Newbie, green water/mustard algae?

dbs5150

Member
Jun 16, 2010
7
Eastern NC
Pool just installed 2 months ago. Water was nice for a while, but I never had a quality test kit until just two days ago and I now know that I have not had near enough chlorine in the water. I have seen a yellow colored substance on the floor of the pool and when brushed it turns to dust. I can usually vacuum the majority of it up and shocking with Chlor-Burst Dichlor helped once. I ran out of Chlor-Burst and decided I wanted to use the BBB method from now on anyway for convenience. Pool is now worse than it has ever been with green water and I need help!

I just purchased the TF-100 kit and results from yesterday were:
FC: 1.5
CC: 0.5
pH: 7.5
TA: 300-310 (very slight red color noticed at 30 drops, 31 was more noticable)
CYA: <20

Using the pool calculator to bring FC up to 12 tells me to add 372oz bleach - I just added 460oz for good measure, except I poured it around the perimeter of the pool and not in front of the return (is this important?). I know my TA is very high, but was surprised the pH was not also high. Do I need to add muriatic acid ASAP to bring that level down or should I concentrate on keeping the FC high and killing whatever is in the water? Lastly, the CYA is low although I read where it should not be 0 since I have used Dichlor before.. do I need to bring this up right away as well and I am also not sure how to do that. My pool does get direct sun light all day long, no shade until the sun goes down. It is also worth mentioning that 2 minutes after adding the 460oz bleach today we had a major downpour and I think that will continue through most of the night so I would imagine this got diluted.

How often do I need to check and what levels do I need to maintain? Thanks for your help, this site is awesome!
 

waskydiver

LifeTime Supporter
Jul 29, 2009
191
I'd go to the pool store and get some stabalizer. You want to target 30. This may be a little difficult if all you know is <20. Maybe raise it in 10ppm increments.

Pouring in front of the return is good practice. Some people pour into the skimmer. Around the parimeter isn't going to hurt anything. Some times I just remove the cap and float the bottle.

Concentrate on your FC, but I would target a lower pH... maybe around 7.2. Your chlorine is more effective there. You may struggle to keep it there for awhile, but that struggle will naturally reduce your TA.

During the shock, if you can test once an hour, that would be great. You want to maintain:

FC: 12
pH: 7.2

At some point, you are going to want to run a calcium hardness reading. Your TA is high enough that you may be running a high CSI. A high CH in addition to the high TA may warrent a more aggressive reduction of your TA. But, for now, maintaining the lower pH should keep you safe.

One more question: Is the yellow stuff that looked like mustard algae slimey?
 

crek31

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Jun 28, 2009
877
I think you cannot trust your pH test results during shocking, so you might do a search to verify that.
 

Bama Rambler

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Jun 22, 2009
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SouthWest Alabama
Welcome to TFP :wave:

You are doing the right thing by shocking. Test and add bleach as often as every hour untill you pass the overnight chlorine loss test.

Don't worry about the pH right now.

How much Dichlor did you put in it all together?

How were you chlorinating the pool before switching to liquid?

If your CYA is truly less than 20 you should bring it up to about 30 while shocking
Run your TA test again but this time wipe the tip of the R-0009 reagent between each drop. There have been reports of static electricity affecting the drop size and falsely increasing the drop count.

:hammer: slow typing got me again!
 

duraleigh

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I am going to suggest exactly the same things as mentioned above but I am going to suggest them one at a time.

1. Get your pool crystal clear by bringing your FC up to 12ppm with Clorox (or LQ) and HOLD IT THERE until your pool is clear. You will likely need a lot of bleach and this will probably not occur overnight. Just keep at it adding FC as often as you can....it's helpful to add it in the evening if you can.

2. Simultaneously, add enough Stabilizer (CYA, Cyanuric Acid) to bring your pool to 30ppm (use the pool calculator or ask for help using it.)

3. A day after adding the stabilizer, Adjust your FC level up to around 16ppm or so and HOLD IT THERE until your pool is crystal clear. Post back as soon as you see your pool clear and we'll help you adjust the rest of your parameters.
 

dbs5150

Member
Jun 16, 2010
7
Eastern NC
Thanks for the input - one more question for now.. since it is continuing to rain and it looks like it will continue through the night with a 50% chance tomorrow as well, should I wait on adding any more bleach and performing further tests? One thing it looks like I may have to do is drain some water since my water level has already risen nearly 3 inches and is now only 1/2 inch from covering the skimmer. Just checked a few minutes ago and this is the first time my pool actually smells like a normal pool.. I have had no chlorine odor until now.

Bama Rambler:
How much Dichlor did you put in it all together? I used 6 1lb bags of shock, but over a course of 4-5 weeks.

How were you chlorinating the pool before switching to liquid? I used and still use Blue Wave 3" chlorine tabs in a floating dispenser. This is my only other method of chlorinating other than bleach (and previously the dichlor). My pool is around 17,100 gallons but I am now setting the dispenser on the 25000 gallon setting.

waskydiver, yes the algae-appearing substance is slimey and is definitely multiplying. Also when I removed the pool ladder a good deal had accumulated beneath it, so this coupled with no trees near by I ruled out pollen. It is much thicker in some places than others and takes force and several strokes to brush it loose in the thicker/darker areas. So far this is only present on the floor, not on the walls yet.
 

duraleigh

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should I wait on adding any more bleach and performing further tests?
No. Shocking is a process wherein the chlorine must be held high continuously. Do not stop or let it drop below 12 now that you have started.

The rain, other than getting you wet, will have little effect on your pool chemistry....disregard it.

read "How to Shock Your Pool" up in Pool School. You will find you should be checking your FC at least twice daily and REPLENISHING YOUR CHLORINE LEVEL BACK UP TO SHOCK VALUE AT LEAST TWICE DAILY ALSO.
 

dbs5150

Member
Jun 16, 2010
7
Eastern NC
Thanks again - I checked the FC around 9:45 tonight and it was at 16 so I opted not to add any more bleach tonight and will check first thing in the morning and hope that it has not dropped too low.. if I wake during the night I may run out and test again as long as it is not pouring rain. I attached a pic of the algae I am referring to so maybe someone can confirm what this is and if there are any further measures I need to take. Should I be brushing the bottom (and walls) while I am shocking? Could I just hook up my auto-cleaner and let it run around?
 

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Bama Rambler

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The point of my questions was to determine approximately how much CYA you had added to yoru pool. According to canservative estimates of using 6 lbs of Dichlor and ½ tablet a day in the chlorinator you've added in the neighborhood of 50ppm CYA to your pool. I did this as a reality check because you said your CYA was below 20 and also if it is higher than 20 and especially close to 50 then your shock level is higher than your using and the attempt at getting rid of your algae will be futile.
 

dbs5150

Member
Jun 16, 2010
7
Eastern NC
Unless I am doing something wrong, I am surprised that this morning at 8am my FC was 15, only 1 down from last night, and the CC was 1 (I did not check the CC level last night). I was expecting the FC to have dropped much more over night with a higher CC. I am also suspecting that I need to brush the bottom in order to break up the heavier build-up and perhaps the chlorine can eat away at it better.

Bama, if my CYA is actually higher than what I thought based on the test, how high should I be shocking? I read where a CC of 12 should kill it and I am currently at 15-16. When testing for CYA with the TF100 I took it literally that I should not be able to see the black dot in the bottom of the tube when held at waist level; by the time I had filled it very near the top it was a little blurry but still easily visible. I may also be worth noting that I have added water to the pool 3 times due to evaporation because it gets so much sun light during the day - I don't know how many gallons have been added, but each time I've had to let the hose run wide open for 1.5 hours to bring it back to the appropriate level. I was low again yesterday but after the heavy rain it is now 2.5 inches higher than I usually keep it.
 

whoozer

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Apr 2, 2008
633
Acton Maine
Yes you need to brush all around during shock process, this helps to loosen things and then filters them. Sometimes algae can still be alive on walls as it makes a protective barrier and may not be affected by the shock unless brushed. Keep shocking, brushing, filtering, vacuuming.
 

Bama Rambler

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Like I said it was just a reality check. If your fairly certain you did the test correctly the number you got is good. Just continue using 15 ppm FC as the target for shocking.
 

waskydiver

LifeTime Supporter
Jul 29, 2009
191
Definately brush to break the barrier.

If brushing results in a greater chlorine demand, I would take your chlorine up to about 20 ppm. Yellow algae is pretty chlorine resistant and you need to hit it pretty hard.

But, the low chlorine demand that you are seeing so far is not indicative of algae.
 

dbs5150

Member
Jun 16, 2010
7
Eastern NC
waskydiver said:
But, the low chlorine demand that you are seeing so far is not indicative of algae.
I agree. Out of 5 tests now the CC level has been 0 once, 0.5 three times, and 1 once. The FC only went down by 1 over night last night, but then between 8am and 1pm it went down by 6, but I have to assume this was consumption by sunlight especially since my CYA reading was low. At this point the FC was only at 6 (dropped way too low I know), so I added 364oz bleach but did not check the FC again right away. Five hours later the FC was 12.5 with 0 CC and I had to leave so I added another 182oz bleach to make sure it did not drop below 12 again. Checked tonight at 10:30pm and the FC was 17.5 with 0.5 CC. I did not add any more bleach and will check in the morning to see how much is lost tonight. Ever since I brushed the bottom and walls good yesterday the water is very green now and I could not really tell if it cleared up any at all today. In the picture I posted above you could actually see the bottom and the stuff I am calling algae, but now you cannot make out the bottom of the pool (like an endless green sea), although you can see the brush on the bottom.

If my FC does not get used up and I still have no CC in the morning, what does this mean? If there is nothing to kill in the pool, is it green because the filter just has not had time to clear up the water and I've already killed all the algae? If it was not algae in the first place, could it have really been pollen or something else? I have a hard time with believing it is pollen just b/c of the way it looked on the pool floor, we do not have any nearby trees, and I would think my neighbor's pool who is surrounded by more trees would suffer as well. I have been running my pump continuously since I started shocking and tonight I am letting my automatic cleaner vacuum the pool. I will post my findings in the morning; thanks for all of your input.
 

JasonLion

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I suspect that it is pollen. Pollen and algae look extremely similar when they are accumulating on the bottom of the pool.
 

dbs5150

Member
Jun 16, 2010
7
Eastern NC
Test at 8:15 this morning showed a FC drop of 3 over night, so it finally did some work on something.. my CC level was 0 again. I ran the cleaner all night to see if it would clear up any more of the bottom, but I can't really tell much. This did allow for some of the green/yellow substance to accumulate in the skimmer though and I was able to put my hands on it for the first time, and I can't really say that it was slimey and it just whisped away between my fingers. Since I did have a noticable drop last night, at least now there is obviously something wrong so I will continue to shock.

Questions:
1) If this is pollen, how do I get my pool to clear up? (I noticed after shutting off the pump for about 2 minutes to disconnect the cleaner and then turning it back on that the return appeared to blow out cloudy water for about 5 seconds but then cleared up. I have a 150sq ft cartridge filter and I have not cleaned it yet, but it is brand new and has been ran only 2 months now over clean water until this bout I am struggling with now - pressure on filter still reads 11psi which it what it has been since the first time I turned it on. It is a modular media system that, according to Sta-Rite, only requires 1 cleaning per season under "normal" operating conditions.) Maybe it is still worth me draining the filter and checking out the cartridge and inside the tank?
2) Can a pool store test for pollen or algae in a water sample?
3) Is it normal for my CC level to continue being so low under these circumstances?
4) Should I raise my FC level even higher? I have been around 15-16 on average.

EDIT: As I read more I am also starting to be convinced that this is pollen as well.. I guess I've been having a hard time believing it at first because the big pollen season is over where everything outdoors turns yellow. I was thinking if this stuff was getting in the pool this much that I would see it in other places like around the outside of the pool or on my deck, etc. But, in addition to not keeping my chlorine levels right I was also not running my pump enough and probably allowing pollen to sink to the floor due to poor circulation. I am going to pick up a skimmer sock today and see if that helps catch this stuff and clear the water quicker. Please advise if there are other measures to help this problem.. I wish I had vacuumed it off the floor the other day like I have been doing in the past instead of brushing it.. the water was still clear until I broke it up all over the place.
 

mkenyon2

Well-known member
Nov 25, 2009
236
Cleona, PA
You mentioned rain, and a high water level. You may want to, once it's settled, vacuum to waste (if your filter lets you). Get it out of there. As to why it's in your pool but nowhere else, it may just be it got stuck in the water, but on your deck/patio/car the wind blew it off.

A 1 and 3 FC drop is not bad with a green pool. Chlorine will break down organics, including pollen and leaves. (I've seen some leaves in my pool that seem to have dissolved.) So chlorine will dissolve pollen, but won't remove it as fast as vacuuming. Skimmer sock, or anything that will catch the stuff will help.
 

dbs5150

Member
Jun 16, 2010
7
Eastern NC
I believe I am done shocking since my overnight FC once again only dropped by 1. I raised my level all the way to 21.5 (not intentionally) yesterday evening around 8pm and at 9am this morning it was at 20.5. It is cloudy today, but once the sun comes out it should drop it down substantially. I can see an improvment in the water clarity, although it is still green-tinted and murky I can see the bottom much better and see where there is still some pollen accumulation on the floor. I have a skimmer sock on now and continue to run my pump 24/7, alternating between vacuuming and just filtering. I guess it is just going to take some time to clear the water up.

In the meantime, should I begin fixing my other chemistry issues? TA is very high so I thought I better buy a few jugs of muriatic acid, and my CYA is also low causing me to lose lots of chlorine during the day with the direct sunlight my pool gets all day. Is there any particular stabilizer I should go after, i.e. does Wal-Mart carry something I could use or do I need to stop by the pool store or order online? I have not checked the pH since I started shocking, but it was 7.5 then.. should I aim lower? Never checked CH and do not know how important this is for me. I assume I need to try to main FC of 4-5 from now on?

Again, thank you for all your help. I'm sure I would have wasted a lot of money at the pool store with tests and treatments if it wasn't for your knowledge and assistance.
 

JasonLion

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WalMart sells stabilizer for a good price, though they are sometimes out of stock.

It is good to check CH at least once a year to make sure it isn't getting too high. With a vinyl liner you will be fine if CH is very low, but very high CH levels can still cause problems.

PH between 7.5 and 7.8 is fine for normal situations. If you need to lower your TA level, you want to keep the PH lower, say 7.2 to 7.5, until your TA comes down to where you want it to be.
 
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