Yellow algae after opening

[etreaster]

We opened the pool last friday and saw we have this brown/yellow stain along the entire pool walls and floor that would not brush off. This is our second year opening and last year went smoothly. I have been reading a lot on here the last few days and I think I have mustard algae(MA). I will try to quickly summarize last year till now. What I thought was sand/dirt collecting on the bottom even after I swept and nobody in the pool just may have been MA. I thought I was doing great testing water at LPS and buying granules/pucks and keeping up, I quickly found out on here I made things worse. Last year I was fighting a high pH (7.8-8.0+) despite my LPS testing normal and my CYA was 100+. So, in retrospect from learning on here, my FA level tested 2-4, but was not high enough to combat algae. At closing last year, I emptied about 40% volume, refilled, then emptied below skimmer to winterize to lower CYA. We hire out to open, they shocked it friday, I tested the next day and no FA. pH was >8.0, CYA ~80. Not knowing what the stain was, I placed a puck on the first step (see image) for a few hours and removed...stain gone under puck. So, now I am pretty sure it's organic (didn't know about MA at this time), I shocked to FA 10, swept all areas and it did seem to have lightened. I have shocked, swept daily since. I started out using granules because I knew I was going to drain and refill to remove CYA and have since changed to liquid chlorine. Yesterday goal was to shock to level 30, FA of 29 this evening, 0 CC. pH 7.4. I backwashed, added acid to lower pH to 7.2 and then added a Crud ton of 12.5% chlorine to get FA up to 50+ according to CYA chart (assuming CYA 100 since adding all the granules). I am anxious to see what, if any, change occurs in the a.m.

If you guys agree that this is MA and it will go away in time with low pH and high FA, my plan is to drain 50% of pool to bring CYA to around 50,refill, balance, hyperchlorinate and brush/backwash daily and repeat until gone. If I am correct in this plan, is there any benefit of scrubbing the walls/floor with a chlorine solution before refilling? If this doesn;t completely go away, should I just drain and acid wash now instead of wasting time and money?

I will test water tomorrow...FA level may be too high for my test kit.

Images: tags would not work...sorry
1. Pool steps with circle where puck sat and removed stain.
[url]https://www.dropbox.com/s/zjs8im20h2spsca/IMG_6610.JPG[/url]

2. Pulled back view of steps...steps are the worst part b/c it gets less circulation of water. Top step was not under water over winter. But all pool looks similar.
[url]https://www.dropbox.com/s/6eg7ycf24w6nus6/IMG_6611.JPG[/url]

3. at floor returns...they were stuck one position so, you can see where water removed stain. This gives me hope it will clear with hyperchlorination
[url]https://www.dropbox.com/s/373cnc0dzzllj1l/IMG_6614.JPG[/url]

Thanks

 

[duraleigh]

Mustard algae is not a stain but a yellowish-greenish dust that brushes of easily when you touch it but then reappears in the same place next day. If it doesn't brush up into a cloud, it is not mustard algae.

What does your water look like?

 

[etreaster]

Water is clear, was clear when opened, got cloudy and cleared back up after dropping pH from 8 to 7. When I am brushing it, you can see a cloud follow. Water was clear when I closed. Last year I had what I thought was sand/dirt collect along the same side as the side returns in different piles, I would either vacuum it up or brush it to the floor return, it would come back the next day. I though my kids were tracking sand into the pool from the sand box, but it would show up the next day after vacuuming despite nobody swimming in it.

 

[frustratedpoolmom]

What that looks like to me is organic staining from algae that has imbedded into scale, probably caused by high PH. Would be helpful to know your CH level of your pool AND your tap water.

You may need to drain and acid wash.

Make sure you use correct terminology we don't want to confuse each other or you - you meant Free Chlorine when you typed FA?

 

[etreaster]

I am pretty sure I had scale last year. The first year I opened, I was meticulous in brushing...I had smooth plaster. My cheapo test kit kept registering high pH but LPS kept saying it was normal. Last year I noticed the floor and steps were really rough, back to LPS and looked back into records, tested CH 300-400. This is when I found this site. So, last year I brushed and kept pH low thinking I was doing a good job. I checked CH over weekend and it was 450. Tap water is 10-25.

Yes, sorry, FA = FC, got FC and TA mixed up in brain

 

[etreaster]

OK...I think whatever algae was in the pool is no longer there...High FC remains, did not drop overnight and CC was 0 this a.m.

Questions:
1. The area I left the puck sit did get better...now was that the chlorine or acid?
2. I think, since CC is 0, I have gained all the advantage of hyperchlorination and the stain left over is just that a stain. Now, if this is an algae stain what of these options would be best: 1. drain and acid wash, 2. drain and power wash, 3. no drain acid wash?

The discoloration has improved greatly since opening, maybe of a combination of the chlorine and when I dropped pH too low from 8 to 6.8. The steps are the worst part.

Any thoughts,suggestions?

Thanks

 

[frustratedpoolmom]

You can see if over time with slightly elevated chlorine levels if the staining fades. If it doesn't, you could decide then to drain and wash. Acid washing can shorten the life of the plaster - not sure if power washing would do anything. Since the puck made the stain fade, it was organic in nature and the chlorine removed it.

 

[etreaster]

Update with pics:

I have done a lot since last post. I hyperchlorinated to FC 50-60 (used almost whole bottle to get this number) b/c CYA 120+ and brushed the heck out of it. Did this for 2 days then no drained acid washed for 3 days. In between the chlorine and acid wash I saw little improvement. I dumped 4.5 gal MA into the pool and brushed every 2 hours. Saw little improvement from first 24hrs, the next 12 hrs over night the stain began to lighten. FC was about 30 with 0 CC. I continued acid wash another 24 hrs and reversed with combo baking soda and borax (TA increased and changed to borax). I checked CH after and it was 450-500. I then drained the pool about 7000 gal and refilled with delivered water. This brought CYA to about 60 and CH was 250-300. Over time I want to bring CH down further between rain water and I am going to no longer bypass my water softener and use that water as needed.

My pH still wants to climb like it has since pool was built...I am trying to keep it low 7.2-7.4 but just this AM it was 7.8-8.0, TA 175, acid down to 7.0 and aerate.

FC 15, 0 CC today, I am trying to keep it 15-20 b/c of the mustard algae.

New pics:
Steps: https://www.dropbox.com/s/13didj7kvuuuvj0/IMG_6721.JPG Compare with number 2 above
Step where puck was at: https://www.dropbox.com/s/ifm9urgthauhrsz/IMG_6723.JPG Compare with number 1 above.
Scale on side of wall after was drained:
1.https://www.dropbox.com/s/byohjfzv12zy8sy/IMG_6673.JPG
2. https://www.dropbox.com/s/6er67781hif6uk3/IMG_6674.JPG

Questions:
1. Should I do another run of no drain acid wash now? My thoughts were to wait until end of summer prior to closing, but it hasn't been swimming weather here yet so another round wouldn't be an issue.
2. I have had zero CCs through this process...should I still keep a mustard algae shock level? I am planning to keep a high FC level until swimming season starts to help rid the last of the brown color.
3. Also, how will I know mustard algae is gone...just seeing if it does/doesn't re-accumulate? Is there any way to test if MA exists in the water...what I thought was dirt vs MA.
4. Any other thoughts/suggestions?

Thanks to all....site was a huge help.

Oh...almost forgot. Since I am a believer in the BBB method, I went to return the Frog cartridge and chlorine pack insert that I bought prior to season today. Pool store manager thought I was an idiot. I told him I have new found knowledge and that knowledge does not include Frogs or solid chlorine...my vast improvement in the pool is justification. He said that was the dumbest thing he heard of but he would refund me my $140. It feels good to know I never have to go back there...found everything I need at Wal-Mart/Lowes. Awesome!!!