.

James, nice to meet you here at tfp. When I rub my hand I notice very small clouds, let's say half an inch wide. I have to rub hard to get them; but I see no residue on my hand.
 

needsajet

TFP Expert
LifeTime Supporter
Jan 4, 2016
4,731
Sydney, NSW, Australia
The combined chlorine result tells us other things, but nothing about algae. Glad to hear you had no chlorine loss overnight and sounds like perhaps the dust is clearing up with vacuuming? What is your filter pressure before and after backwashing? How often (roughly) do you backwash?
 

Ferd

Active member
May 21, 2020
29
Washington DC area
@needsajet: Before I vacuum, the pressure is around 20-21. After I vacuum in the morning, if I wait until the evening the pressure might get to 27-28. I backwash once per week after I vacuum.

One (related?) thing I need to report is that the pool has only one working skimmer - the other one had a leak and was filled with cement several years ago.

@JamesW: the previous owner answered saying that it wasn't painted, but it was plastered - details above. He repeated he believes these white clouds are because I brush too often - he's been here more than 15 years I think, I need to air what he says as well I think.
 

JamesW

TFP Expert
Mar 2, 2011
20,417
What is the CSI?

Can you show a good picture of the surface?


 

Ferd

Active member
May 21, 2020
29
Washington DC area
Ok, pool thermometer on the way, will know CSI on Sunday or Monday. I'll read in the meantime a little more about it.

A picture is below. Sorry it shows up gigantic - the forum system said not to shrink it or it might upload it incorrectly (tips welcome!)

Also, here's a short video of the white clouds:
. I thought it could be useful.

F868DF7D-C9E2-4E96-A096-023CFE0BDCBC.jpeg
 

Ferd

Active member
May 21, 2020
29
Washington DC area
Hard indeed. The owner said it wasn’t painted. Now, while I wait for CSI, really the only concern is whether it could be anything that indicates a problem. If you guys can’t think of anything, that’s probably good enough.
 

Ferd

Active member
May 21, 2020
29
Washington DC area
Hi all,

hope you guys had a great weekend! So, here's the tests results with CSI included:

- FC 7.6
- pH 7.3 (I just added soda ash)
- TA 80
- CH 220
- CYA 45
- TEMP 31C
- CSI -0.41

Does this tell you anything about whether these clouds could be a sign of some damage in progress?
 

needsajet

TFP Expert
LifeTime Supporter
Jan 4, 2016
4,731
Sydney, NSW, Australia
I don't think your water is damaging the pool. Raising pH is a good decision. Also fair to mention it will rise on it's own unless you're using trichlor pucks. Something around 7.8 would be good.

You can use the 10ml test for FC, where one drop = 0.5 ppm FC.

Your pictures (thanks!) look like dead algae carcasses to me. My theory is a filtering problem. Since you don't know the history of the pool, your filter may just be channeled (water flowing through pathways with little resistance and cleaning effect) because the sand gets kinda caked up inside. To clean and reset the sand, we do a deep cleaning. It uses a fair bit of water and perhaps an hour or so to take the multiport valve off (10 mins), hose out the sand (30+ mins), and replace the multiport valve (10 mins). It's light work, but messy due to the waste water running over the neck of the filter. Pool maintenance companies will say "your sand needs changing" which is not true, but has the same effect in the end. If money is no worry but time is, it's easy to get a pool company to do this.

Here's a link with all things 'filter' and also the filter cleaning method Deep Cleaning a Sand Filter

After that, you'll establish a new "clean" pressure. Let the filter get dirty (clean pressure times 1.25 or even a tad more) and it will filter really well.
 

Ferd

Active member
May 21, 2020
29
Washington DC area
Hi - sorry it took so long, got swamped at work. Thanks! I looked at the video and read a bit around.

I thought dead algae carcasses might just dissolve with the clorine; is that wrong?

Below you'll find a picture of the top of my filter (no, the pump was not running). The pool inspector described it as "ancient" when he saw it, but also said that they last forever so not to worry. I don't see any screws to take away the top - does that tell you anything about how likely I am to open it and not mess it up? Pool super-novice here ;)

IMG_1105.jpg