Identifying & treating surface stains

[cthielen]

Hi everyone,

I bought a house with a pool last year and have been taking care of the pool myself. The house is 15 years old and the pool may be that old but I'm not sure. It's on the smaller side, maybe about 7,000 gallons. It's hooked up to a pump that runs on a timer and has a somewhat helpful robotic cleaner on the bottom.

Keeping the water chemical levels correct isn't a problem, nor is keeping it full. But it has some strange stains that I'd like cleared up. Some are obvious: yellow/greenish stuff that I can brush off usually happens if I let the chlorine run low and the sun was particularly bright. Other stains though, I'm not so sure about, so I took some photos and am hoping the knowledge of this community can help me identify and treat them.

(Excuse the floating plant material in the photos.)

First, on the steps: https://www.dropbox.com/s/8djexu32706k8 ... 5.jpg?dl=0

They have a strange brown spatter. The steps also have some areas that appear much whiter than the rest of the pool.

Another shot of the steps: https://www.dropbox.com/s/oeg27qy6z59k3 ... 4.jpg?dl=0

Next, near one of the two water outlets that come back from the pump (very near the steps in the aforementioned photos): https://www.dropbox.com/s/68jfifigui07h ... 7.jpg?dl=0

Another shot of the water outlet: https://www.dropbox.com/s/76udk0n1fmu7e ... 0.jpg?dl=0

Finally, on the far end of the pool, the bottom is just generally discolored: https://www.dropbox.com/s/ucxqivknt710k ... 9.jpg?dl=0

Does anyone have any guesses on these stains or know how I can find out more? I appreciate everyone's time and attention in helping this new pool owner figure out what's going on.

I should note the individual who owned the house before me rented it out in the last year and mentioned that the renter's "let the pool go" for a while before she brought in professional, weekly service, so I'm wondering if these stains could have occurred then? I do not have photos of when I first bought the house last year to determine if they changed much under my care.

[Denniswiseman]

It seems like algae
Also it could be metal staining as well
What are your numbers?
Do you have a test kit? as you will need to take lots of tests (pool stores and strips aren't accurate)
First step would be to Slam, follow the procedure exactly and don't miss anything or take shortcuts
If there is still staining after slamming rub some ascorbic acid (vitamin C)on the stains to see if it disappears

[cthielen]

Is it possible to be algae if I can't scrap it off?

I used to have a testing kit that involved small vials of water that I counted drops of chemicals into. That ran out and my local store only sold strips. Are the vial+drop kits trustworthy? e.g. http://www.homedepot.com/p/5-Way-Pool-a ... /203796265

I'll post my numbers once I get a better kit. Generally though, my numbers are pretty good though they tend to fall low once or twice a month; it seems the water from my pipes is just a little low on PH/total alkalinity.

Thanks again, I'll post follow-ups when I get the information.

[Denniswiseman]

Is it possible to be algae if I can't scrap it off?

I used to have a testing kit that involved small vials of water that I counted drops of chemicals into. That ran out and my local store only sold strips. Are the vial+drop kits trustworthy? e.g. http://www.homedepot.com/p/5-Way-Pool-a ... /203796265

I'll post my numbers once I get a better kit. Generally though, my numbers are pretty good though they tend to fall low once or twice a month; it seems the water from my pipes is just a little low on PH/total alkalinity.

Brushing algae is part of the slam process
Check out this post on the HDX kit http://www.troublefreepool.com/threads/109326-HDX-PoolMaster-Kits-to-Test-PH-Not-a-good-ideaThe Taylor test kits K2006c and TFTestkits TF-100 are widely used by the majority of pool enthusiasts.
Your numbers should be kept quiet stable for your pool, letting the chlorine run low will allow algae to bloom
Let us know the pool construction and numbers as they are relevant also how do you chlorinate
CL
CC
PH
TA
CYA
CH