My SLAM

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6/28/15

6.30 am
FC - 24
CC - 0

added 19 0z

Really bad eh? Lost 9 ppm over night. So does that mean I have a really long way to go , or can this thing turn really quickly into good results. Still have perfectly clear water and CC of zero , which I guess is something.

Are there other things I should be doing like scrubbing the sides or cleaning the filter?

thx
 
simonoaks said:
6/28/15

6.30 am
FC - 24
CC - 0

added 19 0z

Really bad eh? Lost 9 ppm over night. So does that mean I have a really long way to go , or can this thing turn really quickly into good results. Still have perfectly clear water and CC of zero , which I guess is something.

Are there other things I should be doing like scrubbing the sides or cleaning the filter?

thx
Click to expand...
The very good news is that it can turn around very quickly and your SLAM is done....just keep at it.

Now, on the not so good news (but still not bad) you need to revisit the SLAM article in Pool School and follow everything in their to a T. It will tell you about brushing, filter management, etc. You will soon have a troublefreepool
 
6/28/15

7.10 am
FC 28.5
CC - 0

Anyone have any idea why pool calculator says I need 77oz to raise from 24 to 28.5 but it only took 19oz for me to do it??? Very confusing and means I cannot use the calculator for keeping the SLAM at 28. So all guess work - which defeats the whole purpose of this.
 
Can you confirm what percentage bleach you are using? Because I entered 12K on the calculator with a NOW and TARGET number you mentioned above, and I was given the following: 8.25% = 80 oz; 12% = 58 oz. So this would lead to the following options to consider:
1 - The bleach % was not accurate at times or did not match the calculator as entered
2 - The pool volume used is not accurate
3 - Error I one or more of the tests

Even to lose 9mm overnight is quite a bit. Not so sure you lost that much before did you? So I can't help but wonder if something was different during this morning's testing. You've bee extremely diligent in your efforts with notes and postings, so I know that seemly unlikely, but looking at everything together, something just seems a bit odd. Just trying to help you crack the code on this one.
 
Yes, it is odd.

Had the same think last night - added 26oz to go from 26.5 to 28 and it jumped to 33.

I am using 11k as pool size as on another thread on here , someone used two different calculations and came up with 10900 each time for my pool.

I have been careful in my testing and did the morning one twice.

Will see how it progresses through the day and do another overnight tonight.

Just cant figure out the bleach thing. Using standard publix supermarket bleach that says 7.85 %.

Even with changing calc of pool size or bleach % , numbers are still way off.

The reason I started all this was because a week ago, I lost 2 ppm overnight. So yes, 9 seems high, particularly as water is so clear - i can see 28 feet under water one end to the other , clearly , with mask on , and can see even a tiny flake of leaf at 6ft end from poolside.

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One thing , does the dpd poweder of 2 scoops need to be exact ? I ask because for some reason, even though I keep tge scoop try, it seems to go wet and crystalize on the scoop after a few tests so tiny scoop whole gets colgged and bigger amounts get put in the pool sample than exactly 2 tiny scoops.
 
The powder needs to be dry and use two level scoops for the most accuracy. Not sure how you're conducting your tests but I've found it's better for me to go get a water sample then test in the house where I keep the kit & supplies. Only test I do outside is for CYA & I make sure my back is to the sun to read it. Hope that helps. Hang in there! :)
 
6/29/15

9.30 am
FC 26
CC 0

Off to gym now , will test again when I get back. This pool baffles me - it was only 2 weeks ago that it was perfect. And the fact the CC is 0 and the water is crystal clear, makes it hard for me to understand how the FC is dropping so fast.
 
In that case, yes, you did the poolmath calculator correctly. I used 11K this time and also confirmed with 7.85%. As for the scoops, here are a couple other discussions about that very issue you might find interesting:
DPD FC Test Accuracy - best method for testing
FAS-DPD Test
nitpicky fas-dpd test question

While I have never personally seen a bleach at 7.85 percent, it is still very close to the most common 8.25%, so that shouldn't be a big factor. But depending on your local store, and the source they get their bleach, you might want to make sure it is not too old. There is usually a date stamp on the bottle. Sometimes it is in Julian Day format (i.e. 15120 .... 15 = 2015 and 120 is the 130th day of the year, about 30 Apr).

But definitely read those threads above. They may help you with the FC testing.
 
If you're losing a lot of chlorine overnight, you can rule out UV degradation from the sun. Which leaves organics. Have you seriously scrubbed out behind the light, and beneath and behind and inside ladders and steps? Could there be a lot of debris in the skimmer, strainer, or filter? Bleach will try to oxidize leaves and twigs away. Just because they aren't in the pool doesn't mean they aren't still in the water.
 
I have a screen , and get virtually no leaves . I do not have a ladder , but just built in solid plaster steps. Will scrub the light. Nothing in skimmer - rarely is , cleaned filter before starting and will do each day of doing this.

Thanks for advice , will do deeper 'dive' so to speak on the cleaning and testing.

Two weeks ago, I even went round pool with toothbrush scrubbing any black algae off the tiles that trim round the pool
 

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Texas Splash said:
In that case, yes, you did the poolmath calculator correctly. I used 11K this time and also confirmed with 7.85%. As for the scoops, here are a couple other discussions about that very issue you might find interesting:
DPD FC Test Accuracy - best method for testing
FAS-DPD Test
nitpicky fas-dpd test question

While I have never personally seen a bleach at 7.85 percent, it is still very close to the most common 8.25%, so that shouldn't be a big factor. But depending on your local store, and the source they get their bleach, you might want to make sure it is not too old. There is usually a date stamp on the bottle. Sometimes it is in Julian Day format (i.e. 15120 .... 15 = 2015 and 120 is the 130th day of the year, about 30 Apr).

But definitely read those threads above. They may help you with the FC testing.
Click to expand...
Thanks! At least I know I am doing the testing right.
 
6/28/15

1.00pm

FC 26
cc 0
PH 7.6
CYA 60

So, maybe some progress being made? It has not dropped in 3.5 hours , although , it is pretty cloudy with only about 30 mins of sunshine in that time. Now there is a storm about to hit, so I will have to hold off on my planned scrubbing with my metal brush pole lol

Thoughts on these latest numbers?

thx
 
Numbers look very good for a SLAM. No need to keep testing your PH while you are SLAMming. The high chlorine messes-up the test. So you can save your reagents. Just focus on keeping that FC at/above 24 like you have been doing and you'll be fine. Pump running 24/7, sweep/brush when you can. Clean the filter too. Leave nothing to chance. Anywhere water flows, consider it contaminated with algae to where you need to physically clean and/or ensure bleach can get to it. Hopefully you'll see a good string FC tomorrow morning.
 
06/28/15
tested 3 times got 21, 23.5 and 26 respectively. CC still zero. Now I have no idea . Did EXACTLY same amount of pool water each time, from the same sample. Powder obviously differs a bit as it is impossible to be consistant with it, and it apparently does not matter.

All of this is futile, particularly the overnight test, if I cannot get consistant readings. Do not even know if I should add any bleach right now ! Thoughts ?
 
Ok,

Just scrubbed with brush, did see 'dust' like particles cloud up briefly as I swept bottom. Cleaned usual parts including skimmer and filter.

So, here is something interesting, even since we moved to this house , I can see small (about 3mm diameter ) black patches on the bottom, at the deep end, some a bit bigger. So I just got a mask and spent the last hour with a screwdriver and toothbrush getting them up. They were dark black and I guess algae of some kind, clinging to the roughness of the pool surface. They would not simply come up with toothbrush, so used the point of the screwdriver and literally twisted back and forth and it all broke up and floated in the pool. Got every one I could see. Do you think all this black organic stuff could be what is eating my FC?

I think, that basically since taking over my own pool, I am correcting everything that was done wrong and not dealt with by those before me. I know that all my pool person was doing for last 2 years I have been here, is just add CL tablets in the float thing each week.

So now, on top of taking off all the black stuff of the cement of the tiles 2 weeks ago, I seem to have got all the stuff cling to the bottom of pool now too. Think that might help?

Added 14 oz of bleach to kick all the black stuff I got off. Will test again soon.
 
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So I think there might be some black stuff around the light, but not sure. I do not think it works anymore so might need new lamp. With that in mind, how do pool lights work - can I just take off the cover by undoing the hex screws, or do you have to drain pool. I guess I am asking if they are sealed units.

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So I think there might be some black stuff around the light, but not sure. I do not think it works anymore so might need new lamp. With that in mind, how do pool lights work - can I just take off the cover by undoing the hex screws, or do you have to drain pool. I guess I am asking if they are sealed units.
 

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I believe you are correct. I also had some around that ring & after removing the housing discovered that both the niche and housing were slimy messes. I played it safe & turned the circuit breaker off before removing the trim ring & housing. A scrub brush & toothbrush got rid of the slim.
 
6/28/15

7.15 pm

FC - 23.5 then 22 then 24. It is crazy that there is a swing big enough to make the overnight test pointless seeing as that has to detect a 1ppm drop.

Based on reading on here, it seems powder makes no difference , but the sample water can change results even if 1ml out. Therefore, on that last test, I used a medicine syringe and put 2X 5ml in it, and it hit the line perfectly - curve of fill just touching 10ml line . I think I will use that method from now on.

How do other people know they are passing the overnight ok, if the readings can be out by so much when dealing with SLAM levels?

If as stated you can get a 10% swing with just 1ml difference then at 28 ppm SLAM you can be plus or minus nearly 3 ppm - so overnight test is pointless.

So the only way to do the overnight test is to drop FC down lower so that there is a much smaller margin of error - say at 6ppm that same 1ml swing would only make a 0.6 ppm difference and therefore the test can work.
 

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