FC and CC with high CYA and algae now

Sep 4, 2015
110
Charlotte,NC
Had another post on it last week wanted to start a new one. So was getting some green stuff on walls and bottom last week, I vacuumed Sunday and cleaned filter. My CYA is somewhere between 160-180 based on a 4:1 dilution and doing the test a couple times to see where the dot disappears.(40-45) My CYA should be a minimum of 15 based on that and its where have been keeping it. I got the FAS-DPD kit last week so I could be more accurate and I was traveling this week so I brought it to 19 before I left. My wife added bleach on Tuesday and Thursday to keep the FC numbers and I looked today and its still FC 19 CC 0. I used a 2:1 dilution with distilled to measure so I didn't have to use 38 drops of reagent. In any case the green is back but the CC is still zero. I thought that if the chlorine was actively killing algae like a bloom your CC would be high like over 1? In any case this is what my bottom looks like is it possible its dead algea? Pool is crystal clear but getting this stuff in it. Thoughts? Try a shock? What levels?View attachment 43272View attachment 43273
 
You have been brushing, right? At least twice a day? Algae develops a film that protects it from chlorine. You need to brush it often to help break up the film.

Unfortunately, with algae already actively in the water, you have no choice but to SLAM. With that level of CYA you are going to need a truck load of bleach/chlorine to kill it all off.
 
The 15 ppm FC is the recommended level for maintenance, not for eliminating an active algae bloom. In order to rid your pool of algae, you need to follow the SLAM procedure. It's not a one time shock. It's a process of MAINTAINING an elevated FC level based on your CYA concentration until criteria are passed that confirm that the algae has been eliminated. See the link to the SLAM procedure and CYA/Chlorine chart in my signature. It's not practical or economical to SLAM a pool with a CYA level as high as yours. A partial drain and refill or multiple partial drains would be mandatory before attempting to SLAM the pool. A CYA level of about 60-80 would be best before attempting a SLAM.

Shock and pray is not something we teach here. The SLAM procedure is a method of reliably eliminating algae and making sure it's gone before resuming regular maintenance FC levels. Liquid chlorine aka bleach is the only recommended method of chlorination for the SLAM procedure.
 
If you want to know if there is an active growth in the pool, do an Overnight Chlorine Loss Test. Normally, those with a reasonable CYA would measure FC when the sun goes down, add CL to bring the FC to 10ppm, let the pool churn for at least 30 minutes, then measure the FC again before heading to bed. Let the pump run all night. Re-measure the FC before the sun hits the pool. If you lost 1ppm of FC or more, your chlorine is actively attacking something in the pool.

Now, with your high CYA level, it might take a lot of bleach raise the FC level even halfway to your SLAM level. ANd take a lot of test drops, which could increase your testing errors. This is one of the reasons that we suggest you lower the CYA level. It makes tackling issues much easier.
 
I know I am in a pickle with the CYA that high. I actually drained 18" out last month which was about 1/3 of the pool and CYA was still ridiculous. Good news is that my water bill was not as crazy as I expected. So I guess I am draining and refilling this weekend. Last time I used the robot hose and put it out of the pool drained pretty quick actually. This time ill vacuum same time so that nasty algae water goes out of pool not back into filter. Last time I think some of it made it back in.

I only want to take it down at most 1 foot at a time which is about 25% of volume. That takes me from 180 to about 130 first shot. Refill then one more foot 130 to 100. Refill then one more foot 100 to 75. finally one foot for 75 to 55. We will see how my math works.

BTW I did pool math and my FC needs to be 70 for SLAM needed 15 jugs to go from 19 to 70! its cheaper to drain and keep it at a reasonable CYA level for SLAM.

Man this sucks.
 
It is a bad situation. However, once you get that CYA down and stick to TFP methods, not using powdered shock or pucks you can avoid this situation in the future. It's a pain now but you're getting the knowledge to avoid it in the future so you can enjoy your pool.
 
If you are going to bite the bullet and reduce your CYA through draining, then you must be prepared to SLAM the pool to get it crystal clear.

You CANNOT drain off the "bad" water......algae is only eliminated through the correct application of chlorine.

BTW, there is no need to perform an OCLT test, you have plenty of visible algae in your pool. The OCLT is typically used to detect organics you cannot see.
 
I actually drained 18" out last month which was about 1/3 of the pool and CYA was still ridiculous.

I only want to take it down at most 1 foot at a time which is about 25% of volume. That takes me from 180 to about 130 first shot. Refill then one more foot 130 to 100. Refill then one more foot 100 to 75. finally one foot for 75 to 55. We will see how my math works.

If you truly have a 20,000 gallon free form pool, with many different depths, draining and replacing 18" of water is not 1/3rd of the pool volume and this is why your CYA is still high. One way to determine how many gallons you are replacing, is to add the amount of gallons you are adding. When you drain down 18", mark the starting point up top. When done, measure to determine how many inches you have dropped. Then perform a test with a few 5 gallon buckets to determine how much water you adding per minute.

For example, if you are adding 10 gallons per minute and it took 2 hours to reach the 18", then you have added 1,200 gallons in total, which is only 6% of the true volume. Pool Math will give you a rough idea on how much you will need to drain/fill to reach your goals.
 
One word of advice with high CYA: Drain it.

I was in the same situation a couple of months ago. I even used that BioActive (new) product. Only to find that the best solution was to drain it.

I drained a foot of water at a time, until my CYA was in the 30's. I'm confident that my pool is properly sanitized now. Do it. You won't regret it.

Sent from my Nexus 5 using Tapatalk
 
One word of advice with high CYA: Drain it.

I was in the same situation a couple of months ago. I even used that BioActive (new) product. Only to find that the best solution was to drain it.

I drained a foot of water at a time, until my CYA was in the 30's. I'm confident that my pool is properly sanitized now. Do it. You won't regret it.

Sent from my Nexus 5 using Tapatalk
I guess I meant to say "two words" :)

Sent from my Nexus 5 using Tapatalk
 

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just took about 18 inches and refilling now. we shall see what the CYA is in the morning. my guess is in the 120-130 range. Ill redrain a foot and repeat. It looks like it will take 4 or 5 of these 1 foot or so drain and refill to get to 30's. Then I will do a SLAM and get rid of what's in there. I am using the large return that powers my robot so water is exiting the pool faster than I can get it back in! I hooked the robot hose and dumping it down a French drain in the backyard. Tomorrow if it ever stops raining I will remove filter and vacuum the bottom and dump all that algae that's on the floor out of the pool at least that will help the SLAM a little.
 
SO just wanted to give a update some kinda good new and some other bad news. I have drained my pool approx. a foot each time and refilled 3 times now. So approx. 3 feet. My pool is 576 sq ft so 576 X 3 or 1728 Cu ft or 12,00 gallons. My pool is a odd lagoon shape with a lot of 3' some 4' and a 5.5ft deep end. I think avg depth would be around 4ft for gallon est. is My CYA levels have not appeared to drop much. Appears to still be sitting at 150 using 2:1 dilution with distilled so it may have gone down slightly. I am under the impression the CYA might have been much higher due to inaccuracy with dilutions. I've been out of town for 3 days and wife has put bleach in I raised the FC to 22 and the pool looks better really no where near the green on the bottom I saw earlier. Unfortunately you can't drain much more than a foot with a vinyl pool or you could have some liner issues. Otherwise I would just drain the whole thing. I am probably going to have to drain 1 foot off 10 times to get the CYA down. This sucks.

Now for some potentially bad news. I have been draining and filling and had the water to the middle of skimmer when I left Monday. Valve for skimmer feed is off. Came home and water was below skimmer so I have a fairly large leak. Its only in the 60's so doubt its evap and we had some rain as well. Hose has been running almost 5 hours to get it back up. Dropped some food coloring not seeing anything getting sucked in by skimmer gaskets. However I was able to get a 1/2 turn on the screws so thinking with removing that much water the liner and gasket may have slipped hopefully tightening will fix. UGHHHHH.
 
Are you positive the wife did not drain while you were gone?

A liner pool can leak from the main drain, near the light niche, returns and skimmers. You could also have rips and tears in the liner.

My neighbor left for vacation and came home to an empty pool. It appears that the dog cut into the liner on the steel walls. Chances are that the water dripping removed some soil on the bottom and the liner pulled and ripped. His was hard to tell and he needs a new liner.

Maybe you have some damage to the liner and it went unnoticed for a while. When I ask people how many times they have patched up a liner in 10 years, most people say "never", which I find strange.

Sorry to hear about this issue. Please keep us posted!
 
The liner was replace 3 years ago with a heavy duty one. Steel wall were checked for rust etc. I have not had any issues, and now after 3 1 ft draining's I am losing water so my guess is something got stretched and is leaking. I just filled up maybe 3 hours ago and its down a half inch I have it marked. Also did the bucket on the step test too and it hasn't budged. Plus I still have the CYA issue now its leaking. And Its going to be close to freezing this weekend. I normally don't cover and run the pump to keep it flowing when it gets cold, however now its leaking and will be hard to keep it up so the skimmer flows too. Im kinda hosed and I travel a lot so I need to figure this out quick. My initial guess is the skimmers cause it seemed to stop there would a pool store carry the gaskets if I take the plates off?
 
I do not believe this weekend will be where temperatures drop that low, especially in North Carolina. Even if the temperature dropped for a day, this would not be an issue. Edit - I just looked at the weather and you are correct 33 and 30 in NJ. Winter is on it's way.

Did you drain 1' from the middle of the skimmer? If so, this would put you 6" down below the skimmer. Or 1' below the skimmer?

Many people drain below the returns during closing, so this is a tough one. If you isolate the leak at the skimmer(s) and do not want to be frustrated, maybe calling in the same liner company may be your best bet. A service call these days should not be too bad (hopefully).

Does the leak stop once water is below the skimmer? If so, is the water still in the skimmer housing where the basket lies, or has that completely drained down as well?
 
so still leaking pretty good at least 1" a day. Good news is I put plugs in the returns and its below the skimmers and its still leaking, so it appears to not be plumbing unless its the main. I used food dye in the obvious places light, by stairs etc nothing.

Looks like scuba guy is next to find it, they charge $500 to find leak and will give 3 vinyl patches as well. Does that seem the going price? Any recommendations in Charlotte NC area?

Good news is algae appears to be gone and pool is looking real good. Also will be adding another foot of water today the leak place wants the pool filled up to skimmers. So this is 3 1/2-4 FT! of water I have replaced. and last test it was still sitting at a CYA of 150 using 2:1 dilution. Crazy...
 
I would not fill up the pool and hold off for a couple of days. If you are at 1” per day, it is not a major leak, but still a leak. If you plugged the returns, I would allow the water to continue to drain below the returns to determine if this is the issue. Maybe it is a gasket in the returns (hopefully). If not, and the pool continues to lose 1” per day, then it is either in the stitching or the main drain.

You can speed up the process (which is recommended as 1" per day would take a long time to get below the returns) by closing off the skimmers and dumping water on “waste”, which will drain water out of the main drain. Drain about 2 “ below the returns and stop there. Dry the area and place a piece of painters tape 1” above water line and in 24 hours, you will know if you have more of a leak.

After this, if you continue to lose water, then you have pinpointed the areas in question. Have you possibly lost soil under the concrete/vermiculite base, and/or near main drain that is visible to the eye? Maybe some of the stitching pulled apart somewhere in the base.

If the leak continues, then clearly a professional diver is needed, unless you are real handy. Regarding the cost of the service call, hard to tell. Most companies will give you a price based on the service call, which includes the first 30 minutes or hour in the price, plus an additional cost for each 15 minutes afterwards. When I was looking for someone to change my light niche ring because of rusty screws, the cost was $90 per hour + I would order the parts. Because this is a diver and they may need special equipment, then the price probably increases accordingly and then the higher cost is warranted.
 
I reached out to the guy that built the pool and put the new liner in and he swung by earlier. He found the leak in like 3 minutes. In the time it took me to drop my daughter off at high school and come back(maybe 8 minutes, he had gotten there looked and found it and we cutting a piece of patch. It was in a area where it transitions from wall to floor and he said this is prone place probably got it with the brush(which I was using the last week to get rid of algae) Anyway he cut the patch put glue on it. balanced it on the end on the skimmer pole pushed it right down onto the tear. Crazy magician! he knew exactly where to look and found a tiny leaf that didn't move when he disturbed the water with the brush. He wouldn't take any money he is a really nice dude.

So my algae looks like its gone, ill measure the CYA again tomorrow to see if it made any progress. He also said I can drain a couple feet off at a time don't have to worry about liner and just do a foot at a time. So now back to my original goal of reducing CYA. I need to get the CYA to a reasonable level so I can SLAM and put it to bed for the winter.
 
Great news. He is either a "real magician" or he knew where it was because of experience. Good news is he found the leak. The base stitching is a lot stronger then the side as you can see the lips. Hopefully this is the last of the leak. How big was the tear in the liner? Was it evident or you could not see? Just curious?

When I brush or vacuum the pool, I take my sweet old time so there is no damage to the liner. Depending on how many returns you have and where they are located, you may want to look into the 360* rotating heads. I swear by them. I have 4 of them and they really mix up the water real well. The other 2 are normal and 2 in the steps. This may cut down on the brushing part. In addition, I never veer off my levels. My minimum is always about 1 ppm higher than the recommended based on my CYA. Never had any issues with algae in the 2 years that I have owned the pool.
 
I reached out to the guy that built the pool and put the new liner in and he swung by earlier. He found the leak in like 3 minutes. In the time it took me to drop my daughter off at high school and come back(maybe 8 minutes, he had gotten there looked and found it and we cutting a piece of patch. It was in a area where it transitions from wall to floor and he said this is prone place probably got it with the brush(which I was using the last week to get rid of algae) Anyway he cut the patch put glue on it. balanced it on the end on the skimmer pole pushed it right down onto the tear. Crazy magician! he knew exactly where to look and found a tiny leaf that didn't move when he disturbed the water with the brush. He wouldn't take any money he is a really nice dude.

So my algae looks like its gone, ill measure the CYA again tomorrow to see if it made any progress. He also said I can drain a couple feet off at a time don't have to worry about liner and just do a foot at a time. So now back to my original goal of reducing CYA. I need to get the CYA to a reasonable level so I can SLAM and put it to bed for the winter.
You can't tell if the algae is gone by simply looking. Once you have the CYA at a reasonable level you should do an OCLT to determine if there is still organic matter in the pool.

I realize that you plan to SLAM (and rightfully so), and passing an OCLT is one of the three criteria needed to be met for a successful SLAM. I just want to make sure you understand that algae could still (and most likely is) be lurking.

Dom
 

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