Mustard Algae? Pollen?

[BrandonD]

So I started off strong with the TFP method... but really started to slack off, and went so far as to let my pool go over the winter without so much as the pump running. About 2 weeks ago I started it back up again. Ordered a refill kit for the TF-100, used a net to scrape what I could off the bottom (couldn't see), and added enough stabilizer to bring it up to 50ppm. Only, from past experience, I poorly assumed I was at 0ppm CYA, but in reality I was closer to 40ppm. When I had the refill kit I tested it and I was up at 90ppm... ugh.

For the last week and a half or so I said screw it and SLAM'd it with the outrageously high chlorine levels. My fill source is well water, and when we filled it originally it took a while to get the yellow tint (iron) out the water. I did not like the idea of draining 44% of the water to get it down to 50-60ppm. I assumed over time with friends and family using it I'd get the CYA back down with top offs, as in the past it's something I've had to periodically keep up on.

Anyway, the SLAM hit a wall about a week in. No noticeable improvement. After the first day or two of the SLAM, the filter color went from the dark algae green to brown. Almost like I was filtering out iron particles again. The filter would also hit the gotta-clean-it PSI within a few hours, even up until a few days ago. Despite the filter only looking 40% or so brown when I cleaned it.

The wall and the weird filter stuff caused me to suck it up and drain about 44% of the water. While it was down to that level I got in and scrubbed the walls, railings, and staircase. Everything had a light brown tinge to it. We get a LOT of oak and pine pollen during the off season when the pool sat for several months without circulation. Is it possible I'm dealing with pollen here? Would you do anything different other than re-start the SLAM when the water level is back to normal (it's filling up now.)

Thanks.

 

[Texas Splash]

Your problems are two-fold - algae and iron. No question. Pollen isn't really even a factor at this time if at all. The water went brown once you increased FC which is also validates what you're getting from the well. Unless you can truck-in fresh water with no iron, you have to manage the iron via a sequestrant. But first ...... you have to eliminate the algae. You can't treat the iron (brown tint) until you know the algae is gone by passing the SLAM completely. Once that's done, then you can carefully manage pH and FC, along with sequestrant, to try and prevent another iron precipitation outbreak.

So for now, focus on the SLAM. You didn't post your test results, but first make sure the pH is at about 7.2. Then, based on your new/current CYA, increase FC to SLAM level. Once you pass the 3 SLAM criteria, you can let the FC drop to normal and start managing for iron (filtering, Sequestrants, etc). Pool School - Metals in the Water and Metal Stains

 

[BrandonD]

Sounds good, thanks. I just questioned what the brown was because I hadn't filled the pool up with the well water at that point, aside from a few inches or so to top it off. Is it possible there were still iron particles in there, despite it being crystal clear for a couple years since getting it out from the original filling, and the water chemistry caused it to precipitate again?

 

[Texas Splash]

I would say yes, the iron was always there. Filling a pool from well water often leads to iron. Perhaps your iron level is low. If it is, that's good. But when you let the pool sit for the winter and ended-up increasing FC for the SLAM, it "angered" the iron. :grrrr: ha ha. It's a balancing act since every pool and amount of iron from a local well is different. But once you pass the SLAM, you should be able to lower the FC to your normal range and start effectively treating the iron. During the SLAM, you can't use sequestrant, but you can filter (i.e.rags in skimmer) to help catch what precipitates. I would also recommend brushing often to try and keep the iron from staining too badly. After the SLAM, the brown may fade away since it was not an issue before. You can also use the sequestrant which should help keep the iron precipitated in the water to prevent staining.

 

[BrandonD]

Thankfully the staining isn't that bad. The only spot I can tell is the wall behind the cake stairs and the underside of the stairs. I pulled it to the center of the pool while cleaning today as it has a knack for collecting debris. The wall behind it was stained to a dark brown. Taking a brush and rag to it brought it down to a light brown. Can't see it behind the stairs anyway. Despite the water level being down 44% I couldn't see the bottom extremely well (especially after I started cleaning and knocking stuff around), so hopefully it isn't stained.

Not too worried about the battle with the iron. The first time I was, but if I can get it crystal clear with a 100% fill, shouldn't be a problem with 44%... hopefully...

 

[BrandonD]

No regrets with the empty/refill. It was already clearer than before even after filling with the iron enriched water. A day or two in I could see the bottom, and today it's even better. Not much longer. I have a refill for the CYA reagent coming today so I'll test the CYA and hopefully I hit my mark with the refill. The last few days I've just been dumping an arbitrary amount of chlorine in until I can start the SLAM again knowing the CYA level.