Don’t Judge! Tons of algae

JF July

Member
May 17, 2019
23
Nashville, TN 🎶
FC 0
pH 8
CYA <30
TA 80
Mucho algae (floating & at the bottom)- doing mustard shock levels after initial SLAM just to be sure!

Just used my test kit for the 1st time. I’ve read & made notes on Pool School articles, but want to make sure I’ve got my order correct before dumping chemicals:

1.) add Muriatic acid to lower pH to 7.2
2.) CYA in sock by the return, until CYA is 30-40
3.) SLAM
- Add chlorine to bring it to shock level (12-16, if CYA is 30-40)
- Retest FC & add chlorine at least 2x/day until CC is 0.5ppm or lower & it passes OCLT
- Brush & vacuum thoroughly 1x/day
- Backwash filter as needed

Do I need to do anything to adjust TA? How much chlorine should I have on hand before starting? (I only have 9 gal of 10% currently)
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
22,069
San Dimas, CA (LA County)
Welcome! :wave:
Step 1 is correct.
Step 2.... go back and think about your test results. Did it get cloudy at all? Do you think it's zero, or could it be 15 or 20? Use that as your basis to determine how much stabilizer you need to get CYA to 30. From that point on, consider your CYA to be 30 and SLAM at 12 FC. It's easy to add more of you're low, but lowering it later can be a PITA.
Step 3, mostly correct. I would say add chlorine every couple hours the first day.,You'll kind of know by how much is left when you retest. If it's all gone, you need to increase the frequency. If most of it is still there, you can stretch the interval some.

TA? It's fine. After the SLAM, everything will need rebalancing. When you add acid to lower pH, you'll lower TA a little, too. It'll fix itself.

How much depends on how big a pool. A 40,000 gallon builtin will need a whole lot more than a kiddie pool.
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
22,069
San Dimas, CA (LA County)
Sorry, I think my Signature will post now.
It does! :goodjob:

Since it looks like it'll take 3 of your gallons to get you started (Don't wait for the CYA to fully dissolve, go ahead and slam) you probably only have enough there for the first day. Go stock up and get another 6 or 8 gallons. It'll get used before it goes bad if it's too much for the SLAM.

Note: if you adjust pH with acid and start brushing, you can recheck pH in as little as fifteen minutes and get moving on things. Friday night is a great time to start a SLAM, since you won't lose any FC to sunlight the first few hours and you'll be around to monitor the filter pressure.
 

JF July

Member
May 17, 2019
23
Nashville, TN 🎶
I didn’t start until 5pm tonight. Used Pool Math to calculate all additions.

- added muriatic acid (59oz of 31.45%, 20*)
- Started CYA socks at 5:30
- Added 3gal 10% chlor at 6:30

Then I brushed most of the pool before testing pH again. It’s still 8.0! Pool Math recommends another 59oz MA. Does that seem right?
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
22,069
San Dimas, CA (LA County)
I didn’t start until 5pm tonight. Used Pool Math to calculate all additions.

- added muriatic acid (59oz of 31.45%, 20*)
- Started CYA socks at 5:30
- Added 3gal 10% chlor at 6:30

Then I brushed most of the pool before testing pH again. It’s still 8.0! Pool Math recommends another 59oz MA. Does that seem right?
Yes.
 

kimkats

Mod Squad
LifeTime Supporter
Jul 10, 2012
41,319
Tallahassee, FL
Your pH might be higher than you think. You will need to go into battle mode for it:
-Test
-Pool math to bring it from 8 to 7.5
-add acid with pump on high and brush the pool
-wait 15 mins.
-Retest

Keep doing this until you see the pH in the 7s

Kim:kim:
 
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JF July

Member
May 17, 2019
23
Nashville, TN 🎶
FC loss overnight was 1.0. Levels this morning:
FC 11 (goal is 12)
CC 0.5
pH 7.2
TA 50
CYA assumed to be 30

Water is blue, but murky enough that I can't see the bottom. Ive brushed, vacuumed, backwashed when pressure increased 25% or more. Pump is running 24/7. Am I doing something wrong?
 

zea3

Mod Squad
TFP Expert
LifeTime Supporter
Jul 10, 2009
11,720
Houston, Texas
No, it is normal for the filter pressure to rise. It is filling up with debris and will need to be backwashed more frequently during a slam, as you will experience a 20% rise in pressure more often as the dead algae filters out. Keep adding chlorine to stay at 12ppm as often as you can, a minimum of 3 times a day and more if you can manage it until the slam is finished. Everything sounds like it is going as it should. It just takes sticking to the slam protocol and patience at this point. Sounds like you are doing great!
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
22,069
San Dimas, CA (LA County)
Sounds right. Sand filters are the slowest about clearing the cloudiness. The chlorine demand should have fallen way off, so it shouldn't be that big a deal to keep it up and let the filter work. Keep brushing, as that keeps the debris in suspension so it can get drawn into the skimmer and filtered. If you're going to be around to watch the pressure, you can add a little DE as mentioned in the SLAM Process article. AIf you won't be there, don't try it. DE filters load up FAST.
 

kimkats

Mod Squad
LifeTime Supporter
Jul 10, 2012
41,319
Tallahassee, FL
Take and share a pic of the pool looking down at the deep end so we can see where you are at. Put your brush down so you can see the progress as you can see more and more it it!

I will tell you the last part of it clearing seems like it is the longest!!!

Kim:kim:
 

JF July

Member
May 17, 2019
23
Nashville, TN 🎶
Day 6, Still murky!
I only seem to be losing FC to the heat & sunlight (93F yesterday with no clouds!)
***What should I do if I plan to be away a couple of days?

FC 11.5 (lost 0.5ppm overnight)
CC 0
pH 7.2
TA 60
 

zea3

Mod Squad
TFP Expert
LifeTime Supporter
Jul 10, 2009
11,720
Houston, Texas
Right before you leave, bump it back up to shock level. If you can keep the pump running while you are away the filter can keep pulling stuff out of the water. How long are you able to go between backwashes now?
 

JF July

Member
May 17, 2019
23
Nashville, TN 🎶
No, no one. 😟 It's enough to ask the neighbor to take care of the chickens, the dogs & our pet turkey. So I got one of those hth floating chlorine dispensers just so it doesn't go to 0 while we're gone. I guess I'll just check & balance everything upon my return.