Algae Continues to Come Back on Sides of Pool...what am I doing wrong?

[Beastmode45]

Hi -

I’m new to TFP, but have bought a Taylor K-2006C and have been testing daily. The balance looks good...here are my levels:

FC = 5
CC = 0
PH = 7.4
TA = 110
CYA = 40-50 (I believe it’s at about the 45 mark)
(My pool is ~22K gallons, chlorine pool - I don’t have a SWCG)

My problem is twofold.
1. I have to keep brushing the sides in a number of recurring spots because I see green algae forming.
2. Also, my FC levels are NOT changing much. They were at 6 when I left out of town Wednesday morning, and by Sunday morning (4+ days) it was at 5 (and it’s been in the 90’s here in SoCal). I would have expected it to be close to 0-1 when I returned after 5 hot days, and it hardly moved. Maybe this is related to my issue #1?

When I brush the algae, it comes off and turns into a cloud of green dust into the water.

I thought about SLAMing the pool (bringing FC up to 18 per the Chrlorine/CYA table). But when I read the post on getting rid of Algae and SLAMing, it seems like I should expect that my FC is being used rapidly first. But as mentioned earlier, my FC is barely moving so I’m concerned that if I bring up the FC to higher levels, it may not go down as fast as expected. Until I understand the FC issue, I don’t want to mess things up further. Is it possible that my CYA is wrong? I’m following the instructions on the Taylor K-2006c until I don’t see the dot.

Any guidance would be helpful.

Bryan

 

[mknauss]

Welcome to the forum!
Do you have pucks/tablets in the pool?

You do need to follow the SLAM Process

I suggest you read ABC's of Pool Water Chemistry.

 

[mknauss]

When you do the CYA test, try this next time.

Once you have your solution ready, back to the sun, etc. Fill the vial to a line, say 80, lower the vial to your waist level and glance for the dot, you see it, add solution to the 70 line, glance, see it, repeat until you no longer see it with a glance. Then use the CYA value one step above the line you read. So if you stopped at 50, use 60 ppm CYA.

The vial is in logarithmic scale. So it is not viable to interpolate between the lines. Just use the whole numbers, such as 50, 40, 30, ....

 

[Beastmode45]

Welcome to the forum!
Do you have pucks/tablets in the pool?

You do need to follow the SLAM Process

I suggest you read ABC's of Pool Water Chemistry.

Hi.
I don’t have pucks in the pool as I used to have high CYA (90+) and did a 50% water exchange a couple of weeks ago to get it to normal levels. So I’ve been keeping the stabilizer out of the pool so that the FC would work. So even though FC is going down slow, I should still SLAM to kill the algae? I will do that.

I have read the ABC’s. It’s what has gotten me to the better place to date. I just figured my FC would decline faster. I’m going to do the over night test to see how much I lose overnight and start the process.

Thanks

 

[mknauss]

It would be odd to have 0 FC loss over several days unless the pool is covered. I assume you are using your FAS-DPD test for your FC testing.

 

[JamesW]

Note that fc loss doesn't always correspond to algae or lack of algae.

Some algae is less reactive than other types.

If you have algae, you're not maintaining the fc high enough.

If you see algae, you should always go to SLAM level right away.

 

[Beastmode45]

It would be odd to have 0 FC loss over several days unless the pool is covered. I assume you are using your FAS-DPD test for your FC testing.

I just realized my mistake. I must still be hungover from vacation. I filled to the 10ml in my FAS-DPD kit and it took 5 drops. Which is “2.5” ppm - not 5 ppm. It’s only 0.5 ppm per drop. Duh. Sorry.

So I went from 6.4 to 2.5 in 4 days. That seems more correct.
So I will definitely do the SLAM as prescribed and see what happens.

Sorry all!!

 

[Beastmode45]

Note that fc loss doesn't always correspond to algae or lack of algae.

Some algae is less reactive than other types.

If you have algae, you're not maintaining the fc high enough.

If you see algae, you should always go to SLAM level right away.

Thanks! That is good to know and I will do the SLAM and see how things go.