FC keeps increasing?

[Beachkimball]

Hey everyone. I had an algae bloom last month, and I completed a SLAM about a week ago. Water was crystal clear, CC was 0, and OCLT was successful.

Since then, I've been trying to get my FC back down so I could get accurate pH readings and prep for hopefully warm weeks ahead, and everything was working fine, but today two things that have happened that I don't understand:

1. Throughout the SLAM, I had little green bits of algae (I think, little flower-shaped green slimy things like the flower on the cover of a box of Trix cereal) in my robot filter. They went away at the end of the SLAM, but then today they came back. There aren't a lot, maybe 5 or 6 in each filter, and the filter was slightly green.
2. This morning, somehow, the FC had actually increased from 9.5 to 13.5, and I can't figure out why! I don't have a chlorine generator, I have no chlorine puks in the pool, and haven't added any manually.

If anybody can help me understand these things, that would be appreciated! Pool is still blue and the CC is 0. Details below. Only thing that I can think of is that maybe the Sodium Thiosulfate hid the chlorine, but then it dissolved and the FC came back? Or the clarifier actually has chlorine in it? I have no idea, but thank you all in advance!

Brett

4/16 am: FC 20.5, CYA 50, CC 0.5, TA 70. To get FC down, I added 1.5 cup of Sodium Thiosulfate.
4/16 pm: FC 16.5, CC 0.5, pH 8 (I diluted the sample 1:1 with fresh water to get an accurate pH reading. Added 1.5 more cups Sodium Thiosulfate, then later 16 oz 31% muriatic acid. I know that's a lot of Sodium Thiosulfate, but my experience with it before is that it didn't work nearly as well as the bag said it should.)
4/16 pm: FC 15, CC 0, pH 7.6
4/17 am: FC 12.5, CC 0, pH 7.5 (this seemed like a big drop, but the prior reading was mid-afternoon)
4/17 pm: FC 11, CC 0.5, pH 7.2 (we had some acid rain that brought the pH down), CYA had risen to 70. Added 1.5 lbs pH up.
4/18 am: Added 4 oz clarifier (because I found the little green pieces in the robot and was hoping this would help the sand filter catch them)
4/18 pm: FC had risen to 13.5, CC 0, pH 7.5. - I tested the FC twice, both 25mL samples, using two different FAS-DPD powders and bottles of R0871 (thinking that maybe my first one had gone bad, I ran it again)

 

[Texas Splash]

Well, our weather has been uncharacteristically chilly and cloudy. My FC has increased a bit each day for the past few days. Just not enough heat/sun to use-up chlorine. That's a good thing for us. Now other than that, with no chlorine added, it could simply be a testing error or variance of some kind. It's easy to do. But rest assured the FC will fall. Starting tomorrow our weather is supposed to shoot back up considerably, so expect FC to drop as well.

About the flower things you are finding ........ any chance those are just flowers blooming from everything around us? Our Red Tips, Trees, and everything else around us is going nuts with white flowers blooming. Perhaps that's all it is? If you're not burning through FC in the next day or two, it may just be something seasonal. Do you use a skimmer sock in your poolside skimmer? However if in the next day or two you see green plumes of dust at the bottom of the pool, then it's time to think about algae again. Just something to watch.

 

[mariane]

I don't have an answer for why FC is going up but I do have a few questions.
Why are you trying to lower the FC if you are still seeing algae in the robot?
In Texas with the hot sun, why not just let the FC come down on it's own instead of using chemicals to lower it?
Are you vacuuming to waste to get rid of the algae?
Using clarifier will not work unless you let the pool sit for (I think) 24 hours, to wait for stuff to settle, then vacuum to waste. Is that what you have done?

 

[Beachkimball]

Thanks for the replies. I’m not sure if the green things in the robot are algae, or as the other poster said, just things falling off trees. But I’ve completed the slam and have passed the OCLT, combined chlorine and pool clarity tests, so I figured I was done.

I don’t have a vacuum, just the robot that I am using and then cleaning the filter after every session. But I have backwashed and the view tank runs clear. I’m brushing the walls and steps daily, and there’s no green at all.

I was trying to get the chlorine down because I was hoping that the kids can go in this week, but is it really bad to use chemicals to reduce it? Is that not advisable? I did notice there’s no calculation for it in the app...

Good point on the clarifier. I haven’t turned off the filter, but I’ll do that next time I use it.

Think I may need to SLAM again even though i passed the first one? I was hoping to avoid it so I don’t have to go out with my face mask and buy more bleach!

 

[Texas Splash]

If you passed all 3 SLAM criteria, you should be good. My water is about 70 degrees, still a bit chilly. But if your kids feel like going in, they can. As long as your FC does not go over 20 (your current SLAM level), it's all good. I missed the clarifier thing earlier. Definitely stay away from those products. Floc and clarifiers coagulate particles in the water. Seems like a good idea until it hits the sand and ruins it. Gets kind of gummy. So just stick to chlorine/regular bleach.

 

[Beachkimball]

If you passed all 3 SLAM criteria, you should be good. My water is about 70 degrees, still a bit chilly. But if your kids feel like going in, they can. As long as your FC does not go over 20 (your current SLAM level), it's all good. I missed the clarifier thing earlier. Definitely stay away from those products. Floc and clarifiers coagulate particles in the water. Seems like a good idea until it hits the sand and ruins it. Gets kind of gummy. So just stick to chlorine/regular bleach.

thanks. I appreciate the help. Will check FC again tomorrow!

 

[Beachkimball]

Hi all, wanted to provide some pictures and hopefully get another look. Water is still crystal clear (I threw a quarter in the 8' deep end, and you can tell heads/tails, but I couldn't get a good pic), FC is 11, still coming down CC is still zero, and did't do an OCLT last night, but will tonight. Meanwhile, here's what I'm seeing. Can't find any pictures of it online, but I have about 5 or 6 in my robot every time I use it. Like little dark green corn on the cobs. Is this algae, in which case I need to re-SLAM? Thanks so much!

 

[Texas Splash]

The water looks very nice to the naked eye, but I do not like the looks of that filter or what is on your finger. I would definitely start reading-up on the SLAM Process and do the Overnight Chlorine Loss Test as well. Some other things to consider if it's been a while:
- Removing the pool light to clean behind in the niche (if equipped); power off to the light
- Deep clean the sand

Not quite sure what those particle are. I don't recall getting those on my side of town. Almost look like parts of a rollie-pollie, but I haven't seem them out yet. Maybe just something from your trees?

 

[Beachkimball]

Thanks! I've owned the house for a year but have no idea what is inside the sand filter or when it was last looked at! I'm a little worried about trying to deep clean it on my own and potentially taking the filter out of commission for weeks by messing it up. Since you're in the area, do you have anybody you recommend that could help with that and maybe advise on whether the filter might need to be replaced? It is pretty old.

 

[Texas Splash]

Since you're in the area, do you have anybody you recommend that could help with that and maybe advise on whether the filter might need to be replaced? It is pretty old.

Unfortunately I don't. I know quite a few places are still on lock-down with the whole virus thing going on. So that may have to take a backseat for a while. But I do think it would be a good one on your "Post-COVID" to-do list. Ha.

You can read-up on it and watch a couple video in advance here: Deep Cleaning a Sand Filter

 

[Beachkimball]

Thanks, appreciate it! I'll check out the videos and do an OCLT tonight!

On the rollie-pollies, by the way: I have noticed a bunch in my yard already, and a few dead ones in the pool. You may be right that these are just the chlorinated remains of others that I found too late, but we will see!

 

[mariane]

I don’t have a vacuum, just the robot that I am using and then cleaning the filter after every session. But I have backwashed and the view tank runs clear. I’m brushing the walls and steps daily, and there’s no green at all.

I was trying to get the chlorine down because I was hoping that the kids can go in this week, but is it really bad to use chemicals to reduce it? Is that not advisable? I did notice there’s no calculation for it in the app...

Good point on the clarifier. I haven’t turned off the filter, but I’ll do that next time I use it.

Think I may need to SLAM again even though i passed the first one? I was hoping to avoid it so I don’t have to go out with my face mask and buy more bleach!

Isn't Texas Splash great? As all the mods too! He's got you covered.

I have my 2 cents to add:
I personally see no point in bringing down chlorine levels using chemicals unless you've slammed the pool and need to swim the next day, which rarely happens. It lowers on its own in a few days to a safe swimming level, esp in sunny Texas.

Good brushing! Backwash sometimes needs a little longer than "view tank runs clear". It's usually a couple minutes for it to be fully backwashed but others might have another opinion.

Deep cleaning the sand filter is very easy. If you watch the link Texas Splash attached, it will help. The only concern would be if you jam the garden hose down to the bottom and you crack a lateral (then you've got problems. Not all filters have laterals but most do.) You will see a lot of crud floating up to the surface and pouring out of the top of the filter. That's a good thing. I do it every year with our filter.

Once you've slammed and keep your chlorine levels at the ideal and follow TFP guidelines, you should not need to SLAM again for the entire season. If you asked around this forum, you will find many of us long time members never need to SLAM even at the beginning of the swim season, and most never SLAM during the season. Leslies has a video that tells people "you will most likely need to shock your pool 3 times during the swim season."
Don't believe it! TFP guidelines enable you to have a sparkly pool all season!

Keep up the good work Beachkimball!

 

[Beachkimball]

The water looks very nice to the naked eye, but I do not like the looks of that filter or what is on your finger. I would definitely start reading-up on the SLAM Process and do the Overnight Chlorine Loss Test as well. Some other things to consider if it's been a while:
- Removing the pool light to clean behind in the niche (if equipped); power off to the light
- Deep clean the sand

Not quite sure what those particle are. I don't recall getting those on my side of town. Almost look like parts of a rollie-pollie, but I haven't seem them out yet. Maybe just something from your trees?

Just thought I’d update you! I’ve been going crazy searching online and finally I’m 99% sure that those little green things are caterpillar droppings! Waiting for a reply from the A&M ag extension, but that would explain why I have slammed again and continue to pass the OCLT with now clean robot filters. As always, thanks for the help!

 

[rcerf]

I’m going through the same thing right now with the caterpillar droppings. They look exactly like what you show in your picture. Makes quite a mess. I would be interested to hear what A&M says.

 

[Beachkimball]

I’m going through the same thing right now with the caterpillar droppings. They look exactly like what you show in your picture. Makes quite a mess. I would be interested to hear what A&M says.

They confirmed it. (So glad its not some weird algae that was immune to SLAM!) Here’s what they told me: “It appears to be caterpillar droppings. There are some large ones in the trees right now - Buck Moths and wooly bears to name a few. They are likely dropping from the leaves, even if the tree isn't directly above the pool, the wind could be dislodging and sending them that direction.”

 

[mguzzy]

Bug poop, what an interesting moral to the story! Yes, I agree with @mariane , cleaning your Sand is easy, and it will make it run better. ...
Still curious about your FC. Did you figure out what happened there?

 

[rcerf]

Thank you for the follow up. Funny how they aim right for the pool?

 

[Beachkimball]

Bug poop, what an interesting moral to the story! Yes, I agree with @mariane , cleaning your Sand is easy, and it will make it run better. ...
Still curious about your FC. Did you figure out what happened there?

Unfortunately, not sure what happened there! Must have been a measurement issue, but I don’t know now. Maybe all the chlorine got me dizzy? Have never had that issue in the past. Oh well. As always, thank you all for the help!