Mild green algae - Should I SLAM?

[xdriv3]

I opened up my pool a week ago. At that time, the water was clear.

We added 1 whole bottle of shock and let the pump run. It's been running daily. I was not home for a week and noticed that the timer on my pump malfunctioned...

Looking at the sides of the pool, there appears to be green algae. I ran my hand and it easily came off. It had a slimy feel. This is my first year with the pool and I'm having trouble deciding whether or not to SLAM.

Here are my test stats (using Taylor - K2006)

pH 7.4
TA 200
CYA 60
FC 0.2 ppm
CC 1 ppm


Does the last chlorine data make sense?

Prior to adding the shock on opening, I did not test the water. Since adding the shock, I have not tested it until today. I was tempted to add a triclor puck back in, but don't want to raise my CYA anymore.


What is my best course of action? Any advice would be much appreciated!

 

[mknauss]

Were you adding chlorine daily? You must add liquid chlorine each day. The pump and filter do not keep the water sanitary.

You need to SLAM Process. Read the article and follow the steps. Your SLAM level FC is 24 ppm.

 

[Richard320]

Your pH is close enough that i wouldn't waste time trying to set it to 7.2. Just reach for the bleach. A lot of bleach. Enough to take your FC up to 24. Yes, you read that right. And then reach for the pool brush and brush every inch of that pool. If there's a ladder, pull it out and clean it. By then, it'll be time to recheck FC and replenish it to get back to 24.

It won't be surprising if things look worse after the brushing, but it's necessary to break up the slimy biofilm that protects the algae from the bleach.

Then you can sit down with a cold one and read the SLAM Process article in its entirety. You've gotta move fast. You have an active algae bloom and if you don't get ahead of it, soon the water will be green and opaque.

 

[xdriv3]

Thanks for the input... here an update

7/21 AM - FC <1
7/21 PM - Start SLAM -> FC raised to 28
7/22 AM - FC dropped to 18 --- Did pool math -- raised it back up to 29


At this point, is it ok to hold off checking until tomorrow morning or evening? It's overcast today and would be raining later this evening, again. I wonder if the FC drop is dilutional from the rain all of last night. Water looks great though.

 

[mknauss]

The more you test and bring FC back to SLAM level, the faster the process goes.

Up to you.

 

[Richard320]

Rainwater shouldn't affect things too much, unless it's coming down hard enough that neighbors are building arks.

Figure an inch of water is about 2% of your pool. That'll dilute 24 FC to about 23.5 FC. It might not even show up on the FAS-DPD test. Take advantage of the gloom, where you won't lose so much to sunlight.

 

[xdriv3]

Update---

7/21 AM - FC <1
7/21 PM - Start SLAM -> FC raised to 28

7/22 AM - FC dropped to 18 --- Did pool math -- raised it back up to 29
7/22 PM - Dropped to 15 --> Raised it back up to 28

7/23 AM - Did not check
7/23 PM - 12.5 -> Raised up to 28

7/24 AM - 23 -> Left it alone
7/24 PM - Dropped down to 9


The pump has been running 24/7. I'm been using Chlorox 6%. I'm down to a bottle left. I do have some liquid shock (12% sodium hypochlorite), will finish that up.

The pool looks great. It's clear. No more of the green stuff. The wall isn't slimy..

Am I doing anything wrong that's leading to these significant drops? Should I recheck CYA? or any other parameters?

Thanks!

 

[mknauss]

Be aware the Clorox bleach contains polymers that you do not want in your pool. It would be best to use the liquid chlorine 'shock' you mentioned if you can purchase more of that.

Testing and dosing twice a day is going to stretch this SLAM out a very long time.

Try a Overnight Chlorine Loss Test tonight.

 

[xdriv3]

Unfortunate work precludes me from doing it more frequently. I’ll get a head start when I get home tonight.

If I don’t use Clorox, can I use other Liquid bleach Without the other polymers? I’m not near a store that carries shock?

 

[mknauss]

Plain bleach. It is hard to find now. Walmart has a Great Value Cleaning bleach.

'Fabric Protection' is now all the rage in household bleach. It has polymer in it, most likely the same stuff as 'Cloromax'.

 

[xdriv3]

I think I have good news -

7/21 AM - FC <1
7/21 PM - Start SLAM -> FC raised to 28

7/22 AM - FC dropped to 18 --- Did pool math -- raised it back up to 29
7/22 PM - Dropped to 15 --> Raised it back up to 28

7/23 AM - Did not check
7/23 PM - 12.5 -> Raised up to 28

7/24 AM - 23 -> Left it alone
7/24 PM - Dropped down to 9

7/25 PM - 15 -> Raised it up to 28 --> 28 [1 hr later] -> 28 [1 hr later] -> 28 [1 hr later] -> 24 [2 hrs later]

7/26 AM - 24!!! I retested again just to confirm, yes, it was 24. CC was 0.5. Water is clear.

I think I'm done?! Do the results make sense?


I left for work and kept the pool pump running for the day. Will probably turn off when I go home. When I go home to retest, assuming FC at least the non-SLAM target FC 7-9, I can probably leave it alone, correct?

At what point do I retest pH, TA, CYA, CH?

Thank you for the invaluable help!

 

[mknauss]

Sounds like you are done. Keep your FC at or above target level from now on. Test the remaining indicators this evening and pH once FC drops below 10 ppm.

 

[xdriv3]

Sounds like you are done. Keep your FC at or above target level from now on. Test the remaining indicators this evening and pH once FC drops below 10 ppm.

Just returned home from work and immediate checked the FC -- looks like it dropped from 24 -> 8 over the course of the day. Pool still looks great. Per FC/CYA chart, I'm still within FC target (just not shock range).

Is this ok? The sun was out pretty much the whole day today -- so I'm guessing it's from that? The water still looks great.

I'm thinking of just rechecking before bed time -- keep it in target FC and then recheck again in morning and just go about regular maintenance from here on out..

 

[mknauss]

Check your CYA level soon. It may be lower than you think.

Do as you say -------