I'm in the midst of a prolonged "shock" cycle. Don't want to go into details. But, trying to understand the source of algae that may be gobbling up my chlorine in a clear, non-slimy, non-eye-irritating pool. Does algae reside in the filter? We use a cartridge filter with relatively low flow using a VS pump. Last time we cleaned it, a month ago, there was a huge amount of whitish residue, which I thought was from using Ca-hypo. No green or yellow. So, can algae accumulate in the filter??
Algae in the filter?
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Algae not only can but does accumulate in the filter, but it doesn't grow in the filter. Catching stuff is what the filter is supposed to do. If you're shocking correctly then the filter will catch the dead algae and it will be cleaned out when you clean the filter.
You really should go into details! Maybe we can help if you'll tell us how you're shocking and post a set of test results.
You really should go into details! Maybe we can help if you'll tell us how you're shocking and post a set of test results.
Algae will not grow in the filter. Algae requires sunlight. The inside of the filter is dark. So any algae in the filter is dead (or will be soon).
Thanks for the input. I'm on my way to a pool place to get my CYA tested (not that they know what they're doing!) to confirm my readings which are about 35-40 (after a 60% pool refill).
I'll post the gory details later today, but I've been shocking 2-3 times/day for 4 ,with bleach, using the pool calculator up to FC 16, CC 0.5. Last night the FC drop was from 17 to 12!!!
I'll post the gory details later today, but I've been shocking 2-3 times/day for 4 ,with bleach, using the pool calculator up to FC 16, CC 0.5. Last night the FC drop was from 17 to 12!!!
Here goes. After having trouble getting any chlorine level at all, with CYA>100, I did a partial refill around 60% on 7/10. I got CYA 30-40; pool supply gets 55-60. The water is clear, no visible algae, no dust when I brush, no eye burn, no slime. I've been shocking with liquid to FC 16, based on CYA of 40. But, I am having to add more and more chlorine twice a day, and overnight I am losing more. Last night at 11 PM, FC 17.5; this 8 AM: FC 12.0, CC 0.5.
Now I am going to shock up to FC 24, based on CYA of 60 (?)
Numbers on 7/16:
pH: 7.8
TA: 180
CH: 240
CYA: 40 (my test); 60 pool supply
So, I will try to maintain FC at 24 for a couple days, and see if I still get a large overnight drop.
Any other ideas? Thanks.
Now I am going to shock up to FC 24, based on CYA of 60 (?)
Numbers on 7/16:
pH: 7.8
TA: 180
CH: 240
CYA: 40 (my test); 60 pool supply
So, I will try to maintain FC at 24 for a couple days, and see if I still get a large overnight drop.
Any other ideas? Thanks.
The best thing you can do is keep after it. The more consistantly you can keep it at shock level, the better it works and the less time and chlorine it takes.
Bama Rambler said:
Thanks for the hand-holding. After 1.5 hrs, and a FC of only 15, I'm about to dump another 2 gallons to get to 24.
Just curious...
Did you watch the pool store do the CYA test? Did they re-check it and did you get to look at the tube?
I'm asking because your situation sounds like it could be an operator variable. Did you test till the dot was utterly and completely gone (your test)? The variable would be that the store tester might not have gone quite that far and a hint of the black dot remained, depending on the lighting.
If you use the images from the Taylor website for CYA testing, a hint of the dot remains in the image they say is test end. Confuses me a bit to tell you the truth as the difference between completely obscured and mostly obscured like the Taylor image shows is ~5-10ppm in my experience.
Did you watch the pool store do the CYA test? Did they re-check it and did you get to look at the tube?
I'm asking because your situation sounds like it could be an operator variable. Did you test till the dot was utterly and completely gone (your test)? The variable would be that the store tester might not have gone quite that far and a hint of the black dot remained, depending on the lighting.
If you use the images from the Taylor website for CYA testing, a hint of the dot remains in the image they say is test end. Confuses me a bit to tell you the truth as the difference between completely obscured and mostly obscured like the Taylor image shows is ~5-10ppm in my experience.
frogabog said:
I use the "dot completely gone" method, which gives lower CYA, and lower shock levels, which have not worked. The lady at the store uses a device that has the dot on a little handle, which she pulls up until she can just see the dot. So it works in reverse; she got CYA 55-60, which results in higher target level of FC for shock. I'll try that, because with my numbers, things are getting worse, not better.
JasonLion said:
Please have a look at my last posts, which include the details of my test levels, etc. I'm about ready to call the dump truck to fill the thing in.
I think you're right. The degree of accuracy on CYA test is +/- 10ppm anyway. The variation you're describing makes sense then.
+/-10ppm CYA doesn't always make a whole ppm difference in minimum and target (according to the calculator), but it always makes a difference for shock level. Missing shock level by even 1ppm is a whole different category than missing target by 1ppm. Shock level is much more important to make sure you're maintaining enough to do the job properly.
Don't give up, you're doing fabulous. The fact that you've realized you might not have hit shock due to CYA variation before you posted is awesome.
+/-10ppm CYA doesn't always make a whole ppm difference in minimum and target (according to the calculator), but it always makes a difference for shock level. Missing shock level by even 1ppm is a whole different category than missing target by 1ppm. Shock level is much more important to make sure you're maintaining enough to do the job properly.
Don't give up, you're doing fabulous. The fact that you've realized you might not have hit shock due to CYA variation before you posted is awesome.
How's it going? I'm curious because I'm going thru the same situation. After 4 days of shocking a clear pool and still loosing fc at night, I've moved up to Mustard Algae shock level this evening. I'm also looking for the 1 ppm loss and .5 tc. Hope we find it soon. 
captjohn said:How's it going? I'm curious because I'm going thru the same situation. After 4 days of shocking a clear pool and still loosing fc at night, I've moved up to Mustard Algae shock level this evening. I'm also looking for the 1 ppm loss and .5 tc. Hope we find it soon.
Finally, after 3 days shocking to FC 24 (CYA 60), my OCLT was 1, CC: 0. I was going to continue for another day, but today I found a significant plumbing leak, so I'm having to run the pump at really low speed, until it's fixed in the AM.
I'm still concerned because during the day, full, strong sun, My FC has gone from 22 at 8 AM, to 11 at 4 PM. I've not added any more bleach today, and will do another OCLT, and keep my fingers crossed. During those 3 days I was burning through around 8 gallons of bleach/day. Argh!
If I'm not mistaken your chlorine during the day at that high of a shock level will go down very quickly like that. It's the OCLT that you need to pass and it looks like you did, but it won't hurt to do it again. When I shocked my number was 22 also, but by late afternoon it was down to about 11, let it drift down the next day to about 6 (my target number) and it has remained a steady six during the day by bumping it up to about 8 every evening.
That's encouraging. I was getting very depressed over this. BTW, my pool has always been clear, but for a bit of green on the grout between tiles leading into the skimmer, which is always in the shade, and under a couple floats on the Polaris feeder hose.pepsiholic said: