I'm SLAMMING, Day 4, some questions

[survivalcar]

I learned about SLAMing here because my CC level was high, there was 0 free chlorine and the pool wouldn't hold chlorine no matter how much I added. We opened the pool a couple weeks ago and it was green and you couldn't even see to the bottom in the shallow end. In previous years I had been able to vacuum (on WASTE) a lot of the sludge out of the pool and just keep the chlorine high enough and refill from our well, which first goes through a water softener because there are insane levels of iron in the water here. After a while it would get clear, with a little TLC and vacuuming.

But this year it didn't hold the chlorine and the water was very cloudy even after all the green was gone (I assume the local guys who opened the pool hit it with some shock and algaecide - I wasn't here when they did it). The CYA reading was low so the first thing I did was add CYA. It now reads within the normal range.

On the 4th day of the SLAM, during which I've vacuumed and brushed at least once a day, and I keep backwashing and rinsing, like 3 or 4 times a day, I can finally see the bottom drain in the deep end, which is about 10 feet down. The water is still cloudy but it looks better every day. I have a good test kit as well as the strips (I know they're not as accurate but measuring the FC properly with the kit would take over 100 drops when the FC is over 20 - correct me please if my math is wrong).

I used the chart to determine the strength of the SLAM and as of now, everything is in pretty normal shape except for the chlorine levels.

So, since it's still cloudy, some questions:

1. Is it normal for the SLAM to take this long? It really didn't eat a lot of the shock and the FC only seems to dip a little below 20 after maybe 12 hours. Honestly those strips are pretty hard to read so maybe it's not really dropping that much at all.

2. I'm not sure if it's just the cloudiness of the water but there seems to be some almost-uniform dark smudge across the bottom and sides. It seems more prevalent in the deep end which makes me think it may be an optical illusion, since I'm looking through a lot more cloudy water than the shallow end. But is it possible that there's some algae growing that won't let go of the surface even when I'm vacuuming and brushing it every day? If so, can I add some algaecide or will that screw up the SLAM and/or mess up something else? Or is it more likely that it isn't algae and I'm just seeing things?

3. Before I slammed it, I threw in a bunch of non-chlorine shock, on the advice of the local pool guy. Didn't seem to do anything, but I've also got a big tub of Cal Hypo here and I've been throwing that in the pool as well. Should I be doing that?

Numbers:

Hardness: <50
Total Chlorine: >10
FC: >20
pH: 7.4
TAC: 100
CYA: 60

Thanks in advance for your help,

Chris

 

[kellyfair]

For the FAS-DPD test, fill to 10 ml line. That way if you use 30 drops, you divide by 2 and your FC is 15. You have to know your target FC for your SLAM... test strips won’t cut it.

With CYA of 60, your SLAM FC target is 24. You need to test every couple of hours and raise FC to 24 as often as you can. This will make your SLAM go faster.

- - - Updated - - -

Also, quit throwing stuff in! Use only liquid chlorine (plain bleach).

 

[survivalcar]

Yeah, I know the FC goal. Still that's 48 drops each time I measure it. I'm gonna run out! Maybe I should have waited to SLAM the pool until I had bought a giant bottle of the stuff. I figured with the strips at least I'm probably way higher than i need to be, since I measured out the amount of shock according to the table.

I guess I'll try to find a store to buy some more shock and drops tomorrow

Thank you. I'll stop throwing other stuff in there.

Chris

For the FAS-DPD test, fill to 10 ml line. That way if you use 30 drops, you divide by 2 and your FC is 15. You have to know your target FC for your SLAM... test strips won’t cut it.

With CYA of 60, your SLAM FC target is 24. You need to test every couple of hours and raise FC to 24 as often as you can. This will make your SLAM go faster.

- - - Updated - - -

Also, quit throwing stuff in! Use only liquid chlorine (plain bleach).

 

[kellyfair]

Do yourself a favor and check out tftestkits.net. You can get a kit that has enough reagents to get you through a SLAM and still have plenty left over.

 

[survivalcar]

Thanks. Another question though! I did just re-test with the drops, and while adding/counting the agent, there's a point at which the water becomes clear, and then about 20 or 30 seconds later it starts getting pink again. Not fully pink, just taking on a pink tint. Which is the more accurate reading? When it turns clear the first time or, as in this case, it turned pink after 30 seconds and then required another 4 or 5 drops to make it clear again?

Do yourself a favor and check out tftestkits.net. You can get a kit that has enough reagents to get you through a SLAM and still have plenty left over.

 

[kellyfair]

First time. It goes pink again if you leave it sitting.