Pink algae (I think?), and trouble keeping FC up

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Carrie.Eg

Carrie.Eg

0
Jun 11, 2015
7
Allentown
Hi there,

I am brand new to the forum, but have enjoyed reading all of the helpful hints so much! I had my pool installed in July of 2011, and have had 3.5 summers of just humming along spending a bunch of money on the pool store chemicals and only really testing my pH and chlorine levels. Well, of course, now that summer 4 has started, I have an issue :( I want to start the BBB method, but need some advice about exactly how based on this strange pink algae that I'm seeing and the fact that I can't keep my FC level above 1-2. I have been using 3" silk tabs, Trichloro-s-triazinetrione, in my skimmer for chlorine, and burnout3, granular chlorine shock, Calcium Hypochlorite, weekly. I did have some ducks in my pool one morning, but chased them away, so I have no idea if that has anything to do with the pink spots. I live in PA, so we have crazy weather from 60 degrees one day to 90 the next, lots of rain, lots of humidity, sometimes lots of sun, sometimes none. I got the TF-100 test kit yesterday, and here are my numbers:
pH=7.2
FC=2.5
CC=1
TC=3.5
CH=575 (yikes, I know)
TA=70
CYA=55

I also tested my fill water, though most of my filling has been from the rain lately, and those numbers are:
pH=6.8
FC, CC, TC=0
CH=225
TA=170
CYA=0

The water is crystal clear, but the pink spots show up every few days around the areas that get the most sun in the pool. I've been running the pump from 9:00 am - 8:00 pm, and I'm having to keep 2 chlorine tabs in the skimmer, and replace them every couple of days but the FC is still barely 2 (I was shocked to see 2.5 today).

Where should I start? Is that really high CH an issue that I should try to correct first? Should I start with baking soda to raise pH and TA? Should I SLAM it to kill the algae? Sorry for the crazy questions, but I'm really excited about getting into pool chemistry and getting my pool balanced!

Thanks!

My signature didn't save...oops! 5,000 gallon, IG, 3' to 4.5' deep, cute little drinking pool ;) concrete w/aquaBRIGHT finish, Jandy 1HP pump, Jandy sand filter, Jandy heater
 
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Welcome to the forum. SLAM is the solution. Raise PH to 7.2 first. After the SLAM, maintain your PH at the low end to help prevent calcium scaling. STOP using the calcium hypochlorite. Your TA is too high already---should be in 100 range or so. Your FC is far too low for your cya level. See the chlorine/cya chart in Pool School. Leaving those tabs in your skimmer while the pump is not running is not a good idea. Those tabs will only serve to raise your CYA even higher-----we recommended liquid bleach or a SWG if you have one for maintaining FC on a regular basis.
 
Thanks! It appears that you were looking at some of my fill water levels though. My pH is 7.2 and TA is only 70, still SLAM though, right? My follow up question is, about how much bleach do you think should be needed to take the FC up to 20-24 for the SLAM based on my pool size?
 
OK, SLAM is underway. I got home from work today and tested my levels again, all pretty much the same, specifically CC @ 1 and CYA @ 60, some visible pink smears on the deep end wall. Using the chart, I came up with 24 ppm as my shock level, so in went the bleach at 7:30 pm. I tested at 8:30 pm and the FC was 27.5 ppm, a little higher than expected, but OK, right? I brushed the entire pool, paying special attention to the corners, edges, light, return, and those little pockets where the "shallow end rope" is supposed to attach. I've always thought that rope was hilarious in my silly small pool, but whatever. I just tested again at 9:30 pm and the FC is still 27.5 ppm. The pool wasn't green or anything, so I guess there really wasn't that much for the bleach to eat up right away? Anyway, I'm done testing for tonight, but will get up before the sun can hit the pool and test the FC again.

Thanks again for the support!
 
This morning at 6:20 am, the FC had dropped from 27.5 ppm to 19.5 ppm, YAY! That means it's eating something up, right? So, I added bleach, tested again at 7:30 am, and it was 25 ppm. Since I'm going to work, I decided to take it just a little bit higher than 25 ppm, so I added another ~8 oz of bleach which should take it to 26 ppm. Can't wait to see what it is when I get home! :D
 
Progress report time...

Monday night I took it to 27.5 ppm, Tuesday morning it dropped to 19.5 ppm = 8 pm loss overnight.
Tuesday morning took it to 26 ppm, by Tuesday after work it had dropped to 14.5 ppm = 11.5 ppm loss during the day.
Tuesday night took it to 25 ppm, by Wednesday morning it dropped to 17 ppm = 8 ppm loss overnight.
Wednesday morning took it to 30 ppm because I knew it was going to be really sunny, after work it had dropped to 16.5 ppm = 13.5 ppm loss during the day
Wednesday night took it to 26 ppm, and this morning it is at 18.5 ppm = 7.5 ppm loss overnight

So, nothing really seems to be changing, it's basically 8 ppm loss overnight for 3 nights in a row. Is it because I can't be home enough, or wake up in the middle of the night, to keep the shock level above 24 ppm? I'm basically testing and adjusting in the morning before work at about 6:30-7:00, right after work (which is really usually between 6-7 pm), and then checking it before bed at 10:00. I didn't have green or black algae, it was pink, so should I be targeting a higher shock level than it says on the chart to get rid of it? PoolMath has that blurb about "Mustard Algae Shock Level" and it says 34 ppm for that. Any advice about what I'm doing? I am brushing it completely everyday, though I don't see that I'm brushing anything away. I backwashed the filter yesterday morning before work. The water is clear. What next? Continuing the same way seems like it's not doing anything, I thought it would consume less and less each day.
 

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Here's a pic of how she looks. I don't have many features that could be harboring algae, 1 wall return, 1 wall cleaner port, 2 floor returns, a main drain, the wall suction relief safety thingy, the light, and those 2 pockets for the rope. The hose you see if where I attached the vacuum hose to the cleaner port so I could get really good circulation during the SLAM.
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you are doing good, every time it drops below your SLAM level of 24 the algae starts growing again, you can take the FC up just below "Mustard Algae Shock Level" whenever your going to be gone for a long period of time... the longer you can keep it above 24 the faster it will go, your pool is looking good so it should be soon but every pool is different and the last 10% is the hardest and longest to get done... have you taken your light out and looked behind it? there have been a lot of people that had colonies of algae back there..
 
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