SLAMing a SWG pool

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I'm not familiar with your specific SWG, but in general, we advise people to keep the SWG off during a SLAM. SWGs are not designed to maintain such high FCs, so it's extra wear on the cell(s). You would be better-off just sticking to the bleach during the SLAM and leave the SWG off. In fact, you might find measuring FC more predictable during this time with bleach only. I hope that helps.
 
surfbabe, Make sure to take a picture each day of their steps looking down into the water. That will help you see the progress as things seem to move slower. The pictures will help everyone see the progress. You can use photobucket to load the pictures.

Kim
 
Ah yes I was thinking that photos would be a good idea...

This afternoon the water is looking great. It is clear and getting bluer. I'm guessing it won't look really blue because the plaster is off-white and there isn't as much water as my pool?

I measured the FC at 18.5 and CC at 1 just now. That's about 3 hours without the SWG going, and there was a 2.5ppm drop.

However, now that the water is clearer, there are marks on the sides that look suspiciously like oldish limescale. Another problem that has come to light is that the owner got fed-up with the sweep hose on the polaris spraying water everywhere so he attached a metal bar :)() to the end of the tail..... it has left scratches on some parts of the plaster and there are dark patches which might well be chipped plaster.

I'm going to go back in about 2 hours to measure again - I'll do the CYA too to make sure that hasn't dropped during the day - just to make sure that we got rid of those nasty cya-eating bugs last night...
 
Well, it looks like the pool is now ok...
OCLT was less than 1ppm and to be honest I didn't get to them until 9.30 so that may well have been uva loss.

FC was 20
CC less than 0.5

I haven't added anymore bleach today.

Next actions?
measure cya and add more to get them to 60ppm?
allow FC to drift down a bit then fire up the SWG?

very happy! Thanks everyone.
 
jblizzle said:
That was a ridiculously short SLAM. The water is crystal clear already?
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it is absolutely clear. The CC this morning was less than .5 and I checked it 2 twice. The FC went down very little at 1ppm overnight.

I figured that it was quick because of the initial shocking we did - 10ppm then testing every 10 minutes. That lasted a few hours and I got through 5 gallons of bleach before it was holding at 10ppm for the 10 minutes.

I've just been back to look at the pool, it looks lovely.

I'll go and test the water in an hour or so.

I've asked the owner to buy CYA in granules and we will add sufficient to get it to 60 ppm. I will work on it being a 10,000 gallon pool- which is what I think it is based on the chemical usage so far.

I will check the CYA, FC and CC - obviously the FC will have gone down today (it's bright sunshine in Austin).

I was waiting for the FC to go down to about 10ppm before switching on the SWG - my rationale was that the FC needed to go down and the SWG working would mean that it took longer for the FC to go down.

Testing the pH? I thought that testing at high FC levels meant that the pH would be inaccurate? I'll test when the FC gets to 10ppm?
 
If initially there was no or very little CYA in the water (and by the sound of it there was no CYA), then a 10ppm FC level has insanely high levels of hypochlorous acid. At those levels. Not only would the kill rates be very rapid but you'll oxidize just about anything in the water. The fact that the water cleared so quickly is a bit unusual as that is what typically prolongs most SLAMs.
 
surfbabe said:
Thanks Matt. The water was pretty "clear" when we started. Just turquoise.
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Ok. That makes more sense. Sound like you headed off a full-out algae bloom. Green swamps take a lot longer to clear because you have to kill everything in the water AND then you have filter out all the dead solid waste which tends to be the longest phase.
 

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JoyfulNoise said:
Ok. That makes more sense. Sound like you headed off a full-out algae bloom. Green swamps take a lot longer to clear because you have to kill everything in the water AND then you have filter out all the dead solid waste which tends to be the longest phase.
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phew!!!

you guys are just awesome!

What do you think of my next few steps?
reduce FC to 10ppm
check cya - add more to get to 60ppm
turn on SWG
check pH

check salt level?
 
surfbabe said:
phew!!!

you guys are just awesome!

What do you think of my next few steps?
reduce FC to 10ppm
check cya - add more to get to 60ppm
turn on SWG
check pH

check salt level?
Click to expand...

Sounds fine to me. You can check and adjust CYA now though. High FC will not affect the results of that test.
 
Here is the pool this evening.
Test tonight showed .05 CC 11ppm FC (that went down quite a bit during the day from 20ppm) I turned on the SWG tonight , CYA 40 - I will check this tomorrow again since it showed as just under 40 this time whereas last time I checked (yesterday morning) it showed as just over 40.

In the photo, you can see the polaris very clearly at the bottom of 6ft of water.
 
I could not have done it without you guys. :salut:

They are very happy. The owner has a birthday in just over a week - she's having a party at her house and this is my present to her. :cheers:
That first step of the lack of CYA and FC - well I wouldn't have caught that and would have just SLAMmed as usual. Out of interest, what would have happened? Would the SLAM just not have worked? I would have still monitored the FC so would have been adding the chlorine but not every 10 minutes and I would have added the CYA just prior to the SLAM.
 
Well, if you added more CYA, it may have converted to more ammonia creating a high amount of chlorine to get rid of it. And if you were only testing every few hours, then you just would have been adding the chlorine much more slowly and it would have taken longer to remove the ammonia and kill everything off.

The regular SLAM would work, just take a lot longer.
 
I would also check out that Jandy swg if it's an aquapure and make sure it's functioning. The tri sensors go fast in them, I've had at least 4 or 5 over 9 years. I'm about to try the newest version and see if they work any better.
 
keastman said:
I would also check out that Jandy swg if it's an aquapure and make sure it's functioning. The tri sensors go fast in them, I've had at least 4 or 5 over 9 years. I'm about to try the newest version and see if they work any better.
Click to expand...
Thanks Chris, will do. How do I make sure it's working?

Tonight's test results:
FC 7.5 - now that is down from 11ppm last night. We have had rain in the meantime.
CC 0.5
CYA a shade under 40 - same as yesterday
TA 70
pH 7.2

The salt level is 5000 on his testing stick which I think is too high?
The SWG has been going since yesterday as well.

We are about to add CYA to bring this up to 60ppm.

Water looks crystal clear.... I'm a bit jealous since it's even clearer than mine.....
 
Their salt level was at 5000, it went up quite a bit during the SLAM. I looked at the manual for their SWG and the optimum is 4000ppm.
I went over the weekend and the chlorine was going down and this evening it was at 3ppm with the SWG going. I'll see what's happening tomorrow with that.

I measured the CYA over the weekend too, now, I'm putting this down to it being rainy/overcast when I took the first reading when we were slamming - today in bright sunshine the CYA was at 30ppm. So, I'm hoping that the difference is in the visibility. I've added 27oz of CYA granules in a sock in their skimmer - this should be enough to take a 10,000 gallon pool up 20ppm. Pool still looks great.

I'm going back tomorrow to measure the FC and check that it's staying at 3ppm - ie that the swg is actually working.
 

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