Help with first SLAM

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D&Jplus7

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Jul 23, 2013
19
Lancaster, PA
I need some help with my first real SLAM. This is my first full season as a pool owner and so far it has been a huge frustration and struggle. Finding this site has been the first encouraging step thus far so a big thank you to those that keep this site running! The pool started turning cloudy and then green a few weeks ago. I found this site last week and made an attempt at a SLAM without a good test kit by using the results of tests at 2 local pool stores. I added bleach 3 times the first day and once more the next, but I'm not sure I added enough any time and the first day I waited a couple hours between each shock. That was last weekend and since I have let the pool sit out of frustration and also because I knew I needed a good test kit or I was probably going to waste more money.

So now my pool is a light to somewhat dark, cloudy blue; improvement, but I still can't see the bottom of the deep end, only half way probably and I know there is still a problem. I vacuumed early this week and removed a decent dirt/algae film off the bottom, although I couldn't see what I was removing in the deep end.

My TF-100 came today and I completed my first round of tests with a plan to SLAM starting Friday afternoon. Here are my results:
FC, CC = 0
PH = 7.0
TA = 110
CH = 430
CYA = 50

So I know that I need to raise my PH first and will do that with Borax tomorrow or Friday before I SLAM. Using the Chlorine/CYA chart my shock FC should be 20. Does the presence of algae and cloudy water skew the CYA results? I didn't try running the water through a coffee filter first so I'm wondering if maybe my CYA may actually be less than 50. Any concerns with the CH being a bit high?

I'll be making a clorox or liquid chlorine run tomorrow to pick up supplies. Any suggestions or comments on my results and how best to proceed are greatly appreciated. I'll provide updates this weekend as the SLAM progresses.
 
Actually, you are in better shape than you think.

You can leave your pH alone and SLAM at that level then tweak it after the SLAM....for several reasons, that's what I would suggest.

Your water will not skew the CYA test. SLAM using 50 as the value....so your SLAM FC will be 20.

No worries with your CH, either. Just like your pH is just a bit low, your CH is a bit high but it will have no affect on the process. Do keep an eye on it the remainder of the season, though.

Get a bunch of chlorine/Clorox and you are all set. Follow the SLAM article carefully but, from your post, it looks like you already have. :goodjob:
 
1. The chlorine is just ever so slightly more effective at low pH....not much, though

2. It adds one more step to your process and usually newbies do better with the least amount of steps.

3. pH of 7.0 is low but acceptable.

4. Most pools tend to rise in pH naturally so it may be a bit higher anyway when your SLAM is finished.

All these are very nuanced reasons...."splittin' fine hairs" as we say in the South. I am a big fan of not getting overly complicated, so will always try to save a parameter adjustment when advising newbies.

It is just fine to elevate your pH if you feel the need.
 
Great! Thans for the information. I'm just trying to learn as much as I can. I'm all for simplifying the process so I'll skip raising the PH until after if it is still necessary.

I'll be raiding local stores tonight for clorox. The pool calculator is showing 965oz for 8.25% which comes out to about 8 - 121oz containers. I know I can go back out and get more, but I'm thinking I want at least 16 available for the first two rounds. I've read to have 4 times the initial shock amount, which would mean 32 containers. Any thoughts on what would be a good initial purchase?
 
Welcome! :wave:

It might behoove you to look around at the hardware stores. This time of year, the pool supplies are stocked in a big way and sometimes the 10 or 12.5% stuff works out cheaper than the 8.25% chlorox. You'll get fewer strange looks if you buy mass quantities of pool chlorine instead of bleach, too. :wink: And places like Lowes have flatcarts that you can stack the stuff on rather than a plain shopping cart.

The low pH will probably correct itself by the time you're through. All the agitation from the pump running so long as well as the 110 TA should fix it.

We like pictures, by the way.
 
So I went through my first afternoon/evening of SLAMing. I wanted to post my progress and see if anyone has any thoughts.

Based on my test yesterday with no FC or CC I started at 3:00 this afternoon with a FC shock of 20 and used 5 gal of 12.5%.

3:45 Test: FC = 1.5, CC = 2; added another 5 gal of 12.5%
4:30 Test: FC = 13.5, CC = 1; added 3 - 121 oz of 8.25%
5:30 Test: FC = 13.5, CC = 1; added 3 - 121 oz of 8.25%
6:30 Test: FC = 14.5, CC = 1; added 2.5 - 121 oz of 8.25%
8:15 Test: FC = 14.0, CC = 1; added 3 - 121 oz of 8.25%

I brushed the pool before I started and then once more in the middle of the process. The pool is now a more murky blue color and looks better, but I still can't see the bottom of the deep end. It seems like the chlorine is still fighting something and I'm not counting on the OCTL to provide positive results. I guess I'll just start fresh tomorrow morning. I have not backwashed the DE filter - is that something I should do before I start up again tomorrow? Any other thoughts?

Thanks,
 
Pressure has been consistent since I started. Pool water looks similar this morning except for a noticeable film on the bottom that I am going to vacuum out. Measured chlorine at 7:15 this morning: FC = 8.5, CC = 1.0 so I added another 4.5 - 121oz 8.25%. I was hoping to see quicker results, but I guess I just need to keep up the SLAM. Running out this morning for more chlorine.
 

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You are not quite adding enough chlorine to raise it up to 20 ppm. You want to stay at or slightly above 20 as long as possible. The chlorine is being consumed quickly at first due to all the algae. As the chlorine kills the algae it will take less to maintain the 20 ppm level. By not keep it at shock level, the process will take longer.
 
Update on my SLAM:

I treated it consistently every 1-2 hours Saturday & Sunday. Brushed both days and vacuumed on Saturday. I checked this morning and the water is definitely looking as good as it has in a few weeks. Still not clear, but closer. The CC was 0.5 or less all yesterday. The OCLT lost a bit more than 1ppm this morning, but it was close. I won't be able to test as frequently today, but will go home to check over lunch and then again in the evening. So I'm passing 1 of the 3 tests and the other 2 appear close. I'm hoping maybe tomorrow will bring success, but if not I can at least tell it is working and I'm close.

After all this work and time spent it boggles my mind the way the pool stores just throw out their recommendations, i.e. buy 2 L of algaecide or 6 pounds of shock and you'll be good! I wish I found this site at the beginning of the season and I could have saved a lot of time, money & stress.
 
D&Jplus7 said:
After all this work and time spent it boggles my mind the way the pool stores just throw out their recommendations, i.e. buy 2 L of algaecide or 6 pounds of shock and you'll be good! I wish I found this site at the beginning of the season and I could have saved a lot of time, money & stress.
Click to expand...
It is amazing, isn't it? BTW, that quote pretty much solidifies the fact that you're a true BBB'er.
 
I am working on this same very same thing. Just bough t a home with a pool. Looks like the pool hasn't been open in a year and a half (Mesh cover). Paid $150 for someone to open.... I don't have a good FAS-DPD test kit (on order) and I tried the SLAM process with little luck. However, reading this I see that I am not using enough chlorine and gave up to quickly. And I have not maintained due to inadequate test kit and my pump kept losing prime.

Anyways, this thread has renewed my drive and my pump is working now. So, as soon as I receive my test kit I will SLAM with renewed intensity!

Also, my initial run-ins with the 'pool store' has led me to believe that they pray on ignorance to buy their products and use their service. Eg. the first thing I was told is that I need new sand in my filter. The next was to buy their $200 bucket of shock, and when I stated I was using bleach I was told to at least buy their liquid chlorine as it's 20% and household bleach is 3%. I later found out their liquid chlorine is 12.5% and my household bleach is 8.25%, not that it matters, nor did I take the time to explain it to them... They also did not know what a FAS-DPD test kit was...
 
Update:

Getting a little frustrated, but trying to be patient. CC has been at 0.5 or less for over two days now. I didn't notice much of a difference in the appearance of the water this morning, but it could just be minor. I still haven't passed the OCLT: it decreased by 3ppm overnight. I'm at work and my wife is busy this week so the best I can do is test/treat in the morning, over lunch and then 1-2 times in the evening. Maybe that is the reason for the delay in seeing this to a conclusion. It just seems close, yet I can't get clear water or pass the OCLT so it is definitely frustrating. Will keep it up today and as long as needed.
 
D&Jplus7 said:
Update:

Getting a little frustrated, but trying to be patient. CC has been at 0.5 or less for over two days now. I didn't notice much of a difference in the appearance of the water this morning, but it could just be minor. I still haven't passed the OCLT: it decreased by 3ppm overnight. I'm at work and my wife is busy this week so the best I can do is test/treat in the morning, over lunch and then 1-2 times in the evening. Maybe that is the reason for the delay in seeing this to a conclusion. It just seems close, yet I can't get clear water or pass the OCLT so it is definitely frustrating. Will keep it up today and as long as needed.
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It didn't turn into a swamp overnight, and it always takes longer to clean a mess than make one. think-i-may-have-found-my-fc-demand-issue-t65957.html
 
Went home at lunch today and could see the bottom of the deep end for the first time in weeks! :cheers: However, I noticed film and what I'm assuming is some clumps of algae on the floor so I did a quick brush job to stir that up and then I couldn't see the bottom anymore. :( FC dropped about 5ppm in the 6 hours since I checked it this morning.

I'm trying to understand the chemistry behind FC & CC. If I'm consistently reading CC of 0.5 or less, what is causing my FC to drop at night? CC above 0.5 indicates the FC is breaking down something, correct? So if I'm getting low readings the FC shouldn't be used up. Maybe that is not the correct interpretation. I'm just curious how it all works together.

I do have two lights so if the water clears up and my CC results stay good, but I still can't pass the OCLT then maybe I need to look more closely at them.
 

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