OK an OCLT has begun with the SWG off for at least 30 minutes prior. Tonight's FC reading is 6.5
Black Algae, Wire Brush, New Plaster
- Thread starter edjanowsky
- Start date
OK an OCLT has begun with the SWG off for at least 30 minutes prior. Tonight's FC reading is 6.5
This morning's readings are as follows.
FC 4
CC 0
pH 7.4
I added a gallon of 12.5% bleach.
FC 4
CC 0
pH 7.4
I added a gallon of 12.5% bleach.
Re: IC60 Cell Light Off
This morning's FC reading is 4.
But I also tested last nights sample again this morning and it was 4.5, so using the same lighting conditions for both tests makes this morning's comparison more valid?, or there's also algae in my sample from last night eating FC. The latter seems more likely considering all the other data.
The pool was horribly mismanaged for its first few months. FC was allowed to drop so low and for so long that black algae formed. And even though the black algae has been scrubbed away as far as I can see, I guess its safe to say there appears to be something in the water consuming FC.
I only have two gallons of 12.5% bleach handy and the PS won't be open until tomorrow. I guess I can add those two for now and get some more tomorrow. Or do I really need to buy expensive bleach at the local convenience store today or make the 40+ mile round trip to Walmart?
This morning's FC reading is 4.
But I also tested last nights sample again this morning and it was 4.5, so using the same lighting conditions for both tests makes this morning's comparison more valid?, or there's also algae in my sample from last night eating FC. The latter seems more likely considering all the other data.
The pool was horribly mismanaged for its first few months. FC was allowed to drop so low and for so long that black algae formed. And even though the black algae has been scrubbed away as far as I can see, I guess its safe to say there appears to be something in the water consuming FC.
I only have two gallons of 12.5% bleach handy and the PS won't be open until tomorrow. I guess I can add those two for now and get some more tomorrow. Or do I really need to buy expensive bleach at the local convenience store today or make the 40+ mile round trip to Walmart?
- May 3, 2014
- 59,662
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Re: IC60 Cell Light Off
Last nights sample is not valid - but this mornings at FC 4 is. You need to fully SLAM this pool.
If you have a very high bather load it is probably best to do a SLAM with the pool closed, or during a period with a low bather load and diligent monitoring.
Ponder that and let us know which way you plan to go.
Take care.
Last nights sample is not valid - but this mornings at FC 4 is. You need to fully SLAM this pool.
If you have a very high bather load it is probably best to do a SLAM with the pool closed, or during a period with a low bather load and diligent monitoring.
Ponder that and let us know which way you plan to go.
Take care.
OUCH 
That is quite a drop in FC. It should be less than 1. Looks like something is still in the water or on the plaster. Now to see what to do about it. Here is my idea keeping in mind you really can't "close" the pool during the day:
-Use liquid chlorine to get the FC up to just under SLAM level during the day and early evening.
-Close the pool over night and push the FC up to SLAM level during the night.
-Brush the pool at least once a day. Try for twice a day if possible.
Once you see the FC is holding overnight at less then 1 you know you are good.
Just an FYI you can use hydrogen peroxide (the stuff in the brown bottle) to bring down FC if needed. I will leave it to you to look up how much H.P. is need to bring the FC down by ?? amount.
Kim
That is quite a drop in FC. It should be less than 1. Looks like something is still in the water or on the plaster. Now to see what to do about it. Here is my idea keeping in mind you really can't "close" the pool during the day:-Use liquid chlorine to get the FC up to just under SLAM level during the day and early evening.
-Close the pool over night and push the FC up to SLAM level during the night.
-Brush the pool at least once a day. Try for twice a day if possible.
Once you see the FC is holding overnight at less then 1 you know you are good.
Just an FYI you can use hydrogen peroxide (the stuff in the brown bottle) to bring down FC if needed. I will leave it to you to look up how much H.P. is need to bring the FC down by ?? amount.
Kim
Re: IC60 Cell Light Off
I really can't close the pool except for overnight. This may have to be the plan. I just wonder how effective it'll be. I mean, at CYA 70, will FC 20 kill the organics or does it have to be 28? Is it possible for one or two nights of FC 28 to eliminate the organics?
I'm going to need some help making a plan so any additional input from the group will be greatly appreciated!
OUCH
-Use liquid chlorine to get the FC up to just under SLAM level during the day and early evening.
-Close the pool over night and push the FC up to SLAM level during the night.
-Brush the pool at least once a day. Try for twice a day if possible.
Once you see the FC is holding overnight at less then 1 you know you are good.
Just an FYI you can use hydrogen peroxide (the stuff in the brown bottle) to bring down FC if needed. I will leave it to you to look up how much H.P. is need to bring the FC down by ?? amount.
Kim
I really can't close the pool except for overnight. This may have to be the plan. I just wonder how effective it'll be. I mean, at CYA 70, will FC 20 kill the organics or does it have to be 28? Is it possible for one or two nights of FC 28 to eliminate the organics?
I'm going to need some help making a plan so any additional input from the group will be greatly appreciated!
I like Kim's plan, but wonder why close at night? How about leaving SWG at 10% (0.8FC over 12 hours) to 25% (2FC over 12 hours) or off? Should the pool still be closed overnight? In a few days, close just once night for OCLT? Given my fascination with black algae, I'm curious to see when he is able to pass OCLT.
Nice to see the CC show up and even better to see them gone.
If you cart down to the pool store tomorrow to stock up on bleach/chlorine - be sure to check the dates! Nothing from before April (17 04) or so would be good.
If you cart down to the pool store tomorrow to stock up on bleach/chlorine - be sure to check the dates! Nothing from before April (17 04) or so would be good.
This morning's readings are as follows.
FC 3
pH 7.7
I ran another OCLT last night so the SWG was off. Seems clear SLAM is coming.
CC readings could be slightly tainted because last night's reading was using different and brighter lighting which could've made the CC easier to see where I couldn't see it in the daylight.
I'll certainly be checking the dates on the bleach. Thanks!
Re: IC60 Cell Light Off
I ran the OCLT again last night to double check. FC fell from 5.5 to 3. So I'll be at the PS when they open.
I'm concerned though with my ability to accurately "see" my CYA reading. FC 28 is safe to bathers at CYA 70. What if CYA is really only 60 and I jack the FC up to 28?
Is it safe to say the organics and today's bright sun are going to eat up 4ppm pretty quickly so don't worry too much?
I ran the OCLT again last night to double check. FC fell from 5.5 to 3. So I'll be at the PS when they open.
I'm concerned though with my ability to accurately "see" my CYA reading. FC 28 is safe to bathers at CYA 70. What if CYA is really only 60 and I jack the FC up to 28?
Is it safe to say the organics and today's bright sun are going to eat up 4ppm pretty quickly so don't worry too much?
I'm confused. I understand Kim's idea of closing overnight is to protect bathers from high FC, and also that it's more effective on the organics without bather contamination in the mix?
I don't understand why I would leave the SWG on or off during the SLAM?
Assuming CYA 70, what's the harm (with no bathers in the equation because the pool's closed at night) in going above FC 28 at night (to FC 30 for example because my math wasn't perfect)?
How long should I allow the bleach addition to mix in before testing FC to get the right reading?
Re: IC60 Cell Light Off
Will a SLAM kill black algae without using the metal pool brush on tiny spots I can't see without a diving mask and weight belt?
I guess if the black algae can be the cause of my FC consumption then an abundance of that FC can kill it?
Will a SLAM kill black algae without using the metal pool brush on tiny spots I can't see without a diving mask and weight belt?
I guess if the black algae can be the cause of my FC consumption then an abundance of that FC can kill it?
- May 3, 2014
- 59,662
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Re: IC60 Cell Light Off
Black algae is handled differently -- Pool School - Black Algae
I have been wondering - with your small pool water volume, could you not drain this pool and then do a SLAM on the new water? It should go really quick. You can keep the FC at shock levels and keep the pool open. It would just be best to test / dose every couple hours. You would only have to keep the swimmers out of the pool for 15 minutes if adding chlorine.
Take care.
Black algae is handled differently -- Pool School - Black Algae
I have been wondering - with your small pool water volume, could you not drain this pool and then do a SLAM on the new water? It should go really quick. You can keep the FC at shock levels and keep the pool open. It would just be best to test / dose every couple hours. You would only have to keep the swimmers out of the pool for 15 minutes if adding chlorine.
Take care.
I added a gallon of 12.5% bleach and a little less than a quart of MA.
The noon readings are as follows.
FC 7
pH 7.4
CYA 60
So even if you're not going to SLAM at full shock value, an elevated FC towards shock will expedite the sanitation of your pool and reduce FC consumption overall. While not TFP-doctrine, a "SLAM-lite" might be an easy compromise in your situation. Bring FC up to 1/2 or 3/4 shock with bleach and keep SWG high. Boost FC back to 50-75% of shock as needed if SWG can't maintain it until it can. This might be an alternative to drain/refill or full slam (potentially with closings) that would still improve your situation IMO.
Thoughts from people more expert than myself?
Thoughts from people more expert than myself?
I say close the pool at night for the reason you state-high FC levels + no bather load = fc better able to fight the good fight. I would leave the SWG off over night as I do worry it might push the FC up too high so your renters would not be able to use the pool the next morning due to higher FC levels. It is my hope the FC will be back down under SLAM level by the morning so they can enjoy the pool. I WOULD run the SWG during the day to keep it just under SLAM level. That will make it easy to push it back up to SLAM level at night.
Adding and testing FC or any chemicals- Add then run the pump about 15 mins and brush as much as you have time for then retest to make sure you reached your target level.
Kim
Adding and testing FC or any chemicals- Add then run the pump about 15 mins and brush as much as you have time for then retest to make sure you reached your target level.
Kim
Thanks Kim, that sounds good.
I rechecked CYA and found it at 60 so I'm aiming for FC 24. However, pool math says a couple gallons of 12.5% will get me from FC 7 to FC 24, yet an hour after adding the bleach, I'm only up to FC 15. Add another gallon now or wait till I close the pool tonight? I'm tempted to add it now.
I rechecked CYA and found it at 60 so I'm aiming for FC 24. However, pool math says a couple gallons of 12.5% will get me from FC 7 to FC 24, yet an hour after adding the bleach, I'm only up to FC 15. Add another gallon now or wait till I close the pool tonight? I'm tempted to add it now.