Closing The Green Lagoon

[bcroft21]

I've been bad this year...we have had a full blown green lagoon for months. I know this can NOT be good for anything in the pool, but I'm finally making time to take care of it. This pool is at a house we are renovating so not having it directly in my backyard has proved a major hurdle in keeping up with it. After struggling during the middle of the summer, I gave up, but I don't want to let it sit like this the entire winter.

We live in South Carolina and last year left it open and would run the pump here and there, but it stayed crystal clear all winter with very little care. It did collect some debris so we are considering putting the cover on this winter, as part of the struggle this year was not having a good vacuum to get all of the leaves out of the bottom, which contributed to the ongoing struggle with keeping the water balanced (could only vacuum on waste, so water being pumped out, new water being pumped in, small algea bloom, bleach, repeat - just a nasty cycle I couldn't get off).

There is a LOT of algea buildup...like it's thick on the pool floor and somewhat thick on the walls. Where do I even begin?

 

[zimm]

Edited- I saw you already have the TF100 test kit....

What are you test numbers? You will need to SLAM the pool (extended "shocking"). But until we know the CYA (stabilizer) level of the water, you won't know how much chlorine to shock to.

 

[bcroft21]

Just took the readings and got...

CYA - 60
TA - 50
pH - Off the chart, as expected
Chlorine - no reading, also as expected

I started the SLAM process earlier this summer but was not successful. We live just down the road from the house but not being there 24/7 makes it challenging. I've read some folks are up in the middle of the night taking test readings? I guess I need to check out the SLAM page again and re-read up on the process to make sure I can get it right this time. Looks like the PoolMath calculator is telling me I need to add Muriatic Acid and Baking Soda? Not seeing it calculate anything for bleach. I'm not sure why this SLAM process always gets the best of me, but I really think a good hand-holding once through will get me there. Any suggestions?

 

[duraleigh]

pH - off the chart????

What color would you describe it? Regardless, that will be mandatory to get back in the 7's

 

[kcindc]

Once you finish the SLAM, would you consider putting in a SWG? This will help keep the FC up when you aren't around. A SWG will still need attention, but you wouldn't need to be around every day.

1. Adjust PH to 7.2 ASAP, after you add muratic acid (MA) to bring down PH, retest to make sure it is at 7.2 Best to do the MA additions in steps, so that you don't overshoot your target.
2. You should make sure that you've removed all of the debris (leaves, etc).
3. SLAM, put your details into Pool Math and scroll to the bottom of the page and it will tell you your FC shock level. It is best to test FC and add bleach hourly at first. Once you are able to hold FC, you will test and add bleach less frequently. I image you will be loosing FC pretty quickly at first.

Defeating Algae:
http://www.troublefreepool.com/content/126-defeating-algae

SLAM:
http://www.troublefreepool.com/content/125-slam-shock-level-and-maintain-shocking

 

[bcroft21]

Thanks so much for the detailed info kcindc. I know I will be away this entire weekend...should I wait to start SLAMing until Monday morning? I'll be able to tend to it much better that next week but don't want to start now and lose momentum being gone for about 48 hours.

duraleigh - pH was BRIGHT, neon pink

 

[duraleigh]

A test result of pink would not be "off the charts" for pH. It would indicate a pH in the 7's.

pH you cannot measure would be purple for too high or very yellowish for too low.

I am not sure why you expected it to be out of range. Test again and match it to the color block to the best of your ability.

Do not start to SLAM until you confirm an acceptable pH.

 

[kcindc]

It has been a swamp for a long time, so I wouldn't bother SLAMing until you have free time to attack it hard and frequently. In the mean time, stock up on a lot of plain bleach. Wal-mart brand is a pretty good source, fresh and cheap. Don't store the bleach outside as it will start breaking down before you are able to use it.

You might want to bring down your CYA to 30 or 40 by replacing some water. The lower the CYA, the more effective your bleach will be at combating the algae. A higher CYA will mean you need to have a higher FC which will mean more bleach.

 

[bcroft21]

I re-tested the pH and got the same thing...very, very bright pink. Just a bit darker than the top of the pH scale. It definitely did not identify with anything close to 7 on the test tube.

So, my goals before SLAMing are to...
- Lower pH to around 7 using muriatic acid
- Lower CYA to around 30-40 by replacing some water

Then, SLAM away? And then once (more like, if, based on past experiences) I have a successful SLAM, being in the south our options are to either cover it up and let it sit stagnant until the spring, or leave it open and run the filter occasionally? Still not sure what the best bet is there.

 

[Smykowski]

Yes, but the only change I would make is to aim for 7.6 until you get something resembling a reading on the scale, then bring it down to 7.2 - when making large pH changes, you want to do it in steps so you don't yoyo around.