Will Draining Water Help With Algae?

This got me thinking… what’s the plan after the SLAM process is complete? Will I need to add a gallon of LC every day? I assume there will be less frequent maintenance needed once I get a SWG installed, but until then, am I looking at adding chlorine daily?
In a word, yes. May not be a gallon...will be enough to maintain target FC for your CYA. FC/CYA Levels
 
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In a word, yes. May not be a gallon...will be enough to maintain target FC for your CYA. FC/CYA Levels
Thanks. Then I’m really glad I’m switching to a SWG. Daily chlorine will add up ($$$) pretty quickly. I don’t think I ever knew how much the sun was hurting my levels. I think I was able to do an ok job and maintained for a little, but once chlorine got depleted even a little, things would snowball extremely fast, then just got out of hand. That was happening once or twice a month between April and October.
 
Thanks. Then I’m really glad I’m switching to a SWG. Daily chlorine will add up ($$$) pretty quickly. I don’t think I ever knew how much the sun was hurting my levels. I think I was able to do an ok job and maintained for a little, but once chlorine got depleted even a little, things would snowball extremely fast, then just got out of hand. That was happening once or twice a month between April and October.
This is an important lesson that many new members learn. Depending on your pool size, exposure to sun throughout the day and your CYA level, will all affect the loss of FC per day. My pool is only 15k gal and during the summer in So. TX, I was using half gallon to a gallon daily. You learn this through daily testing and also find that you cannot dump and forget it. We were traveling more and had neighbors and nearby family members help but that was a pain for everyone. The SWCG became my best friend. Now I did it prior to LC prices going completely crazy. Think as a SWCG as prepaying your chlorine. You lock in a price today against future inflation of LC and pucks. The more you take care of the SWCG and the longer it lasts, the cheaper your unit of chlorine. Now SWCGs have a finite life but those that use it for 5 months of their swim season vs others that may have 10-11 months of swim, have different overall life spans.

So after you complete the SLAM, you will get your overall pool chemistry correct. If you have not yet downloaded the PoolMath app, suggest you get it. It becomes very helpful to track your testing and help with how much chemical to add based on your testing. Also it will track CSI which helps keep your overall pool water balanced and will help prolong your SWCG life. There is a free version and the premium version for about $8 annually is well worth it as it holds all your history and other features.

By testing your fill water now, it will help determine what other chemicals you may need for startup. For example, some local water is very high in calcium, where others may have low levels and need to add calcium.
You lower TA with Muractic acid as well as pH. Once you get a SWCG, you will need salt and also get the salt test kit. You already have stabilizer to get up to 60ppm CYA after the SLAM.
 
This is an important lesson that many new members learn. Depending on your pool size, exposure to sun throughout the day and your CYA level, will all affect the loss of FC per day. My pool is only 15k gal and during the summer in So. TX, I was using half gallon to a gallon daily. You learn this through daily testing and also find that you cannot dump and forget it. We were traveling more and had neighbors and nearby family members help but that was a pain for everyone. The SWCG became my best friend. Now I did it prior to LC prices going completely crazy. Think as a SWCG as prepaying your chlorine. You lock in a price today against future inflation of LC and pucks. The more you take care of the SWCG and the longer it lasts, the cheaper your unit of chlorine. Now SWCGs have a finite life but those that use it for 5 months of their swim season vs others that may have 10-11 months of swim, have different overall life spans.

So after you complete the SLAM, you will get your overall pool chemistry correct. If you have not yet downloaded the PoolMath app, suggest you get it. It becomes very helpful to track your testing and help with how much chemical to add based on your testing. Also it will track CSI which helps keep your overall pool water balanced and will help prolong your SWCG life. There is a free version and the premium version for about $8 annually is well worth it as it holds all your history and other features.

By testing your fill water now, it will help determine what other chemicals you may need for startup. For example, some local water is very high in calcium, where others may have low levels and need to add calcium.
You lower TA with Muractic acid as well as pH. Once you get a SWCG, you will need salt and also get the salt test kit. You already have stabilizer to get up to 60ppm CYA after the SLAM.
Thanks for sharing. Based on your pool size and location, I imagine I’d need to use the same amount of LC if not more. The SWG makes total sense if otherwise I’d need to add about 1.5-2 gallons LC every day for 5 months out of the year.

I just downloaded the app 👍. I also got my test kit. You think it makes sense to test the water now? Or should I wait until I drain, get the steps fixed, refill the pool, then test the “new” water? Based on my recent testing with test strips, the chlorine levels are higher than normal, but CYA is very low (basically 0). I bet the new test kit will provide more accurate numbers.
 
The SWG makes total sense if otherwise I’d need to add about 1.5-2 gallons LC every day for 5 months out of the year.
One gallon of 10% is 4.4 FC in 22.5k gallons and a skootch more than you'd use if your CYA was appropriate for the peak season. But still. That's $5+ a day, or $9+ a day if Home Depot is the only one left with chlorine this week.
You think it makes sense to test the water now?
Absolutely. Some practice never hurts and you'll fumble through the tests the first couple times.

I gather all the bottles I need for any one test and put them to my left, in order, uncapped. Then I pick up, make drops and put down on my right. Afterwards I recap them all and swap to the next tests bottles.
 
Thanks for sharing. Based on your pool size and location, I imagine I’d need to use the same amount of LC if not more. The SWG makes total sense if otherwise I’d need to add about 1.5-2 gallons LC every day for 5 months out of the year.

I just downloaded the app 👍. I also got my test kit. You think it makes sense to test the water now? Or should I wait until I drain, get the steps fixed, refill the pool, then test the “new” water? Based on my recent testing with test strips, the chlorine levels are higher than normal, but CYA is very low (basically 0). I bet the new test kit will provide more accurate numbers.
In addition to what @Newdude said - test your tap water or whatever you will use to fill the pool after draining. Only test pH, TA and CH of that as there will be minimal if any FC and zero CYA. Keep these separate from your pool test. On the app I created a second pool called Home Tap Water - I then put the test results there. These tests will provide an indication of what your pool water may be when you fill it. It won’t be precise because you are mixing it with some existing pool water but it is good info to know for future.
 
In a word, yes. May not be a gallon...will be enough to maintain target FC for your CYA. FC/CYA Levels
I used the calculator you provided in your link, and based on current CYA of 20 and selecting the "SLAM" option, it says my SLAM Level is 10. Does that mean I need to get FC up to 10? That would be about 2.5 gallons LC if each gallons raises FC by about 4. Also, my CYA is actually closer to 0, but 20 is the lowest I could select on the calculator.
 
I used the calculator you provided in your link, and based on current CYA of 20 and selecting the "SLAM" option, it says my SLAM Level is 10. Does that mean I need to get FC up to 10? That would be about 2.5 gallons LC if each gallons raises FC by about 4. Also, my CYA is actually closer to 0, but 20 is the lowest I could select on the calculator.
We talked earlier about adding stabilizer Upon refill. You need to have some, or between the sun and algae you will be adding LC every hour to maintain the SLAM level. The purpose of CYA is to help protect the chlorine you add so ideally you want 20 to 30 ppm CYA for a SLAM.
 
We talked earlier about adding stabilizer Upon refill. You need to have some, or between the sun and algae you will be adding LC every hour to maintain the SLAM level. The purpose of CYA is to help protect the chlorine you add so ideally you want 20 to 30 ppm CYA for a SLAM.
Got it. Thanks. So, once I get CYA go around 30 ppm, that’s when I add LC to get FC up to 10 ppm? Then maintain that throughout the process? Based on my test trips, FC is around that right now ha, but the pool is still a nasty green.

Edit: I still need to test with my new kit for more accurate level readings.
 

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So, once I get CYA go around 30 ppm, that’s when I add LC to get FC up to 10 ppm?
10 FC was for 20 CYA. 12 FC is for 30 CYA. And yes, you will do your best to hold 12 FC throughout the SLAM.

Screenshot_20230327_210207_Chrome.jpg

Edit: I still need to test with my new kit for more accurate level readings.
Agreed. (y)
 
Got it. Thanks. So, once I get CYA go around 30 ppm, that’s when I add LC to get FC up to 10 ppm? Then maintain that throughout the process? Based on my test trips, FC is around that right now ha, but the pool is still a nasty green.

Edit: I still need to test with my new kit for more accurate level readings.
@Newdude covered all the points and provided his nice chart for SLAM levels.

Suggest you read SLAM process again. You will need to test every 4 hours - even with a CYA of 30. You want to maintain 12ppm FC on a consistent basis. Just adding LC in the morning and waiting till the next morning will just prolong how long you will be in the SLAM process. Because as the chlorine will eat the algae, the FC will drop. The goal is to keep replenishing that chlorine to maintain 12 ppm. The better you keep it at 12 the quicker the process will go.

Obviously you can go a little longer at night because the sun is not trying to eat the chlorine, but maybe plan to test at 9pm or so and add chlorine to raise FC to 12 then get up early at next morning before sunrise and test again.
 
Update: I finally did my first water test with the Taylor K-2006 test kit. Here are the results:
  • Free Chlorine: 9.2
    • It took 46 drops of the R-0871 reagent to make the test water colorless. I bet I used over half the bottle! This will be pricey if I keep using that amount...
  • Combined Chlorine: virtually 0. One drop of the R-0871 turned water from pink to clear.
  • PH: 7.8-8.0
    • Acid Test: took 3 drops of R-0005 to lower PH to 7.2 (which I think is the target before SLAM)
  • Total Alkalinity: 80-90 ppm
  • Calcium Hardness: 140 ppm
  • CYA: a little under 60 ppm
What stands out to me is the FC and CYA. FC is pretty high for the pool to still be green, but I guess once I begin SLAM, I'll need to raise it even higher. CYA was much higher than I anticipated. When I tested the water with a test strip, the strip reads almost 0. The K-2006 read much, much higher. I'm not sure why it would be that high. I most recently added CYA (1 pound) on 4/10. The algae was looking really bad, so I added 4 pounds of HTH granular shock on 4/14 (don't get too mad at me! I just didn't want to waste any of the LC that I have). Maybe those packets increased the CYA?

The pool step repair guy will now be here on Thursday, 4/20, so I think I just see how the water does over the next 3 days, and will likely drain the necessary water Wednesday evening. The steps should be repaired sometime on Thursday, so I'll refill on Thursday evening or Friday morning at the latest. Once I refill, I'll run the pump for an hour or 2 to let it circulate, then do another water test, and begin SLAM.

I have 11 gallons of LC on hand right now. Does that seem like enough? I may add one gallon tonight just to help with the brushing and vacuuming I did today.

Edit: also, I failed to mention this from the beginning: my filter has a Nature2 Mineral system attached to it. I installed an new mineral cartridge on 4/10. I think that may have copper in it to help with chlorine. Will that matter for SLAM?
 
It took 46 drops of the R-0871 reagent to make the test water colorless. I bet I used over half the bottle! This will be pricey if I keep using that amount...
Use the 10ml sample size. Each drop is .5FC. There is no need for the .2 precision of the 25ml test sample. Will save reagent.
 
Use the 10ml sample size. Each drop is .5FC. There is no need for the .2 precision of the 25ml test sample. Will save reagent.
I was wondering about that. Of course I didn’t think to do that until after I did the test 🤦🏻‍♂️. I thought the 25ml, larger sample size would be more accurate.
 
I thought the 25ml, larger sample size would be more accurate.
Every measuring stick is as accurate as its markings. I never use a 25ml test...just no need for that level of accuracy. Taylor kits are accurate to +/- 1 drop, independent of the test.

10ml will be +/- .5 and 25ml will be +/- .2.

.5 is just fine.
 
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What stands out to me is the FC and CYA. FC is pretty high for the pool to still be green
Is it clear green?
, but I guess once I begin SLAM, I'll need to raise it even higher. CYA was much higher than I anticipated. When I tested the water with a test strip, the strip reads almost 0.
That’s why you can’t rely on strips- they probably got bleached out - that’s ok we’re starting over with accurate testing now 👍🏻
The K-2006 read much, much higher. I'm not sure why it would be that high. I most recently added CYA (1 pound) on 4/10. The algae was looking really bad, so I added 4 pounds of HTH granular shock on 4/14 (don't get too mad at me! I just didn't want to waste any of the LC that I have). Maybe those packets increased the CYA?
If the “shock” was trichlor or dichlor it added cya. If it was cal hypo it added calcium.
Once I refill, I'll run the pump for an hour or 2 to let it circulate, then do another water test, and begin SLAM.
Yes 👍🏻
I have 11 gallons of LC on hand right now. Does that seem like enough? I may add one gallon tonight just to help with the brushing and vacuuming I did today.
It’s definitely enough to get you started- have yourself a good source for more as you go through the slam. just save it for the slam. Your fc is right above target range now. That’s fine. You’re in a holding pattern until the drain/refill- we don’t want to possibly cause copper staining with higher fc levels.
PH: 7.8-8.0
  • Acid Test: took 3 drops of R-0005 to lower PH to 7.2
The ph test is invalid at fc levels above 10ppm so make no adjustments
The acid demand test is ok but not necessary- just use
PoolMath for calculations
Edit: also, I failed to mention this from the beginning: my filter has a Nature2 Mineral system attached to it. I installed an new mineral cartridge on 4/10. I think that may have copper in it to help with chlorine. Will that matter for SLAM?
This is very important information to mention.
Remove the full cartridge & replace it with the empty one now & don’t put another one back in - you don’t want copper in your water.
It doesn’t help chlorine or sanitize - it’s meant to be an algaecide & you can see how well that worked.
Hopefully most of the copper it added to your water will be removed with this water exchange & no staining will occur.
 
FC of 9 is right in range for maintenance for your CYA of 60. I would try to keep it there through the drain and repair work. As you can see it will not completely wipe out the algae, but will still fight it and keep it from getting worse.

Once you refill, re-test everything and start the SLAM. Hopefully your drain and refill will knock your CYA down to about 30 and save you a bit of $ on chlorine.

I second what Mdragger said on the Nature2. It is a bandaid at best, which isn't working for you and can cause more long term problems like staining.
 
Edit: also, I failed to mention this from the beginning: my filter has a Nature2 Mineral system attached to it. I installed a new mineral cartridge on 4/10. I think that may have copper in it to help with chlorine. Will that matter for SLAM?
This is another important lesson for new members. It really helps if we see pictures of your equipment pad and/or fully understand all of the chemicals you have added. Thanks for sharing and remove it as advised by others.

You also proved why we have no confidence in test strips - only the results from your own testing using one of the recommended test kits.
If you are draining half your pool then expect a CYA of about 30ppm - so dont add any more stabilizer until we see the test results of the pool water after you refill.

Suggest you now test your tap water.
 
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Is it clear green?
It's about the same green as the picture in my first post in this thread. I can't see the bottom of the 8 ft deep end, but I can see the bottom of the 3 ft shallow end.
Remove the full cartridge & replace it with the empty one now & don’t put another one back in - you don’t want copper in your water.
Dang it! I just got the new cartridge for $120 too. I guess it's a complete waste at this point? I'm not sure I can bypass the Nature2, and I already threw away the old cartridge.

Thanks for the replies! Sounds like my best bet is to hold where I am until the drain and refill. I ended up adding 1 lb. LC tonight, so now I have 10 gallons on hand for SLAM. Fortunately, the Wal-Mart near me seems to have tons in stock, so I shouldn't have trouble getting more. I may go ahead and order another 10 now just to be safe. Even after SLAM, I may need to add about a gallon per day until I get the SWG installed in mid-May.
 
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