quick validation please

[Bigsteveg]

We went on vacation for a week and guess what, we had a dirty pool when we got home. I think the issue is that we overheated the pool right before we left, pool temp was around 86 degrees. I noticed a little algae before I left, dumped some shock (power bag from sams club) in and went on vacation. FC was around 10, little high haven't gotten a perfect mix of run time / SWG % yet. Pool activity also messes with the % I think as well.

Measurements:
FC 15
CC .5 (possibly less, the color barely changed but went clear when we added one drop)
PH 7.3 (started the summer at 7.2, I figured aeration would have brought it up higher but hasn't yet)
TA 80
CH 110
CYA 60
Salt 2800 (test) 3100 (from computer)

FC loss is around 2-3ppm but haven't done a good test since I've been home. Dusk to early morning I mean, I've tested during the day and early morning but not at dusk to early morning.

Right now, the water is just cloudy so I may have killed the algae but not sure.

My plan of attack, just want to confirm this sounds right:
Get the FC using liquid bleach to 28 and maintain for the day. Check the next day for FC drop and continue shocking until that doesn't drop more than 1 ppm.

 

[Bama Rambler]

That's not a bad plan, but it's not really following the SLAM pprocess. You should wait until the water is clear to perform the OCLT. Also don't for get to turn the swg off during the OCLT or the results will be invalid.

Having said that, you can perform an OCLT whenever you feel like it. So, if you want to do it tonight, it's perfectly fine, just don't lower the FC from shock level until the pool is clear.

 

[BoDarville]

I think the issue is that we overheated the pool right before we left, pool temp was around 86 degrees.

This probably has nothing to do with the algae/cloudy water. More likely, it has to do with the SWG %. On my recent vacation, water temps were between 86-90°F and I came back to a crystal clear pool. I was careful to maintain the proper FC, though.

Was your CYA of 60 ppm measured before or after you added the powdered shock? The Sam's shock (like many powdered "shock" products) contains dichlor which will raise CYA noticeably.

Right now, the water is just cloudy so I may have killed the algae but not sure.

Recommend running an Overnight FC Loss Test. Turn SWG off during this test.

My plan of attack, just want to confirm this sounds right:
Get the FC using liquid bleach to 28 and maintain for the day. Check the next day for FC drop and continue shocking until that doesn't drop more than 1 ppm.

Given a CYA of 60 ppm, the SLAM FC target is 24 ppm, per the Chlorine CYA Chart. However, I would test CYA again if you added the powdered shock after you performed the test results you posted above. I would test FC a few times a day during the SLAM process as testing once a day is not sufficient while SLAMming. Use liquid bleach for the chlorine source as you have planned.

 

[Bigsteveg]

I have not slammed the pool yet, was going to this evening. I checked the free chlorine at lunch, it went up. Not sure how possible that is, I took two tests this morning both were 15 FC. At lunch, I got 15.5 and 16.5. I wonder if it's possible that the pool shock is still being stirred up? I put it in around 6pm and the pump ran for about 4 hours.

Right now the vacuum cleaner and pump/filter are running, Aquapure is at 0% since yesterday evening when I added shock. If I wait and perform the OCLT, if it doesn't drop should I still shock it? The pool water has a slight green tint to it. It's raining and cold but I would still expect the FC to drop not go up.

 

[duraleigh]

Sometimes newbies don't carry the FC test to it's absolute endpoint. You continue to add drops of R-0871 reagent until the very last drop you add results in NO further color change...nada.

Subtract that drop from your count and the result is your FC.

That may account for your perceived increase in FC.

Do you have undissolved powdered chlorine on your pool floor? That's a no-no. brush it around until it's gone.

 

[Bigsteveg]

Well, the weather has been good for pool shocking! This morning it was 51 outside so the kids have not bugged me about swimming. I started shocking Monday at 6pm, first night OCLT dropped 2.5ppm and last night 1.5ppm, I'm hoping tonight it holds. Water is slowly getting clearer, the pump turned off last night on me so I lost some ground there but the pool vac and pump will run all day today.

 

[Richard320]

Well, the weather has been good for pool shocking! This morning it was 51 outside so the kids have not bugged me about swimming. I started shocking Monday at 6pm, first night OCLT dropped 2.5ppm and last night 1.5ppm, I'm hoping tonight it holds. Water is slowly getting clearer, the pump turned off last night on me so I lost some ground there but the pool vac and pump will run all day today.

I wouldn't even worry about the overnight loss until the hardest part of the SLAM is done - the water is clear.

That, ultimately, is the goal, is it not? Clear, sparkling water. Nobody is impressed with your CYA levels - they're impressed by sparkly water.

 

[linen]

Just to confirm, make sure when doing the OCLT that the swg is off.