Am I SLAMing right?

[chemmy]

18' x 48" above ground Intex/Bestway pool. I have a thru the wall skimmer and a 2500 gph Intex pump with cartridge filters. It was hard to find chlorine for a while here and my pool went this deep green shade I've never seen. It was weird and the pH was off the test chart which was also weird. It took 5 lbs of powdered acid to being it down to 7.2 (and I've never ever had to use acid before so I wondered if someone threw something in?)

Anyway, I found 56% calhypo powder and started using it to SLAM. The deep green went away but it's been over a week now and it hasn't changed color at all and there's bubbles on the surface. I noticed that the calhypo (HTH brand) would turn from white to blue when I put it in the pool but I wasn't sure if it mattered. I've never used it. I finally got some 10% chlorine and I am continuing to SLAM but the color isn't changing and it's kind of cloudy. I am sweeping it multiple times daily and there's nothing floating to the top or anything. Also cleaning the cartridge daily. I need some reassurances or help.

pH 7.2
TA 100
CYA 50
FC 20 (it was dropping to 14ish and I was maintaining it at 20 and it only dropped to 19 overnight, so that's good?)
CC 1
CH 70

I've always been able to resolve a green pool and this is so frustrating. I keep cleaning the filter expecting it to be brown with dead algae but it's usually hardly dirty. I use the TFP test kit if that matters.

 

[AK-]

Did you subtract your CC from the TC to get the FC?

A CC of 1 means there is something consuming your FC.

 

[chemmy]

Did you subtract your CC from the TC to get the FC?

A CC of 1 means there is something consuming your FC.

The FC number I listed is what the test kit told me it was without any math involved. Am I not calculating right?

I know the CC means something is consuming it but I've never had it take so long to achieve results.

 

[AK-]

If I’m not mistaken the number of R-0871 drops (multiplied by 0.5) will give you TC. If you have CC then you need to calculate the FC (FC = TC - CC).

That means you lost 2ppm of FC overnight.

The SLAM exit criteria are:
- clear water
- CC < .5
- OCLT <= 1

Seems you did not met any of them yet.

 

[chemmy]

The number of R-0871 drops (multiplied by 0.5) will give you TC. If you have CC then you need to calculate the FC (FC = TC - CC).

That means you lost 2ppm of FC overnight.

The SLAM exit criteria are:
- clear water
- CC < .5
- OCLT <= 1

Seems you did not met any of them yet.

Thanks for the reassurance.

 

[AK-]

Two quick questions…

1 - for how long are you SLAMming?

2 - What is your water source? Are you sure you don’t have metals in the water?

 

[chemmy]

Two quick questions…

1 - for how long are you SLAMming?

2 - What is your water source? Are you sure you don’t have metals in the water?

I've been going for like a week now. Maybe 10 days? Summers kinda blend all together for me (teacher). It's city water. Shouldn't be metals?

 

[AK-]

Some metals can react with chlorine and make the water green. Did you add anything else to the pool? Algeacide often contains copper.

 

[chemmy]

I don't use algaecide since I've never needed it with TFP. However, the calhypo I used is HTH Ultimate Mineral Brilliance Chlorinating Granules. Never used it before but it just says active ingredient is calhypo 56%.

 

[AK-]

From what I could find HTH Ultimate Mineral Brilliance Chlorinating Granules has no copper or iron (both could somewhat turn water green). It does lists aluminum sulfate (FLOC) that can turn water cloudy and magnesium something

Bubbling on surface, green water and CC are consistent with organic matter being oxidized. There are plenty of reports of SLAM lasting two weeks, so I wouldn’t give up now.

I’d keep SLAMming for few more days and watching CC and OCLT closely. If those two criteria pass, but water still cloudy/green then it is possible something other than algae is causing it.

 

[AK-]

Hello @chemmy, did your pool clear up?