What is this brown comet looking stuff?

[ssddforever]

Hi everyone!

I'm new pool owner since may of this year.

When we bought the house, the pool was already running and after reading on this site and some other literature I had no problem keeping it running for the whole summer (never had any algae problems btw).
Now the problem: I have attached three photos where you can see brown color thing that looks like washed out sediment or something on the bottom of the pool (white plaster). I spotted it a couple of days ago but was busy to address it immediately. So today I got very surprised when I could't remove it with 8" aluminum algae brush.
Please help me to identify what it is and how to get rid of it .

Helpful info: 1. The pool is surrounded by trees, shrubs and all kinds of flora so there is always leaves and tree debris getting into the pool.
2. Test results with Taylor FAS-DPD : FC: 4.5 ppm, CC: 0 ppm, pH: 7.6, TA: 90 ppm, CH: 200 ppm, CYA: 50 ppm.

Thank you very much.

 

[linen]

Welcome to tfp, ssddforever

I am not positively sure, but to me that looks like small pieces of metal got into the pool and the "trail" is towards the deeper end. I would try some vitamin C tablets put in an old sock and set on one of the stains to see if it lightens.

 

[jblizzle]

Welcome to TFP!!!

My thoughts exactly. Anyone spread some fertilizer nearby?

 

[ssddforever]

To linen: thank you for the advice - I'll try that as soon as I get vitamin c tablets - btw does the size of tablets matter? Also, to keep sock in place would putting brick on top of it work?
to jblizzle: I was clearing English ivy around the pool last week and some of soil got into the pool when I was fighting with roots. And now that you asked I think that is when I spotted the stains for the first time.

Is there any chemical stuff like kaboom for bathtubs which would clean it right away? (i'll do my research - thought to ask just in case there is a quick way)

 

[jblizzle]

If it is metal stains, the vitamin c will do it right away. Ideally, you could take a tablet and just rub it in each streak briefly. It should only take a few minutes.

 

[ssddforever]

Thank you, I'll get tablets tomorrow and see what happens.

 

[techguy]

I would guess fertilizer also.. rust stains.