Got a bit of green - need assistance

mrramsey

Well-known member
Jul 19, 2014
169
Hudson Ohio
Hey TFP-ers. I am experiencing a bit of an issue. I am having a bit of green on the bottom. See the pic.

My FC is 4ppm CYA is at 40. Not sure why it is showing up now. Thoughts?

 

Patrick_B

TFP Expert
LifeTime Supporter
Jun 7, 2011
14,999
Midland TX
Easy, your FC is too low and has been too low. That's all there is to it. You need to SLAM and then maintain better FC at all times. Not meaning to sound rude, just being blunt. Do you have one of the recommended kits? You'll need it to get this done.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
More than likely it is algae and will require a TFP "SLAM". Can you post some test results from a TF-100 or Taylor K2006? That would be ideal.

SLAM is the term used when we “Shock” our pool to a higher “Level” of Free Chlorine (FC) and “Maintain” it that way until 3 objectives are met:
1. Water is clear
2. You do not lose any more than 1ppm of FC overnight (that's the OCLT)
3. CC (Combined Chlorine) is <.5
** You MUST meet ALL 3 items above to properly do a SLAM. Simply “spiking" the FC higher than normal isn't SLAMming, therefore there’s a good chance your algae will return.

To prepare for a SLAM, you should do the following:
- Adjust PH to 7.2 - 7.5; don’t worry about it after that during the SLAM
- Ideal CYA should be 30; the higher the CYA, the more bleach required
- Have a good amount of “regular” liquid bleach on-hand to keep your FC high at all times

Use the Chlorine/CYA chart (link in my sig) to bring your FC up to the proper SLAM level rating based on your current CYA and make sure it stays there (MAINTAIN) until you meet ALL 3 criteria listed above! That may take just a few days or even a week or two! That is absolutely critical for success.

At the same time, continue to run your pump 24/7. Remove any “muck” and debris, scrub all parts of your pool to expose any algae, and vacuum/clean (or backwash) filter as necessary. You may have to do this several times. It's a lot of babysitting, but with patience and consistency, you will succeed.

- - - Updated - - -

- Even with my cut & pasting, Patrick beat me to it. :)
 

mrramsey

Well-known member
Jul 19, 2014
169
Hudson Ohio
I have the TFP test kit. I am running the same parameters as I did last season. How is my FC to low at 4 ppm and 0 CC and a CYA of 40? The chart says 3 - 5 FC with a CYA of 40. Short of the stuff on the bottom the water is clear.
 

Patrick_B

TFP Expert
LifeTime Supporter
Jun 7, 2011
14,999
Midland TX
You've been lower or you would not have Algae. If it never got below 4 you would not see Green Algae growing. When you do, and you have 4 FC WITH 40 Cya, it's too low. You need to SLAM. When I say you've been lower, I mean you have been for periods of time.
 

pooldv

Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
Aug 10, 2012
25,408
FL panhandle
Depends when you test and when you add. Test in the early evening to see where you are. if you are at 4ppm at noon and everyone goes swimming then you will be below minimum FC level by the end of the day. I'm an aim for the high side of the range kind of guy. A little extra chlorine in the pool is not going to hurt anyone. I swam all weekend with chlorine well above 20ppm and CYA of 70 because I have some algae spots myself that needed some work because of too much swimming and not enough testing. My FC was 1.5ppm Saturday morning and then I spotted a few algae spots.

So, CYA of 40
minimum 3, target 5, shock 16
Means it is safe to swim when the chlorine is between 3 and 16.
Target is 5 because most pools lose about 2ppm of chlorine per day. But, if you have several people swim for 6 hours then you are going to lose more than 2ppm. Minimum level of 3 means that the level should never, ever drop below 3 ever.

I would target FC at 6 or 7 at all times and if you know there will be lots of swimming take it up to 8-10 before swimming, test after to see where you are and take it up to 8-10 again.
 

mrramsey

Well-known member
Jul 19, 2014
169
Hudson Ohio
Depends when you test and when you add. Test in the early evening to see where you are. if you are at 4ppm at noon and everyone goes swimming then you will be below minimum FC level by the end of the day. I'm an aim for the high side of the range kind of guy. A little extra chlorine in the pool is not going to hurt anyone. I swam all weekend with chlorine well above 20ppm and CYA of 70 because I have some algae spots myself that needed some work because of too much swimming and not enough testing. My FC was 1.5ppm Saturday morning and then I spotted a few algae spots.

So, CYA of 40
minimum 3, target 5, shock 16
Means it is safe to swim when the chlorine is between 3 and 16.
Target is 5 because most pools lose about 2ppm of chlorine per day. But, if you have several people swim for 6 hours then you are going to lose more than 2ppm. Minimum level of 3 means that the level should never, ever drop below 3 ever.

I would target FC at 6 or 7 at all times and if you know there will be lots of swimming take it up to 8-10 before swimming, test after to see where you are and take it up to 8-10 again.
Makes sense however We really haven't been in the pool all that much due to the cooler temps at any rate I will gear up for a slam and re-test after the sun goes down this evening. I do use Trichlor tabs in my auto chlorinator so I do watch the CYA constantly. I have also had to drain quite a bit of water due to rains. Oh and I do use my solar cover regularly when we are not using it.
 

Patrick_B

TFP Expert
LifeTime Supporter
Jun 7, 2011
14,999
Midland TX
Nothing wrong with that, especially when you watch the Cya. With this little Algae and clear water it ought to be pretty easy.
 

mrramsey

Well-known member
Jul 19, 2014
169
Hudson Ohio
OK so here we go...

My FC was 3.5 after the sun was off the pool. I added 2 - 121 oz bottles of 8.25% Wally world bleach + 8oz. 250 oz is what pool math indicated to add to get to 16ppm however when I tested I got 22 ppm. I will test again in the morning to see where it is. My CYA is also between 40-50 so I removed my trichlor for now.

I also cleaned the filter cartridge. It was nasty dirty.
 

Tepelus

LifeTime Supporter
Jun 4, 2014
121
Oslo
Looking at your picture of the pool made me think that you have a problem with the water circulation. It is possible that you have low chlorine concentration on the lower part of the pool if water is not well mixed up. I see that you have a robot. Put it to work. It will mix the water layers and bring the chlorine closer to the pool surface where is needed. Without a good chlorine distribution it is possible to have low chlorine concentration closer to the bottom of the pool if there is a temperature gradient and the water is not well mixed up.
 

mrramsey

Well-known member
Jul 19, 2014
169
Hudson Ohio
Looking at your picture of the pool made me think that you have a problem with the water circulation. It is possible that you have low chlorine concentration on the lower part of the pool if water is not well mixed up. I see that you have a robot. Put it to work. It will mix the water layers and bring the chlorine closer to the pool surface where is needed. Without a good chlorine distribution it is possible to have low chlorine concentration closer to the bottom of the pool if there is a temperature gradient and the water is not well mixed up.
I was not aware of that. My pump is on a timer and runs 3 times daily on low speed. Where should I point the return? Towards the surface or the bottom? I do have a "robot" but have had less that favorable results since it will not run on low speed very well.

At any rate I will test the water after I have my coffee this morning.
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
32,383
Sebring, Florida
Short of the stuff on the bottom the water is clear.
I am late to this dance but want to comment on this very common misinterpretation of what we see in our pools.

I am 98% sure your water is not clear. You have an invisible algae bloom and what you see on the bottom of the pool is debris that is largely dead algae. Your chlorine has killed some of it but is not getting it all so it continues to grow IN your water.
 

mrramsey

Well-known member
Jul 19, 2014
169
Hudson Ohio
OK this morning the water is a little cloudy. FC dropped from 21.5 to 17 overnight. I added 60oz of 8.25% bleach this morning to get back to 20 according to pool math. I'll test again at lunchtime.

I have some speculation as to why this is happening. This is the first full season and opening in the spring. Lots of maple trees with the helicopters and pollen fell into the pool. I did not have this extra organic load last year because the pool was installed mid July. I kept the pool as clean as possible read vaccuumed visible debris. Could the pollen built up in the filter cartridge be the culprit in this case?
 

Tepelus

LifeTime Supporter
Jun 4, 2014
121
Oslo
Keep the filter clean and the pump running 24/7 until the end of the SLAM. Any dirt in the filter will also increase the chlorine demand.
 

mrramsey

Well-known member
Jul 19, 2014
169
Hudson Ohio
Looked good for a while then we got rain, rain, and more rain. Now back to a green pool. Haven't tested the water yet today but leaving on vacation tomorrow for the week so I am sure I will come back to nastiness.

Beginning to regret putting a pool in N.E Ohio...