CC level during a SLAM

[wags22]

I'm into the 2nd day of doing a SLAM to eliminate what I believe is algae (see pics).
When I started my CYA was 60, PH around 7.6.
The pool was clear when I started, just had some patches of algae. The patch in the spa was algae as it was actually green, the other patches I'm not so sure.
According to the pool math calculator I need my FC level to be at 24. My last test was around 17. My overnight drop was about 8.
My question is that everytime I've done the FAS-DPD test and then add the drops for CC, it does not turn pink again. Is this normal? From what I understand about the process, it should immediately turn pink with the 5 drops and then 1 drop of R-0871 should turn it clear again to reach the .5 goal?

 

[magiteck]

I'm into the 2nd day of doing a SLAM to eliminate what I believe is algae (see pics).
When I started my CYA was 60, PH around 7.6.
The pool was clear when I started, just had some patches of algae. The patch in the spa was algae as it was actually green, the other patches I'm not so sure.
According to the pool math calculator I need my FC level to be at 24. My last test was around 17. My overnight drop was about 8.
My question is that everytime I've done the FAS-DPD test and then add the drops for CC, it does not turn pink again. Is this normal? From what I understand about the process, it should immediately turn pink with the 5 drops and then 1 drop of R-0871 should turn it clear again to reach the .5 goal?

If it doesn’t turn pink again, that means your CC is 0. That’s a good thing; it means your FC is high enough that it’s oxidizing the CCs being created and not allowing it to accumulate. Keep slamming until the water is clear and you pass the OCLT and you’ll be golden.

 

[wags22]

One more question. I'm using the pool math app on phone to calculate how much chlorine I need to add. If it tells me to add 3/4 of a gallon, does it hurt anything if I just add the entire gallon?

 

[wireform]

Wags,
Hi and welcome. Firstly just as a side note for a future slam (hopefully never) your PH needs to be at the 7.2 not the 7.6 and once the FC is above 10 then your PH test is unattainable.
Chlorine above the cya ratio level for slam is not going to do anything besides waste and bleaching the liner then can occur. Once you have a slam going just work with the FC and forget the CC. When you're getting ready for the OCLT then you can check it as most likely it'll be 0-.5 as the slam does exactly that.

 

[wags22]

I still have some residual algae on the bottom of the pool and the seat in the spa. It is black/dark green in color. I've been slamming it for almost 2 weeks now and it still isn't going away. However, it is difficult to keep it at the SLAM level (12) but it hasn't fallen any lower than 7. My lowest OCLT was 1.5 the night before last and last night I got in and hand scrubbed the algae (some of it is at the base of the step which is hard to reach with a pool brush.

My question is: Am I missing something or doing something wrong that it has taken this long and this algae still isn't going away?

 

[mknauss]

What test kit are you using? Please add that to your signature. Can you post a full set of test results? You have not saved any test results to your Poolmath log.

 

[wags22]

I'm using the FAS-DPD test (had to get another bottle of drops just this week). As I mentioned, I've been doing the SLAM for almost 2 weeks so I haven't taken any readings of anything except FC. When I started CYA was at 30 and PH was at 7.2.
I work away from home during the week so my wife has been doing the testing and then passing me the drop count to use the pool math calculator on my phone and tell her how much liquid chlorine (10%) to add. We don't have an exact history but FC has ranged from 7 to 12, with the lower readings occurring during the day due to sun loss.
I'll start logging the FC to the app.

 

[mknauss]

You tested your own CYA level? The test kit name/brand/model in your signature really helps us.

 

[wags22]

I took your advice from earlier in this thread months ago and got the TF-100 test kit. I did have one of the Walmart HTH kits that also had the CYA test.

 

[mknauss]

Great. Thank you.

OK -- so when a SLAM drags on, it is normally due to not keeping the FC at SLAM level, not brushing, or large amounts of organic material in the pool. Are you sure the black/dark green is algae? Does it brush off?

 

[duraleigh]

It is black/dark green in color. I've been slamming it for almost 2 weeks now and it still isn't going away.

If it's still there, put a wire brush on it and brush it loose. Keep your FC at SLAM value until your pool surfaces and water are all crystal clear.

 

[wags22]

Yes, it brushes off, but only in little bits. It is slimy/smooth to the touch. We've been brushing at least twice daily and at most there has only been a leaf or two in the pool at any given time.
Does the amount the pool app gives as the goal account for immediate dropping? How often should we be testing to maintain the level?

 

[wags22]

My fear with using the wire brush is that it will damage the pebble-tec. It it unfounded?

 

[mknauss]

For a SLAM process to work, testing FC and adding liquid chlorine needs to be done 3-4 times per day. And brushing that area daily. As Dave said, take a brush to it. Is it embedded in the pebble-tec?

 

[wags22]

Yes, it is embedded.

 

[mknauss]

Black algae is a different animal. But you still are having too much drop in a OCLT right?

 

[duraleigh]

That's why they make wire brushes. Your finish will be unharmed. It sure sounds like you have black algae and it doesn't come loose with a dainty pat on the head. Keep your FC up until all traces of any algae are gone.

A Pic of the algae would likely confirm that we suspect black algae.