Newbie SLAM questions

[JaySee]

Your FC is falling much too low. We know it should be maintained at 16 during the SLAM Process, but it's never gotten close. The chlorine has yet to overtake the aggressive organics. Once you can find a new supply of chlorine, add the 3 gallons or so required to get to 16, then test again in about 20-30 minutes. Test more frequently at first until you see the FC hold.

Thanks Texas and Mike,

Could there be another source of algae that I'm not seeing? There's only one light, 3 rungs on a ladder, and 4 stairs that are clean apart from some silt that I brush away before vacuuming. On the next chlorine dump should i pour it directly over these areas to target them? (light, ladder, stairs). I've been typically pouring the chlorine near the return jets.

Incredibly frustrating that I can't "see" where the issue lies.

I'm going to buy another 50L of chlorine today, but tomorrow is Canada Day -- all retail is closed. In case I do run out, would you recommend using "HTH EXTREME SUPER SHOCK" or "IPG ZAP"? There's bags left over from the previous owner but I haven't touched them. (Not sure what exactly is in IPG ZAP as it's non-chlorine oxydizer and there's no ingredients listed on the package or their site).

Also any opinions on using a clarifier to help filter small particles in stubborn cases like this, as recommended by the pool tech?

Thanks!

 

[Mike1162]

Don't use any floc or clarifiers. Did you use 50L yesterday? If so you might want to get 100L today to get you through the holiday. You'll need it eventually so it won't go to waste.

 

[Mike1162]

When was the last time the filter was backwashed? Do you know the clean & dirty pressure on the filter?
It's not just algae that consumes chlorine, the slam process will work if you stay with it.

 

[JaySee]

When was the last time the filter was backwashed? Do you know the clean & dirty pressure on the filter?
It's not just algae that consumes chlorine, the slam process will work if you stay with it.

Yesterday I used 25 Litres. (2 x 10, 1 x 5 chlorine dumps)

Just tested 2 hours after my last SLAM-- FC: 8.5, CC: 1.
Once I get more chlorine on my lunch break I'll drop another 5L in there as per Pool Math.

Questions/Observations:

- The filter was backwashed about a week ago. The clean pressure is just above 15-- right now the pressure is sitting just under 20.
Do you recommend doing a full backwash/rinse once more before continuing with the SLAM?

- Did another algae hunt and found that there's a bit of green INSIDE the pool light. under the plastic lens. Are these lights straightforward to disassemble/clean while still submerged without risk of shock or ruining the light or electrical?

- I can't imagine not having a pool robot and still being able to sustain a full time job. Go robot, go!

 

[Texas Splash]

We recommend backwashing when your filter pressure increases by about 25%. So you are probably close. As for the light, if you have a standard large light in the deep end, it's probably held in place by a retaining ring that has one screw. If so, you can remove the light by taking out that screw, remove the ring, and pull out the light placing it on the decking. But FIRST - turn OFF power to the light. Power off first, then remove the light.

 

[JaySee]

We recommend backwashing when your filter pressure increases by about 25%. So you are probably close. As for the light, if you have a standard large light in the deep end, it's probably held in place by a retaining ring that has one screw. If so, you can remove the light by taking out that screw, remove the ring, and pull out the light placing it on the decking. But FIRST - turn OFF power to the light. Power off first, then remove the light.

Oh boy.

The light is one of those "screw out" Aqualamp style. Took it out easily and *poof* a cloud of black stuff came out. The cord feels really slimy. On my next break I'm going to scrub hole, test the water and nuke it with chlorine pouring it right at the light cover. I'll keep the light out, take it apart and scrub every part inside later. The quest continues!

 

[Texas Splash]

Took it out easily and *poof* a cloud of black stuff came out.

Great catch! Yes, clean it out but still leave the light out so that the chlorine can continue to penetrate the niche really well. That should help tremendously.

 

[JaySee]

Scrubbed out the light alcove ! Skimmed as much as possible by hand/net. There were chunks of what looked like white vinyl in there.

Did a new test 9 hours after my last chlorine dump:

FC: 3.5 (down from 8.5 7 hrs ago when i didn't have any chlorine left)
CC: 0.5 -- the fact that the CC is consistently going down is a good sign?

As per pool math, dumped another 7.5L of chlorine right above the light alcove. In about 2 hours after the chlorine has a chance to disperse I'll send out the pool 'bot to vacuum the gross stuff that came from the light.

 

[Texas Splash]

The CC level fluctuates and isn't always directly tied to algae removal, so don't place too much focus on that right now. Now that you have the niche exposed, you can just add chlorine like normal at the return jets and let it assimilate like normal. FC (SLAM level) consistency is the important thing right now.

 

[JaySee]

Did a test 6.5 hours after my last chlorine drop:
FC : 9
CC : 0.5

Adding another +5 L of chlorine as per pool math -- should I do a last test in 2 hours tonight and then see if it passes the OCLT tomorrow morning regardless of the final FC #, or OCLT ONLY if it hits the target SLAM FC (16) tonight?

Thanks!

 

[JaySee]

Did a test 6.5 hours after my last chlorine drop:
FC : 9
CC : 0.5

Adding another +5 L of chlorine as per pool math -- should I do a last test in 2 hours tonight and then see if it passes the OCLT tomorrow morning regardless of the final FC #, or OCLT ONLY if it hits the target SLAM FC (16) tonight?

Thanks!

I'll answer my own question:

Will do a final test in about 2 hours, and then again before sunrise. If there's a 1ppm loss or less, the water is clear, and my CC is 0.5 or lower-- the SLAM is complete!. Then it's time to check and balance PH.

 

[Mike1162]

Results . . .

 

[JaySee]

Last night-- 2 hours after the last chlorine drop:
FC: 15.5
CC: 0.5

This morning at 6 AM:

FC: 13 (down 2.5 from last night)
CC: 0.5
Water was absolutely crystal clear.

6AM wasn't quite early enough as the sun was already rising, so not sure if the FC went down because of UV or because of algae etc. But 2 out of 3 OCLT criteria is not good enough.

Vacuumed, went for a first swim (tested PH = 7.6 beforehand) , and then it started raining cats and dogs. Once the sky clears I'm going to test again, and continue the SLAM again and try the OCLT again tonight.

While in the pool I scrubbed the skimmer hole and light alcove one more time. Hopefully that's everything and the FC holds tonight!

 

[Mike1162]

I'd have been surprised if you passed the OCLT this morning. My bet is you'll be slamming for a couple more days.

 

[JaySee]

After the rain the tests were--
FC : 9.5
CC: 0.5

Here's an interesting wrinkle: the CYA dropped to under 30 (could still see the black dot oh so faintly at 30)

I'm going to do a SLAM based on a CYA of 30 (roughly 2 litres), but should I look at raising my CYA back to 30/40 at this point?

And when doing the CYA black dot test, should the dot be 100% 'gone' if i'm staring right at it? At a 'glance' the dot wouldn't be noticeable but I've staring right down the tube and making sure there's not even a ghost of a dot in sight.

 

[wireform]

At a 'glance' the dot wouldn't be noticeable

That's what you look for while testing CYA, not staring.

 

[JaySee]

That's what you look for while testing CYA, not staring.

Whew, perfect. Thanks!