Losing chlorine and worried about SLAM because of metal staining history

Kstots

New member
May 20, 2021
1
Georgia
Pool Size
28000
Surface
Vinyl
Chlorine
Liquid Chlorine
I have used this forum over the past couple of years to help with pool problems as they have come up, but never fully jumped in to the whole process. I am sick of chasing my chemicals every summer and still never feeling like they are balanced, so here I am with questions and concerns.

We have a 28,000 gallon pool with a sand filter. I have been battling metal stains on and off for 2 or 3 summers now. I get the metal under control in the spring and the pool does well over the summer, but I lose control to algae and leaves in the fall and let it go for the winter and then have to battle back in the spring again with algae and metals that fall out when I shock for the algae. We live in GA, so I typically don’t close the pool for the winter. Not an ideal situation, but again, here I am.

This year I was able to get ahead of the metals early and used Clorox Scale, Metal, and Stain remover to pull the stains, then let it filter for several days and used Bioguard Sparkle Up to help filter the metals out. At the same time I also added HTH Algae Guard because there was also some algae. It has stayed sparking blue for about 2 weeks, since shortly after I added those, but I am burning through chlorine.

I have added as many as 6 bags of shock at a time. At one point I did it twice in one week, which was also the week I had the metal dropout and staining. Now I am adding 1-2 gallons of bleach at a time, and can’t keep my chlorine at a good level for more than a day. I thought at first it was because I had used the metal remover, because in years past I have used vitamin C and it takes forever to get my chlorine up at all, but based on my research the remover should not have this effect (though please correct me if I’m wrong). Now I am considering other options.

Our pool only gets full sun from 12-3pm and is almost completely in the shade before 11am and after 4pm. Last year I forgot to regularly check CYA and I was running through chlorine until I figured out my mistake late in the season and realized my level was <30. I don’t usually use the pucks because they don’t ever seem to help keep my chlorine up. For the past couple of summers I will put 5 pucks in a floater and unless I am adding 1 or 2 gallons of bleach every week my chlorine stays <1. I have been more diligent about keeping CYA up this year and am currently at around 40. I did the overnight FC test last night and it was at 3.0 at 8:20pm and was at 1.0 at 9:10am.

Prior to starting the overnight FC test we put the solar cover on the pool for the first time this year . I tested the pool at 7:10pm and the results were as follows:

FC- 1.0
CC- <.5 (Very pale pink)
PH- 7.4
TA- 90
CH- 190
CYA- 40

These results were after putting 2 gallons of 5.25% bleach in about 24 hours before and it was 4.0 that morning. After the above testing I added 1 gallon of 5.25% bleach, which brought my FC up to 3.0 after an hour, which is where I started my overnight FC testing. Also, I tested FC again tonight after a sunny and 80 degree day with the solar cover on all day and the FC is 0.5. I haven’t added any more bleach, because I need to go buy more and want to get enough for the next steps. Based on everything I read on this forum, I think I need to SLAM, but I am kind of afraid to because of the metals. Also, I have a hard time keeping my pH up, as it was 7.6-7.8 just a couple of days prior to this testing. Any advice or guidance would be appreciated because I really want to get these chemicals well balanced and enjoy our pool this year instead of being frustrated by it.
 
Welcome to TFP :)

You have been having all kinds of pool store fun... We need to get you going.. Here is what you need to do TODAY... Forget everything you have done with your pool.. You are going to start now using TFP... Metals are not my area so that will have to be someone else helping you through that.. I can get you through the SLAM :)

You going to need gallons of liquid chlorine in 10% or 12.5%, exactly how many is unknown, lowes. HD, Atwoods, Local stores, sometimes pool stores.. check many places as some are cheaper than others..

What test kit are you using, your numbers look good to start a SLAM.. CYA is the hardest test, are you sure it is at 40? Once you start your SLAM you are only testing FC and CC.

1. You poured Ammonia into your pool (HTH Algae Guard) it will take some time to get it out.. Using PoolMath Using liquid chlorine in 10% or 12.5%, put 10 fc into your pool until your FC stays at 10 more than 30 minutes..

2. once FC stays at 10 FC take it to SLAM FC/CYA Levelslevel of 16 for CYA of 40. Test as many times a day as you can, I try to test every 2 hours.. the closer you keep it at 16 FC the faster the SLAM goes... Because you have metals you will have to do Overnight Chlorine Loss Test after a couple days because your water may turn green.. Once you pass all 3 tests of the OCLT your SLAM is over and you can deal with the metals...

Once your SLAM is over you need to keep FC level above 5FC at all times... from the FC/CYA Levels your Minimum is 3FC, that is a CLIFF, never drive off a CLIFF.. You will have to SLAM again if you fall off the cliff..

So when you test FC in the afternoon it should be above 5FC so you would put in enough liquid chlorine to get you to 7FC or 8FC so when you test the next day you are above 5FC... once you get this down you will be good and because you do not close down you do this every day... In the winter (water temps below 60 degrees) you can go a couple days between putting chlorine in but it is still the same thing, never go below 5 fc..

I hope this helps and gets you going. :)
 
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