A little help Diagnosing some spots

[tmisleh]

We finished our owner/builder pool up about 6 months ago and I thought all was well.

I downloaded Pool Math, set up my subscription, and started logging my tests. The water has stayed crystal clear since day one, and for the most part, I've been diligent on the maintenance and chemical balance. About 3-4 weeks back, I started noticing small amounts of green algae around the stairs and assumed it was just a dead spot in the circulation..... I started digging into TFP more and realized I had made a big mistake.... I hadn't done a single SLAM the entire time I've been running. DOH! I remedied that this past Monday and got my PH and Alkalinity back under control today.

In my idiot move, I think I may have helped some kind if Algae take hold.... I've started noticing small dark spots (about dime-sized) here and there (pics attached). They're never in clusters, pretty circular, and they do not come up at all - even with a vigorous and prolonged pumice stone attack. I'd like to figure out what these things are, stop any new ones, and remove the ones I've already gotten. Any help would be appreciated!

Complete pool details:

Link to Logs: PoolMath Logs

- Pool located beachside in Central Florida
- 18,000 Gallons with spa
- Gunite shell
- Saltwater Generator (Jandy Aquapure 1400) set to 85%
- Pump runs 8 hours a day (8am - 4pm)
----
* No screen, and it gets direct sun all day long (no overhead vegetation)
* We also built our pool with about 2' of it above ground so we can create some different levels in the yard down the road
* Our pool water is frequently in the 88 - 94 degree range
* We do have hard water (from an artesian well) - but we had a company run it through filters before filling the pool
* Primarily testing with Taylor K2006 - supplemental tests with strips when I'm in a hurry

 

[zea3]

Hi, welcome to TFP! You can set your poolmath app to share your test data with TFP in the settings, then when we hover over your avatar we can look at your logged test results. If you have been keeping the chlorine within the target values for your CYA you shouldn't need to slam the pool. It may not be algae you are seeing. It could be stains due to other factors, such as rebar too close to the surface or fertilizer with iron blown into the pool. Have you tried crushing a few vitamin C tablets and tying them up in a piece of cloth and laying them on the stain? Let it sit for a while and see if the stain lightens.

 

[tmisleh]

Hi, welcome to TFP! You can set your poolmath app to share your test data with TFP in the settings, then when we hover over your avatar we can look at your logged test results. If you have been keeping the chlorine within the target values for your CYA you shouldn't need to slam the pool. It may not be algae you are seeing. It could be stains due to other factors, such as rebar too close to the surface or fertilizer with iron blown into the pool. Have you tried crushing a few vitamin C tablets and tying them up in a piece of cloth and laying them on the stain? Let it sit for a while and see if the stain lightens.

Thanks for the quick response. I have the app set up to share, so I'm not sure why that's not working at the moment :/ I'll troubleshoot it. On the VItamin C, I haven't tried those yet. I did see that recommendation on another thread and was planning to give it a shot this weekend.

 

[tmisleh]

Just tried the Vitamin C tablets on one of the spots. I used an entire tablet on a spot that is roughly 1/4" in diameter and there was no change. Ugh :/