Algae not going away after 1 week SLAM

[darthv]

I had a bad algae problem in 30k plaster pool. Water was starting to get green but mostly on floor and sides.

Drained half my pool, and starting numbers after refill
ph 7.5
cya 40
calcium 750

I slammed and got FC to 16 and keeping there by twice a day Check along with one backwash and one filter clean

after two days with initial scrubbing pool looked like it was getting better.

But since then then there is still about 10% of the original algae on the walls and floor in spots and streaks. I’ve tried scrubbing down with a steel brush but does not think it helps. The FC checks now show very little 12 hr loss. In 24 hrs goes from 16 down to 12. CC are still positive but improving

wouldn’t a scrub expose this algae to the chlorine and end up all dead in 1-2 days?

’ive also been running my m400 pool robot to see if a little bit more scrubbing would help but to no avail.

Filter has been run 24/7

thanka for your help. BTW increased FC to 20 thinking I may have gotten CYA reading wrong

I use tf-100 kit

 

[YippeeSkippy]

Darthv, if you were only dosing twice a day that will extend the time for a SLAM. You're using liquid chlorine to add FC...right? I can't quite understand how your CH is 750ppm already since you just drained 1/2 the water and refilled.

What are you numbers now-
FC
CC
pH
TA
CH
CYA

Maddie

 

[tim5055]

The minimum we recommend testing and adding chlorine during a SLAM is 3times a day. But, with that being said the harder you hit it in the beginning the better. I like to see a SLAM start on someone’s “weekend” so they can have two solid days of testing and adding chlorine back to SLAM level every hour or two.

 

[darthv]

Well now the FC doesn’t change when I check every 12 hrs but changes by 24hrs and it’s been that way for about 2 days.

I dont see a huge huge change in the remaining algae in the corners and sides.

My question is, should it be this hard to scrub off every little bit or should it be quite easy after shock level for a few days.

Will ll it slowly dissipate over the next few weeks?

Even direct scrubbing doesn’t seem to be changing the green.

I’ll have to do a complete check again but I didn’t think CH and TA mattered that much for a slam. My water is super hard in Southern california

 

[mknauss]

Are you sure the remaining is algae? If being kept at shock level for this long it should not be green and it should come off the walls unless your plaster is very rough.

Any copper algaecides or other potions used in this pool?

A signature would be nice to provide us lots of useful information - see Pool School - Getting Started

Take care.

- - - Updated - - -

CH and TA do not have a direct effect on FC. The TA can drive up pH which makes FC a bit less effective.

The question on the CH was how did you still have 750 ppm CH after draining. Unless you started at 1200 ppm plus.

You are using liquid chlorine for this SLAM, correct?

 

[darthv]

I am using 10% liquid chlorine from Home Depot.

I wasnt too surprised by the CH since at one point it was over a thousand. I can check my fill water to Check.

Maybe I just need to keep it going longer and at shock level 20 for CYA 50.

I just checked my CYA and it’s closer to 50 than 40 now. I’ll update if still no good

my pool and spa have a lot of right angles that i matter how much I scrub I can never quite get right to the corners and this I was hoping algae would just slowly die without too much scrubbing. Thanks

collin

 

[mknauss]

Are you testing the FC about 30 minutes after you add chlorine? Most of the Home Depot LC is pretty old this time of year. Be sure to check the Julian date on the box. Needs be after 17300 -- or the 300th day of 2017.

Walmart bleach is the freshest, by far.

Take care.

 

[darthv]

This SLAM is the most frustrating ever.

I have been at it for 2 weeks. This past week FC kept at 20 continuously. CC at a minimal 0.5. CYA between 40 and 50

The green on on the walls has not come off at all and scrubbing with a wire brush doesn’t help.

I have made no progress in the past week despite using a higher FC target

Could these have stained the plaster somehow and not dead algae?

 

[YippeeSkippy]

Hmmmmmm..... what else have you put in the pool? Any cheap algaecides? Copper or other metals?

Maddie

 

[darthv]

I haven’t put anything else in at all except for liquid bleach. Maybe I’m reading the CYA wrong and mine is much higher? Maybe my shock level should be higher? I did recheck and I think I got it right.

Can algae tar left on the walls for a long time dye the plaster permanently?

there are other stains on the walls which I thought was metal but those are old. These have come out when my pump stopped working briefly a few weeks ago

collin


QUOTE=YippeeSkippy;1367203]Hmmmmmm..... what else have you put in the pool? Any cheap algaecides? Copper or other metals?

Maddie [/QUOTE]

- - - Updated - - -

I haven’t put anything else in at all except for liquid bleach. Maybe I’m reading the CYA wrong and mine is much higher? Maybe my shock level should be higher? I did recheck and I think I got it right.

Can algae tar left on the walls for a long time dye the plaster permanently?

there are other stains on the walls which I thought was metal but those are old. These have come out when my pump stopped working briefly a few weeks ago

collin


QUOTE=YippeeSkippy;1367203]Hmmmmmm..... what else have you put in the pool? Any cheap algaecides? Copper or other metals?

Maddie [/QUOTE]

 

[mdogan]

If I'm not wrong you have to started slam PH 7.2
in first post it was 7.5
I'm not sure if this impact or no.

 

[tim5055]

If I'm not wrong you have to started slam PH 7.2
in first post it was 7.5
I'm not sure if this impact or no.

The pH will not affect the SLAM Process. We recommend starting at 7.2 because most pools have a rise in pH over time. As the pH test does not read properly with FC above 10 (where most SLAMs are) this gives you a longer pH rise before any issues may arise.