What is this tenacious algae?

[NewWorldViking]

The vitals:
Day 8 of SLAM, FC topped off to 11 morning and dusk. Brushed 3x/day.
CYA 28 (very top of Taylor test vial)
CC usually 0, sometimes 0.5
OCLT down 3 to 4 ppm

Taken pre-SLAM:
PH 7.8
TA 60
CH 80 (adjusted to 250 during SLAM but not yet confirmed via test result)
Temp 66

I have very tenacious algae at a depth of 3ft (likely the winter ice depth) to about 6ft. Pool is 8ft deep. This is after 8 days of SLAM.



I'm continuing the SLAM as the FC is still reacting but visual progress on the algae is very slow. Brushing does not produce any visible satisfying clouds indicating progress. Water is now crystal clear.

Is there anything else I should do to speed this up and insure it doesnt cone back? I've never had algae like this before. It's an unusual year as about 75% of my water had to be pumped out to accommodate a crazy amount of snow and snowmelt.

I'll tell ya, lowering the water level so it doesn't reach the skimmer in 15F through a ft of ice buried under 6ft of settled snow is neither easy nor fun. Do not recommend.
But nothing froze and cracked! Woo hoo!

 

[JamesW]

Looks like iron.

Drop a vitamin C tablet on a spot.

 

[NewWorldViking]

Hmm. Not the color I'd expect for iron.
But I'll get some vit C tomorrow and see what it does.

 

[proavia]

What test kit are you using? Add it to your signature.

It isn't possible to measure a CYA of 28 as the scale is logarithmic and not lonear. Anytime the reading isnxt on a marked line, round up to the next higher number. Your CYA is 30 and SLAM level is 12 for that CYA.

 

[NewWorldViking]

What test kit are you using? Add it to your signature.

It isn't possible to measure a CYA of 28 as the scale is logarithmic and not lonear. Anytime the reading isnxt on a marked line, round up to the next higher number. Your CYA is 30 and SLAM level is 12 for that CYA.

It's right at the very top of the Taylor test vial. I guesstimated that was 28 as it's a bit above the 30 mark, thinking on log scale. But np rounding up to 30.

CYA was lower than that on the first test but I initially supplemented my SLAM heavily with pucks to bring CYA up. They're dissolved and I'm now on liquid chlorine 10%.

 

[proavia]

What test kit?
Add it to your signature.

 

[NewWorldViking]

Nope, Vitamin C tablets have zero effect on the stain.

Test kit is Taylor K-2006C.

 

[BlazeMark]

Three things to try:
1) If you haven't tried, use a stainless steel brush -- you'll likely get faster results. Nylon brushes barely touch this green algae. But make sure stainless won't harm pebbletech. Works great on my plaster.
2) make sure you have good circulation & run the pump continuously while SLAMing. Try to add some of the chlorine at the sites of the algae blooms near the same time of brushing & the remainder at the circulating jets.
3) Consider getting a 2nd opinion on your CYA level. And SLAM accordingly. I assume you are using the Ben's Best Guess chart or equivalent for your SLAM levels.
My CYA readings have been off at pool start up the last couple of years for some reason - even with new CYA reagent. And I use all the Taylor reagents.

And out of curiosity, did your algae problem start before or after using the pucks & what brand are they? After opening my pool (algae free), I was away from home twice this spring and used Clorox pucks (first time ever) & the algae started after that. [so much for the temporary 'convenience of pucks'.]
I finally cleaned the filter, brushed vigorously with my SS brush, got my FC to 20 ppm ( corresponding to my 50 ppm CYA) and am now algae free.

Good luck & hope this helps.

 

[JamesW]

It might be scale, iron and/or copper.

In my opinion, it is not algae.

You can try a stainless steel brush to see what that can do.

Maybe a sulfamic acid or zero alkalinity treatment might work.

Note: Do your due diligence and research on these treatments so that you understand the risks and potential benefits so that you can make an informed decision.

 

[JamesW]

How old is the plaster?

What exact plaster do you have?

 

[NewWorldViking]

How old is the plaster?

What exact plaster do you have?

Replastered Oct 2021. IDK the exact plaster, invoice doesn't specify. It is a smooth matte finish, basic white no pigment if that helps. I'll have to reach out to the guy for more details. No discoloration when closing, it all happened over winter.

I just discovered my pool heater will no longer fire up. It's old and I rarely use it. No leaks. I'm wondering if that may have something to do with this.

 

[JamesW]

Jacks Magic

jacksmagic.com

Stain ID Kit | Jacks Magic

jacksmagic.com

 

[NewWorldViking]

Jacks Magic

jacksmagic.com

Stain ID Kit | Jacks Magic

jacksmagic.com

Thanks, didnt know that Stain ID kit existed. That would be really helpful. I have a SS brush and the ID kit on order. It will take a bit to get here so I'll update once I test.

I'm stopping the SLAM as I'm passing the OCLT and this doesn't appear to be organic.

 

[NewWorldViking]

@JamesW
Got the test and tested. Looks like the Iron Scale Treatment will do the trick.

Copper & Scale Solution #2 did 90% of the work with an obviously bubbling reaction. Following up with Iron, Cobalt & Spot Etching Stuff Solution #1 got it just a little bit better. Sol #1 did little on its own and O2 Safe Shock Solution #3 did nothing.

Edit: Ignore this paragraph and pic. Figured out it's not from the Stain ID test.
I did get some white stuff floating on the surface after the test. Hard to see it in the pic, the dark spots are shadows from the floating white stuff. I guess that's the scale that was removed and needs to be filtered out?


So is following the Jack's Magic Iron Scale Treatment instructions the way to go at this point? Anything else to know?

BUT...
Before I do that I will be repiping my equipment to remove the pool heater from the equation. I'm 95% sure that's where the scale came from. Also a nice excuse to add diverter valves for future solar heating panels.

Speaking of diverter valves, I see a wide price range. Is this a "you get what you pay for" thing or are some just overpriced?

 

[NewWorldViking]

Oops, ignore the floating white stuff. On closer inspection I had some fluffy cotton ball like seeds float in during testing and didn't notice. Didn't come from the test.