Cover = algae

yabbyfarm

Active member
Nov 24, 2014
42
Barossa/ South Australia
#1
Hi all,

I have a problem where as soon as my pool is covered I seem to get either very dirty water or an algal bloom.

The pool was crystal clear and maintaining correct PH, TA and never got below the recommended FC level for my CYA.

My would covering the pool cause this problem?
My FC actually went up during the time the pool was covered (3 days), yet the pool looks dirty with a hint of green.

I'm hoping its just dirty but I have a feeling it may be the dreaded algae again..
 

pwrstrk

TFP Expert
LifeTime Supporter
Aug 17, 2012
4,758
Elverson Pa.
#2
What type of cover are we talking about, solar ?
I see in another thread, you were involved in the SLAM Process. Did you follow the process till all three criteria were met ?
Crystal clear water.
CC of 0.5 or less.
Pass the OCLT Test.
If the SLAM process wasn't followed correctly and stopped before all three criteria were met, you won't have killed all the algae off. Also if it's a solar cover your talking about you'll need to make sure it's clean an algae free.
Could you post a set of test results ?
 

Patrick_B

TFP Expert
LifeTime Supporter
Jun 7, 2011
14,999
Midland TX
#3
If it is Algae, you did not have enough FC prior too or after you covered it.

Simply adding a cover will not induce Algae growth, so your FC took a dip somewhere if you are seeing Algae, cover or no cover.
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,082
San Rafael, CA USA
#4
Oftentimes if a cover is dirty or already has algae on it, then putting it over pool water depletes chlorine in the water so then algae can grow. Now in your case with an SWG continually feeding the pool with chlorine, the FC went up because the cover prevented some sunlight from breaking down the chlorine. So in your case I suspect that the cover was dirty and just made the water look dull and perhaps had algae on the cover that at least initially has the water look a little green. If you have decent circulation and the FC level is truly higher and staying that way, then it should clear up between the chlorine and filtration.

To prevent this problem in the future, clean off the underside of the cover before putting it on the pool water.
 

yabbyfarm

Active member
Nov 24, 2014
42
Barossa/ South Australia
#5
Thank you for all the advice.

It doesn't appear to be a full algal bloom. I cleaned the filter and ran it all night and the water does appear to be a lot clearer.
I'll give the cover a good clean today. it is the first time I have used it since I have been testing and maintaining my own pool so you may be right about it having algae and dirt still attached to it. It is the plastic style bubble wrap looking cover, I think it is referred to as a "Solar Cover"


I keep all my test results and filter time on a spreadsheet I'll take a screen grab and upload my latest lot.

Yes I did the Slam process, but you are correct I didn't do it absolutely by the book. I'm still not convinced that I actually needed to slam it because a similar thing was happening before. Chlorine levels where always high and I would only get dirty and greenish looking water if I covered the pool for a few days. I was just doing it as a precaution so I could start fresh. The pool did actually look a million dollars for nearly a week prior to me covering it again for boxing day (I went away).

I have family coming up on the 3rd of January and we would really like the pool to be useable. The weather is forecast is 42degC (107f) so I kinda need it.
Pool Test Results.jpg
Pool Test Results.jpg
 
Last edited:

pwrstrk

TFP Expert
LifeTime Supporter
Aug 17, 2012
4,758
Elverson Pa.
#7
Can you post a pic of the water ? Is it still somewhat green in color ?
If your going to SLAM let's call your CYA level 90 and your shock level is 35. Turn your SWG off. Drop PH into the low 7's first then bring your FC up to shock level.
Follow the process to the T this time. SLAM Process
 

pwrstrk

TFP Expert
LifeTime Supporter
Aug 17, 2012
4,758
Elverson Pa.
#10
It wouldn't hurt to put that cover on for a little while to get some of that shock level chlorine on it.
The water does look green to me a couple of feet out from the edge. Make sure your pump is running the whole time.
 

yabbyfarm

Active member
Nov 24, 2014
42
Barossa/ South Australia
#12
PAGirl - thankyou, I am going off of the test result pre-slamming.

I had the FC level at 35 since about 2pm and made sure it was at 35 again at 9pm. Scrubbed the pool and cleaned the filter.
Overnight the water has cleared up and the FC level is still at 35 (7am). The sun is just about to hit it.
I know according to the Slam process it should take longer but it looks to me like its not loosing any more chlorine and the water is clear.

What is the highest level of FC that you can realistically swim in and not get skin irritation? Its gonna be hot as **** in about 2 days....
 

pwrstrk

TFP Expert
LifeTime Supporter
Aug 17, 2012
4,758
Elverson Pa.
#13
You can swim in FC levels up to SALM level for your CYA level as long as you can see the bottom of the pool. You'll be fine !
No CC's correct ?
Sounds like you've made some good progress on clearing the water. Did you put the cover on to get some SLAM level water on it to help clean it up ?
 

yabbyfarm

Active member
Nov 24, 2014
42
Barossa/ South Australia
#14
Nope no CC's either.

I plan on laying the cover on the lawn and hitting it with the pressure cleaner and some bleach. I don't want it anywhere near the pool until after this hot spell.

Great so I can stop adding bleach and hopefully the FC level drops a little in the next couple of days.

I'll be interested to see the test results after the slam because I had to use 750g 65%Cal hypo because I didn't have enough Bleach at the beginning. I still used about 18L of bleach on top of that. I wanted to avoid the Cal Hypo because I already have too much CH in the water.
 

pwrstrk

TFP Expert
LifeTime Supporter
Aug 17, 2012
4,758
Elverson Pa.
#15
Your CH in the last test was 375. Just keep your PH in check and you'll be good. Your TA is good as that will help with the PH rise from the SWG.
I can understand keeping the suspect cover far away from the pool during the heat wave ! Lol
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,082
San Rafael, CA USA
#17
Is the water a clear green or is it cloudy green? Do you see visible green algae on the floor or sides? Something about this situation doesn't make sense. Do you have any unusual chemicals in this pool -- any metal sequestrants, clarifiers, flocculants, enzymes, algaecides (i.e. copper), etc.? Also, what is the temperature of the pool water?
 

yabbyfarm

Active member
Nov 24, 2014
42
Barossa/ South Australia
#18
I will take a photo of the water once its in full sun today.
I can see no visible algae, the water looks like a cloudy green.
Water temperature goes down to around 27-28 at night and the heater turns off at at 32 during the day.

I have had the solar cover off since the 29th of Dec because I thought it was causing problems, I have since cleaned it with a decent concentration of bleach and have put it back on. The reason being it has been very windy and my pool seems to be filling up with flying deb re from the trees faster than the filter can clear it out. I seem to have to clean out my cartridge filter daily.

The pool shop had me putting in Clarifiers and algaecides when they where in charge of water quality. Since I drained 30% of the water at the start of December I haven't added anymore pool shop chemicals.
 

pwrstrk

TFP Expert
LifeTime Supporter
Aug 17, 2012
4,758
Elverson Pa.
#19
It might have something to do with the algaecide's and clarifier's you added. You stated you did do a 30% drain and refill.
I'm a little stumped also. Let's see if Richard gets back with something.
 

yabbyfarm

Active member
Nov 24, 2014
42
Barossa/ South Australia
#20
Just went out and pulled back the cover (I put in on last night as an experiment).
I ran the filter all night with the in-floor cleaner turned off. The water is now very clear and looking good, however there is a lot of dirt etc on the floor of the pool. So I'm guessing half my battle is trying to stop the pool getting so dirty.

Is it possible that my in-floor cleaner is doing more harm than good?