SLAM for 3 days, no results?

[ioinva]

I was waiting for temperatures to drop enough to close our small 5000G pool for the winter. Pump running on schedule, but the chlorine tabs ran out and leaves from a storm filled the bottom, despite the solar cover. Now the pool is green.

After vacuuming and brushing with a soft nylon bristle brush, I added chlorine (dichlor) to SLAM level (12) and waited for magic. 3 nights into the process, the water is slightly less cloudy, but still green. Puzzlingly, the Free Chlorine is barely changed and there is hardly any Combined chlorine registering on the DPD test kit. I used fresh testing supplies, last year's shock. Water temperature is 68F, outside temperature is 50 - 65F.

Does that sound right? I was expecting to see the chlorine depleted faster, and the combine chlorine all the way up. OR, if my dichlor had lost its efficiency by sitting on the shelf (never needed to SLAM last year or this year), then the chlorine should not register, right?

Is it the low temperature that slows the chlorine efficiency, or is the chlorine too old? Why is my combined chlorine so low yet the pool still green and free chlorine high?

Volume: 5000G, Temp: 68F
Free Chlorine: 12.00
Combined Chlorine: faint pink easy neutralized by 1 drop of reagent (=.5)
PH: 7.4
TA: 90
CYA: 40
Light colored solar cover on at all times. Vacuum runs 1h/day. Pump runs 24h/day (vacuum is supply side), .3HP / 2100gpm with an 18" Hayward filter filled with filter balls. Return is a through-the-wall Hayward skimmer. An additional 1800gpm cartrige filter runs the solar heater and stayed on to help with this job.

Hot and humid VA summers with daily storms have never given me problems after we installed the larger pumo and Hayward filter and skimmer. Literally never had to shock this pool after that miserable first year..

 

[Bperry]

Some advice. For a CYA of 40, the SLAM level is 16ppm. Using dichlor for that process isn’t a great idea as it also raises the CYA at the same time. Switch to liquid shock to avoid that.

It’ll take longer using below SLAM level and 3 days is a very short SLAM so you just need to keep at it longer. It may take a week or two depending on how diligent you can be with maintaining the FC each day.

 

[YippeeSkippy]

You can NOT SLAM a pool with Dichlor.... it requires you to use Liquid Chlorine which immediately raises the FC level of the pool and fights the algae...then gets used up and requires Re-dosing to SLAM level. This is something you should do at least 3x day, but more is better.

Maddie

 

[Mdragger88]

Using the dichlor is just raising the cya which in turn increases the required slam level.
Liquid chlorine is the answer,
Testing & replenishing slam level multiple times per day FC/CYA Levels as mentioned above.

For a successful SLAM Process
you need to continue to MAINTAIN Slam level fc for your cya (which is 16ppm) until you meet ALL 3 end of slam criteria-

You are done when:

CC is 0.5 or lower;
You pass an Overnight Chlorine Loss Test
AND
the water is clear.
(Crystal Clear w/no algae dead or alive)

*Check & scrub every nook & cranny where algae may hide (light niches, steps, drain covers, ladder handrails, skimmer throats/weirs, etc.)
*Run slam level water through all water features & lines for at least a couple hours a day during the SLAM Process.
*Brush & or vac daily (this breaks up biofilms that algae uses to protect itself from chlorine)
*Backwash/clean filter when pressure rises 25%over clean pressure.

Don’t be discouraged, Rome wasn’t built in a day, just keep at it

 

[gingrbredman]

Already great advice on the problem and the solutions!

Question...

SLAM for 3 days, no results?​

Answer....

You can NOT SLAM a pool with Dichlor.... it requires you to use Liquid Chlorine

Using the dichlor is just raising the cya which in turn increases the required slam level.

The SLAM page does a really good job of explaining the process, and the key words here are...
You cannot do this overnight…it often takes several days to see it completed…no shortcuts.

Why is my combined chlorine so low yet the pool still green and free chlorine high?

Sometimes, with a green or cloudy pool, you will not always see a high CC result. Anything above .5 usually indicates that something in your water is being consumed by the chlorine, but I have seen many a green or cloudy pool with a CC of .5.

The path forward is a SLAM, following the SLAM protocols, which included liquid chlorine.

 

[ioinva]

Switching to liquid chlorine tonight -- i was under the weather and nothing really happened yesterday. I might end up breaking down and emptying the pool this winter rather than add tons of chemicals, seeing how my CYA is already on the high side and will stay high over the winter. The plan is to add a SWG system when I reopen, to avoid the CYA issue in the future, so learning more about that before deciding what to do.

 

[Bperry]

Switching to liquid chlorine tonight -- i was under the weather and nothing really happened yesterday. I might end up breaking down and emptying the pool this winter rather than add tons of chemicals, seeing how my CYA is already on the high side and will stay high over the winter. The plan is to add a SWG system when I reopen, to avoid the CYA issue in the future, so learning more about that before deciding what to do.

Is your CYA only 40ppm? That’s about the right level. No need to lower it.

 

[ioinva]

Until this adventure, I have not really had to shock, so the single source of CYA has been the puck.

trying to fix the green water using dichlor completely backfired. I should have known better, but I was under the weather and figured this was going to be a quick fix. Instead, the CYA went up over the last week from 40ppm to 50ppm and now i'm at 55ppm -- after i emptied about 2" of water and let it replenish from the Ian remnant rain overnight... So now the SLAM level is 22m not 16... and of course after the rain, my chlorine dropped to 10. I'll add my gallon of 10% bleach overnight and put a dark cover tomorrow over it, but I really have the feeling that I'll need to drain, disinfect the walls, store the pool and restart in the spring, maybe with a SWG instead of pucks... Frustrating, as I already had 2 gallons of bleach on hand -- i was just feeling to sick to go find them and use them. Now i pay the price.

 

[Mdragger88]

Your cya counts as 60 as there really are no inbetweens with the cya test. You always round up if inbetween.
The slam process & subsequent fc maintenance thereafter is totally doable with a cya of 60.
Your SLAM Process fc level is 24. With a small temporary pool such as yours it can sometimes be simpler & more cost effective to drain, scrub & start over than to fight with trying to slam - especially if you generally take the pool down & store it for the winter anyway. The liquid chlorine you have purchased isn’t a waste. It is just concentrated bleach & can be used for a multitude of cleaning purposes including diluting it & scrubbing your pool. I think most here were under the impression that you were wanting to winterize your pool (aka - leave it up). Only you can decide how you want to proceed but the cya of 60 shouldn’t be the deciding factor.

 

[Bperry]

Your cya counts as 60 as there really are no inbetweens with the cya test. You always round up if inbetween.
The slam process & subsequent fc maintenance thereafter is totally doable with a cya of 60.
Your SLAM Process fc level is 24. With a small temporary pool such as yours it can sometimes be simpler & more cost effective to drain, scrub & start over than to fight with trying to slam - especially if you generally take the pool down & store it for the winter anyway. The liquid chlorine you have purchased isn’t a waste. It is just concentrated bleach & can be used for a multitude of cleaning purposes including diluting it & scrubbing your pool. I think most here were under the impression that you were wanting to winterize your pool (aka - leave it up). Only you can decide how you want to proceed but the cya of 60 shouldn’t be the deciding factor.

Yep. No need to drain if the cya is only 60.

 

[ioinva]

I've drained each year, but this was the year I was going to try to winterize... So I'll still give it a honest try with the SLAM process and try to keep it up.