fighting algae again

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psteel6191

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Aug 6, 2009
15
Phila PA
Hi all

I'm fighting algae again in my pool and did an overnight test last night and got unusal results. To start I put 5gal (640oz) of 12.5% in the pool to get it up to shock level. First FC test after leaving the pool for an hour and a half with the pump running the solution of never turned pink. So I though maybe I have a serious dead spot in my pool. I took another sample from a different part of the pool and got a FC of 25. I was really suprised at the serious dead spot so I took another sample from the same spot. This time it was barely pink and when I added the R-087 drops it got more pink, has this ever happened to anyone before? As for the overnight test I got an FC of 25 from the good spot again this morning. The pool is still couldy green I'm not really sure what to do :scratch: Also my pool gets a lot of leaves and acorns in it since its under a maple tree, could this be causeing some of my algae problems? It has been very diffacult to clean the pool since its really cloudy and can't see the bottom to clean out the acorns and other junk.

FC = 25
CYA = 50
 
psteel6191 said:
I took another sample from the same spot. This time it was barely pink and when I added the R-087 drops it got more pink, has this ever happened to anyone before?
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Yep, just the other day. (Accidentally OD'd the spa.) Probably a smidge more powder would help.

psteel6191 said:
As for the overnight test I got an FC of 25 from the good spot again this morning. The pool is still couldy green I'm not really sure what to do :scratch: .

FC = 25
CYA = 50
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For algae, our rule of thumb is to keep shocking until the FC holds overnight (check), CC at 0.5 or less (?), and the pool is clear (nope). So, keep it at shock level for now.
--paulr
 
I'm going to guess here, but I'm thinking your dead spot is quite the opposite, but perhaps you are not using the fas-dpd test and just dpd? it sounds like the pink is getting "bleached" out to clear and when you add the reagent it's actually bringing your solution to where the pink is more noticable. 5 gals of 12.5% in your size pool should have raised your FC 30-35ppm.

That's just my guess...try adding some more powder to get the solution to turn pink before adding drops to measure fc.
 
Very good advice above. That said, I don't think you have any reason to perform the overnight FC loss test in the first place.

That test is preformed at the end of a shock/conversion process to insure all the organics are out.

If your water was crystal clear, yes, you should do that test. Until your water gets crystal clear, you should simply continue to shock your pool and not worry about the overnight FC loss.
 
Well the pool is really cloudy and green with algae I think. I have been brushing when I add the clorine, but its diffacult since I can 't really see the brush after it goes more than 3 ft into the pool. The Algae started when I moved into the house August 1st. I battled with it for a while untill I a guy at the a different pool store convinced me to add 15gals of 12.5%. I know that was overkill but it turned the pool blue. left the pool alone so the FC could drop and the filter could do its job. I replaced the sand in my undersized filter since the pool was really cloudy and would not clear up, but it never did. I was keeping the FC around 7 once ith dropped down from the 15gals. Well I let to drop to 4.5 at the begining of this week and bam green pool. I'm so frustraded with this pool. Please let me know if you need any other details.
 
Shocking is fairly simple but if one simple thing is overlooked, you are right back where you started. You have to shock to the appropriate level - you can find that on the CYA chart - you look for your CYA level and then in the right column is your shock level. You raise your FC up to shock level and hold it there, thru frequent bleach/chlorine additions, until the FC holds overnight (using an FAS-DPD test to confirm) or you lose 1ppm or less; your CC is .5 or less; and if you don't have an FAS-DPD test, the third criteria to know when you are really "done" is clear water. So if the algae wasn't really dead, it will come right back. So it sounds like perhaps you just aren't done shocking... are you using an FAS-DPD test? I apologize if I missed that it's not clear to me...
 
Well that's good that you have a good test kit.

But in other areas the FC is not so high?

What is the CC level?

I would keep shocking - if the water is still green and cloudy, then you still need to shock, and continue to brush. YOu should see visible progress each day.
 
Ok so here are some pics and updates.

FC = 21, added another 2.5 gals of 12%
PH = 8.0
CYA = 40-50
TA = 110

Pool28-27-09.jpg

pool8-27-09.jpg

pump8-27-09.jpg
 

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4.5 ppm FC with 40-50 ppm CYA producing a substantial algae outbreak is suspicious, especially for green algae. It also doesn't usually turn green like that in one day -- it usually starts out with the water looking dull, then cloudy and then green. Or if the green appears first, then it's in small patches before it grows more substantially. Now if the FC started out at 4.5 ppm in the morning and then dropped from sunlight to 3 ppm or 2 ppm, then I could see algae getting going and rapidly dropping the FC to zero and then taking off, but still over 2-3 days. This is strange.
 
Yes I added all 15 gals one night and the pool was blue the next morning. However the pool stayed cloudy for next two weeks and never really got clear, so I guess I never got rid of the algae the first time. Update pool is almost back to blue this morning so added a about 2 more gals of 12.5%, but did not have time to run a test before work.
 
Psteel...if the water is turning gray/bluish, you are headed in the right direction. With a 100lb sand filter, which seems fairly undersized for your pool, it may take over a week of the pump/filter running 24x7. Also, if you could run a skimmer sock while your home that may help speed up the filtering process.
 
Yeah i have no idea how the people before me could keep it clean with that filter but can't afford a new one right now, but I have been checking craiglist often. A new filter is top of the list for next summer. I will grab a skimmer sock and try that out. Thanks again for the advice.
 
psteel6191 said:
However the pool stayed cloudy for next two weeks and never really got clear, so I guess I never got rid of the algae the first time.
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Yup, that explains it. Though it's possible the algae may have been mostly dead, the cloudiness means that there was still dead algae to get rid of and until it's gone the chlorine demand is higher. This is why shock levels of chlorine are to be maintained until the pool gets clear -- it's not only faster for clearing (assuming decent circulation), but it prevents algae getting a foothold and blooming again.
 
Well I'm happy to say that for the first time I was able to see the main drain in the bottom of the deep end.:party: I have been keeping the FC round 20 and letting the filter slowly do its job. Since I could finally see the bottom I was able to scoop out some of the 50+ acorns on the bottom. I will post pics tonight.
 
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