Attempting to clear green pool - thoughts appreciated

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N

ncsukat

0
Apr 5, 2011
7
Pace, FL
Hello TFP! I am new to the site, but thought I would post to see if anyone has any additional insight to accompany the detailed posting about converting green algae from the main page.

Previously, I worked as a lifeguard and a CPO, however most of my work was on large systems (i.e. lap pools, not backyard). I have a general knowledge of the chemicals, but it has been a few years since I last worked on a pool. My husband is in the military, and a friend of ours is renting a house with a pool - we are stationed in the panhandle of FL. It had developed the worst algae bloom I have ever seen - but supposedly this pool was functioning reasonably well last season.

I am working with few tools - but trying to make the best of them. Having a good test kit would definitely help this situation, but as they are moving out soon I really don't want to spend $80 on the kits I'm used to unless it is really necessary. I was hoping that the local pool shops would do the testing the few times I need it - to get it back in good condition, but so far the two I have visited have proven their incompetence (or really, just a lack of looking at the big picture).

So far - I have gone through 40 lbs of granular shock and 12 gallon jugs of 10% liquid chlorine. I have also added approx. 40 oz of No Mor Problems and one full container of a granular Yellow Algae-rid product (both at the suggestion of the pool companies- I had experience with Algaecide 60 and wish I had used it instead at this point). After the first big shock and algaecide treatment there was a noticeable difference. All of the additional algae clumps on the top of the water I wasn't able to skim off disappeared and the water turned from a dark, yet clearish, forest green to a cloudy pea green. In small quantities and around the skimmers the water looks clear, but the bottom of the pool is still not visible.

I continued to shock with the granular chlorine, realizing that algae requires both diligence and patience. However, I was getting no results from shocking AT ALL. I determined that the FC level was pretty much staying at zero. At this time (it was Friday afternoon), I realized that I needed to reevaluate and be prepared for a weekend stock of chemicals. I took a water sample with me this time to get a more precise reading. The employee went away and came back and said you have no chlorine - DUH! Why do you think I came in? However, he seemed very knowledgable - and infact had maintained this very pool in his youth, so I stupidly took his advice. What did he suggest? To hit it harder - shock the heck of out it. So, I think - alright, maybe I wasn't getting the FC high enough. 20 lbs of granular shock later in less than 24 hours(his instructions indicated to shock and check until reaching FC of 5 or greater) I knew something was VERY wrong with this picture. After some thinking, I remembered that when stabilizer gets too high chlorine stops doing its job properly. So- I reevaluate on my own this time. All of that shock had obviously had a lot of stabilizer built in, so using granular was out of the question. Also, I needed to reduce my CYA - although thanks to not having a good test kit I wasn't sure of exactly what level it was, it seemed like the most logical issue.

So - I have now backwashed/rinsed, etc... until I cleaned out 6" of the top of this pool (approx 20x30 ft, 3ft - 10ft gradual slope (used to have springboard), and spillover spa). After fighting to find a good, useable water source-- the house has a nice well system for the pool only, but the well pump isn't working, the prime location is rusted shut, etc-- I FINALLY have the pool back up to normal level so the skimmers can help do some work again.

So - if anyone has made it through this novel of a post - does it sound like I'm on a better track now? I'm planning to use only liquid chlorine and continue to run the pump 24/7 until clear. The new test strips I have are indicating CYA of 30-50, but I wish I had a more accurate reading.

During this whole process, I have also been skimming out all possible debris, vaccuming, and brushing the walls/other surfaces to allow the sand filter to help me as much as possible.

If anyone can think of anything else I'm missing, please let me know. I am going to try to find another pool company that can actually do a detailed test today. If I am successful, I will post results later today.

Thanks for your time and knowledge!!!
 
Do you have the results from the pool store that you could post. Even though you basically said they have no clue it may help us direct you in the right direction. Without being able to do your own testing while clearing up a algae bloom is going to be tough since you need to be testing FC as much as possible and holding it at shock level.

Good luck and I am sure someone will be along with more help than I was.

You could order the TF50, which is only around 50.00 instead of 80.00

http://tftestkits.net/TFTestkits-TF-50-p55.html
 
You didn't post any reliable test results. Knowing your levels is critical. If the PH is too far off you won't make any progress, and if CYA is too high you won't make any progress. Test strips are completely unreliable for measuring CYA levels.

What specific kind of granular shock have you been using? If you have been using dichlor you are sure to have CYA problems by now. If you have been using cal-hypo then you need to know what your CH level is.

You have also been adding several things you shouldn't have, which are causing problems of their own. It takes huge amounts of chlorine to recover from using one of the "yellow" algae treatment product. If you didn't add chlorine at the right times you will be having additional problems from that. Likewise, several of the other chemicals you added are going to have side effects and won't help much. Algaecide is essentially ineffective while you have algae, it works much better to precent you from getting algae in the first place.
 
Thank you for your thoughts. I agree, the algaecide was a bad idea. There is a reason I am no longer going to seek their advice. The yellow algae product was added over two weeks ago.

The pool supply store I visited today was helpful in testing the water to obtain more accurate numbers.

When they tested, they indicated readings of:
pH 6.81
FC 0
TC 2.68
CYA 72

To clarify, these numbers were after draining and refilling approx 6-8" of the pool last night. After refilling, I added 6 gal of liquid chlorine (approx midnight). My test strips indicated a Free Chlorine level of 3 when I took the sample this morning. However, the pool supply store indicated that as being my Total Chlorine level.

After receiving these readings, I added 7.5 gal of liquid chlorine to the pool. This liquid was being pumped from the truck when I arrived, so it definitely wasn't sitting on the shelf like the other bottles losing efficacy. After adding and waiting over an hour for the chlorine to disperse around the pool, the test strip indicated:
pH 7.6
FC 10+ (much darker purple)

If I were the one renting the house with this pool it would be much easier to keep a close eye on it, but it isn't and I'm doing the best I can. I'm also pregnant, so that isn't making this process any easier. Anyway- I really appreciate the help. I will find out what type of granular I was using - I know 20 lbs of it was a popular brand - Super Shock It, I believe?
 
How big is your pool?

Your PH is too low. You need to bring PH up to between 7.2 and 7.4.

With a CYA of 72, your target FC level to shock is around 20+. If you don't add enough chlorine at one time to get the FC level up to 20 you won't make any real progress and will essentially lose the chlorine. Then you need to keep adding chlorine regularly, at least twice a day and preferably hourly, to get the FC level back up to 20 (or a little higher).

Super Shock-IT appears to be 65% cal-hypo. You should find out what your CH level is.
 
I may be in the wrong here, but not being able to stay on top of it, it is going to take a very long time to get it cleared. If you are not the ones renting and I see it is some friends renting, is there a reason why they are not taking care of the pool and you are?
 
I am working on the pool because my husband and all of the guys living in the house with the pool are flight students. Right now they are all on base for 12 hours 6 days a week, then they come home and study until they have to sleep. I haven't been able to get a job here due to the short time before we leave and the already high level of unemployment in the area - so my husband decided to volunteer my services to his friends.

Alas, the pool is getting much better! I can now see the bottom of the pool for more than half of the pool - just waiting for the deep end to follow suit. Hopefully it will be clear and usable by the weekend!
current stats as of last reading-
pH 7.2
FC 15+
CYA 71
TA 20

A few questions I have now:
1) I don't want to hurt my FC level, but I'd like to decrease my CYA if possible in order to increase the efficiency of the chlorine I am adding. I was thinking I could vacuum to waste the debris that I can now see on the bottom and refill the pool with fresh water to dilute the CYA?
2) I haven't backwashed the filter in a few days since I did a thorough backwash just before posting on this forum. I read somewhere on this site that the sand filter will do a better job of filtering out the fine algae if it is a bit dirty. Do you all agree? and how long is too long?
3) The water is currently sort of a turquoise blue. Will the color and clarity continue to improve as the algae is killed or cleaned up?
4) I know I need to raise my TA, but I have been hesitant to do so because I don't want to lose those chemicals when I vacuum. Am I hurting the effectiveness of killing the algae by allowing it to stay low?
 
1) Yes that will help, but probably only a little. It depends on how much water ends up being replaced.
2) If the water is full of algae, backwashing frequently is fine. Once partial transparency is restored it is best to postpone backwashing until there is somewhere around 6 psi increase in filter pressure
3) The water probably didn't start to get at all better until most of the algae was already dead. Continued filtering will continue to clean up the water, just be sure the algae doesn't get started again or it could get worse quickly.
4) Yes, TA that low is likely to cause problems. You should raise TA up to at least 50 right away. You probably won't really lose all that much water through vacuuming, but none the less it is best to hold off on raising TA above 50 until all of the vacuuming is done.
 
ThePoolNinja said:
When all else fails... Aqua Ammonia is your friend. 1-2 gallons depending on how bad the pool is.
Click to expand...
That really doesn't seem appropriate here. From the description the problem is already under control and all that is required is to give the filter time to do it's job. Besides ammonia frequently causes more trouble than there was in the first place, especially if you use it when you don't know what you are doing. Best to leave that kind of risk for a much more serious problem.
 

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All that's needed here is a little more chlorine. As Jason said, most of the algae is killed already. A few more days of shocking is much better than adding Ammonia to your pool. Besides, if you add ammonia, then you have to get rid of it too.
 
Thanks everyone. Yes, it is definitely working through the paces and is clearer every time I see it - progress in the deep end is slow going, but that's to be expected. I'll try to post pictures of the progression tonight! Off to do my morning check, take a sample to be thoroughly tested, and most likely buy some more liquid chlorine - so glad that I found a good resource for it! $4.50 for 2.5 gal at 10.5%! Also going to begin raising the TA.
 
Today's readings:

TA: 100
pH: 7.7
CYA: 78
FC: 10+
TC: 10+
CH: 225

TA has raised on its own, so I'm not planning to do anything with that anymore - will reevaluate when the pool is clearer.
However, CYA has increased slightly, so I'm going to attempt to lower it again.
 
I don't know what you are using for testing, but keep in mind that the CYA test is nowhere near as precise as the numbers you are reporting. Even the best CYA tests are +-15, and the ones from test strips using an electronic reader are usually much worse than that. Having CYA change from 71 to 78 probably doesn't mean anything other than CYA is somewhere in the 60 to 90 range.
 
Yes Ammonia is a last resort. However, if you think of all the money you spend on chemicals you throw into that green pool, and the long duration of time waiting for it to clear, it was a waste of time and money. I rarely use Ammonia, but it's a great alternative and bargain to every other algaecide out there including copper based. I've never had any residual issues with using Ammonia. So many guys in the industry are scared to use it, or hear bad stories about it, and the chlorine demand afterwards, however i've never had that problem. If you use it the right way of course...

But to the OP, sounds like you're almost there, so keep it up and it should be clear in no time.

And if your CYA is in the 70-90 range, that's a good place to keep it at. That's where i try to keep most of my pools.
 
Yes, in terms of a "get in, kill the algae, get out" sort of chemical, ammonia (ammonium-based chemicals) will do the trick because it will combine with chlorine to from monochloramine (if properly dosed in a 1:1 relationship) that will kill algae and is not moderated in its strength by CYA. So it can be useful in a high CYA pool that would otherwise take a lot of chlorine for shocking. Of course, if the CYA is that high, then water dilution is going to be needed eventually anyway so could be done sooner rather than later and then the shock level won't be so high.

After the algae is killed by monochloramine, you get rid of this chemical by further chlorine addition. That smells a lot because it produces lots of chloramines (including nitrogen trichloride), but it does eventually get mostly oxidized to nitrogen gas, usually in a matter of hours (to a day, if CYA is very high). So in that sense it's better than using sodium bromide which sticks around as bromine for a while or metal ions that don't go away except from water dilution or metal sequestrants (and of course they can stain). Usually though, chlorine alone works and helps oxidize what's left in the pool anyway -- something the monochloramine won't really do.
 
The pool is continuing to look exponentially better. A few pictures to demonstrate the progress!

2011-03-23_14-55-53_876.jpg
 
As others have said, I hope that is the beginning picture. When I was helping a relative clear a pool, I couldn't understand why it wouldn't clear up (I was advising him on the phone from 200 miles away) - *UNTIL* - I went to the pool and realized that he had not cleared out the foot of so of leaves sunk at the bottom. Like I told him after seeing that, he could have probably filled the entire pool with bleach and it still wouldn't have cleared up.

All I'm saying is that I hope all of that "stuff" floating on the top has been skimmed out, otherwise pretty much all of the bleach in town won't get it clear....
 

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