CH and CYA level?

[PoolStored]

So, the best way to handle this is increase your pool size by 500Gallons in pool math, add FC, test. If you still are not hitting target, add 500 again. Rinse repeat until you get the change you expect.

 

[henryforever14]

Last night, I put enough liquid chlorine to test at 16.5ppm around 9pm. Put another 64oz to get it to 20ppm (without testing though).

This morning at 7:40am, FC is at 16.5ppm. When I performed OCLT the previous nights, I always did around 5ppm and measured at 5:30am in the morning. I don’t know if that would explain the extra loss of chlorine measured today.

I also saw dust/sand gathering a bit on pool step and just a tiny bit on the floor. Last night was pretty windy. Not sure that’s connected.

I did also test CYA at 7:40am. I cannot see the dot at 40. At 50, I can see a little bit if I try harder.

My plan is to keep slamming going assuming 50 CYA, at least for today and tomorrow. Then I will do another OCLT to be sure.

Questions:

1. Are OCLT supposed to be done under high FC? I must have read somewhere that when FC is high, it degrades faster.

2. We are expecting some heavy rain this afternoon. And it’s going to rain quite a bit this week. Does that impact my ability to slam?

Thanks!

 

[Texas Splash]

1. Are OCLT supposed to be done under high FC? I must have read somewhere that when FC is high, it degrades faster.

Depends. When the FC is really high, it can be a bit tough to get a reliable/consistent OCLT result. But an FC of 20 shouldn't be that bad.

2. We are expecting some heavy rain this afternoon. And it’s going to rain quite a bit this week. Does that impact my ability to slam?

Not at all. Do your best to maintain.

The only other thing that caught my eye on your update above was the CYA test at 7:40 am. IMO, that is a bit early in the day and the sun hasn't reach a decent height above to influence the viewing tube. If you have storms today, another CYA may be out of the question. But next time you have a clear sky, I would do the CYA test anytime between 11:00 am and perhaps 4:00 pm. This should ensure you have good sunlight which may influence your CYA result. Hope that helps.

 

[henryforever14]

Depends. When the FC is really high, it can be a bit tough to get a reliable/consistent OCLT result. But an FC of 20 shouldn't be that bad.


Not at all. Do your best to maintain.

The only other thing that caught my eye on your update above was the CYA test at 7:40 am. IMO, that is a bit early in the day and the sun hasn't reach a decent height above to influence the viewing tube. If you have storms today, another CYA may be out of the question. But next time you have a clear sky, I would do the CYA test anytime between 11:00 am and perhaps 4:00 pm. This should ensure you have good sunlight which may influence your CYA result. Hope that helps.

Thanks! I will test when I get the chance. But based on what I had put in and how I lost chlorine so fast (implies <30 at the time), I’d say 50 is about the maximum it can get to.

It’s not always easy to test between these hours. Work get in the way and sun, well, get out of the way lol

 

[henryforever14]

Tested again at 11:15am. FC is down to 6.5ppm.

I don’t get the huge drop in daylight. The FC drop overnight is not proportional to what happens in the day.

It’s not particularly sunny today. It is windy though.

If it was from organic matter, shouldn’t CC show up? I consistently get maybe only 0.5 of CC. The water barely turns pink.

I did manage to test CYA again, it’s definitely over 40.

Any thoughts?

 

[Texas Splash]

Based on your CYA testing, it seems safe to treat your CYA as 50 for SLAM purposes which requires the FC SLAM level of 20. At the same time, continue all the other tasks on the SLAM Process. This may sound like a broken record, but it's true. You might also post a couple pics of your pool so we can see not only the water, but any potential areas that might require attention.

With algae, the FC can indeed fall quickly, and yours certainly seems to be showing large drops. Much more than I would've expected at this stage. We need to look at everything closely and not leave anything to chance.

 

[proavia]

When doing the Overnight Chlorine Loss Test, verify that the SWG is off or set to 0%.

 

[henryforever14]

Based on your CYA testing, it seems safe to treat yoru CYA as 50 for SLAM purposes which requires the FC SLAM level of 20. At the same time, continue all the other tasks on the SLAM Process. This may sound like a broken record, but it's true. You might also post a couple pics of your pool so we can see not only the water, but any potential areas that might require attention.

With algae, the FC can indeed fall quickly, and yours certainly seems to be showing large drops. Much more than I would've expected at this stage. We need to look at everything closely and not leave anything to chance.

Here are a couple of pics. Let me know if more is needed.

I had taken down the stairs on Friday. There were some rust inside the tube, which I brushed as possible as I can.

The light is nichless LED. I brushed the surface as best as I could.

The only variable between the 10 hours overnight and the 5 hours this morning is that this morning I ran the robot cleaner. Could it stir up what’s underneath? The floor looked clean. The robot only caught a few bugs and some sand/dirt.

Like I said, I don’t get the discrepancy overnight vs in daylight.

 

[henryforever14]

When doing the Overnight Chlorine Loss Test, verify that the SWG is off or set to 0%.

It has been set to 0%. The pump has always been running continuously.

 

[proavia]

The UV rays from the sun during daylight is what is burning off more chlorine in daytime vs nighttime.
UV penetrates clouds.

 

[henryforever14]

The UV rays from the sun during daylight is what is burning off more chlorine in daytime vs nighttime.
UV penetrates clouds.

I thought the 40+ CYA was going to protect FC better than this?

I’ve dumped more than 5 gallons of chlorine since last night. This is not sustainable long term.

 

[Texas Splash]

Henry, I went back to post #1 in this thread to review a few things and have the following suggestions/notes:
- While you opened the pool a couple weeks ago, the SLAM just started this past weekend. It is still very early in the SLAM process. Patience is key.
- As noted above, the sun's UV will certainly impact FC, even if there is CYA in the water. If you add algae to the equation, it can effect the FC that much more.
- The FC has dropped well below the FC SLAM level of 20 quite often. We understand life, work, appointments, etc get in the way, but those FC drops can extend the SLAM.
- Your pool and water look great. I see no red flags of anything that may require attention. You said the ladder is out. What about a main drain(s)? If you have a drain(s), when the water is tolerable and if you are able, you might consider removing the covers to inspect/clean in the drain area. They can accumulate junk over time.

Overall, I think you are doing pretty good, just need to try and keep the FC steady throughout the day as best as you can and remain patient. Brush everywhere once a day and monitor the filter pressure in case it needs a cleaning. Keep up the good work.

 

[henryforever14]

Henry, I went back to post #1 in this thread to review a few things and have the following suggestions/notes:
- While you opened the pool a couple weeks ago, the SLAM just started this past weekend. It is still very early in the SLAM process. Patience is key.
- As noted above, the sun's UV will certainly impact FC, even if there is CYA in the water. If you add algae to the equation, it can effect the FC that much more.
- The FC has dropped well below the FC SLAM level of 20 quite often. We understand life, work, appointments, etc get in the way, but those FC drops can extend the SLAM.
- Your pool and water look great. I see no red flags of anything that may require attention. You said the ladder is out. What about a main drain(s)? If you have a drain(s), when the water is tolerable and if you are able, you might consider removing the covers to inspect/clean in the drain area. They can accumulate junk over time.

Overall, I think you are doing pretty good, just need to try and keep the FC steady throughout the day as best as you can and remain patient. Brush everywhere once a day and monitor the filter pressure in case it needs a cleaning. Keep up the good work.

I do have main drains. But I wouldn’t be able to dive down to inspect it… I can’t swim.

I had suspected junk clogging the main drain. In another post, I described how my pump loses water level if I turn the skimmer completely off. But again, even if it’s clogged, I don’t know what I could do…

I will monitor things a bit more closely for the rest of the day and for tomorrow.

When I opened the pool, the pool guy dumped 2.5 gallons of liquid chlorine + a bottle of poly 60. The water turned clear in two days. (Can’t remember clearly, but very shortly.) There were a lot of dead algae and worms at the bottom. I subsequently hand vacuumed them out. After this, (I think all of this happened in 5days) I dumped in another 2.5 gallons of chlorine at noon, but that was all gone by 5pm possibly because I had little CYA and it was very sunny. (I know I should not have done it at noon, but I knew nothing at the time.)

The water, otherwise, looked very clear since Memorial Day.

 

[dBsooner]

I’ve dumped more than 5 gallons of chlorine since last night. This is not sustainable long term.

That (5 gallons of 10%), based on size of your pool (16000 gal), should have raised your FC by 31! That is an absolute monster of a drop.

Only two things use up FC: UV rays and pool goo. Losing that much overnight means UV isn't the issue. It's pool goo. There has to be something still living that is having a feast on your FC.

You are a cartridge filter, yes? When was the last time you cleaned your cartridge? Or replaced it?

 

[henryforever14]

That (5 gallons of 10%), based on size of your pool (16000 gal), should have raised your FC by 31! That is an absolute monster of a drop.

Only two things use up FC: UV rays and pool goo. Losing that much overnight means UV isn't the issue. It's pool goo. There has to be something still living that is having a feast on your FC.

You are a cartridge filter, yes? When was the last time you cleaned your cartridge? Or replaced it?

It’s 12.5%. But they were not added altogether last night. About 3 gallons last night and the rest of it this morning and also noon when it dipped to 6.5ppm.

I opened the cartridge filter on Thursday and cleaned everything. The filter does not look bad.

 

[RLP]

How old is the chlorine you are using?

 

[henryforever14]

How old is the chlorine you are using?

It’s from pool store. I think they refill it daily?

In any case, that shouldn’t be the reason because I do see the rise to >20 of FC

 

[dBsooner]

In any case, that shouldn’t be the reason because I do see the rise to >20 of FC

As long as you are definitely registering the increase, then you definitely have something eating your FC. Especially since you have a drastic loss overnight. Anything eating your FC sans the sun is bad.

 

[henryforever14]

As long as you are definitely registering the increase, then you definitely have something eating your FC. Especially since you have a drastic loss overnight. Anything eating your FC sans the sun is bad.

Yeah… I will keep pouring.

 

[dBsooner]

It’s from pool store. I think they refill it daily?

How much are you paying for a gallon? If it's more than 5.67 a gallon, you might try Walmart instead. I either get mine there or at Atwoods (you all don't have one of those, or a Menards) where they are almost always on sale. Right now 3.99 a gallon. So you may shop around to see if you can find somewhere selling them cheaper than the pool store.