Algae?

[Propbndr]

Whenever I vacuum my pool within a few days I see what appears to be a handful of algae spots show up in areas such as next to wrinkles in the liner or seams. They are a yellowish / green in color. Some vacuum up like "dust", others need 1 light scrub with the vacuum head to remove them. The spots take several days to come back and always in the same spots. Once they are back, they don't appear to "grow" in size.

Test numbers have been:

FC 6.5
CC 0 - .5
PH 7.5
CYA 80
TA 120
CA 175
Temp 68 - 72

To maintain my FC, I am currently running my filter 4 hours a day with my SWG set at 36%.

The water was crystal clear when I removed the cover. I scrubbed and vacuumed the pool and added enough granular chlorine to bring the FC level up to 31 which took many days to drop to "normal levels".

Question, if this is algae I really don't want to slam the pool, once I get into the pool would rubbing a chlorine puck on it over several days kill it?

 

[kimkats]

Why not SLAM the pool? You have algae in your water. It is settling on the wrinkles and growing. You need to SLAM to kill it. The puck will rub it off just like your vacuum head but it will not kill what is in the water.

Good luck!

Kim

 

[whalers11]

I just dealt with something similar. I was increasing my SWG output daily to keep up with a higher-than-usual chlorine demand. I thought for a few days I was losing the salt cell until I noticed small yellowish spots on the steps. Given the chlorine demand I slammed, then slammed to mustard algae level to be safe, and all seems well. Albeit, I'm running a FC close to 20 ppm as it slowly comes down to normal.

All that said, yours could likely be pollen, not algae. My tip off was the quick and overnight chlorine loss, but your setup seems to be running efficiently (4 hours at 36%).

 

[duraleigh]

When you can't determine whether or not you have algae, the OCLT (in Pool School) is often the best tool.

Shut off your SWG for the evening and perform that test and post the results.

 

[Propbndr]

OCLT results

8:00 pm (3 hours after filter run)

FC 7.0
CC .5
PH 7.5
CYA 80

7:30 ( 1.5 hours before filter run)

FC 5.0
CC 1.5
PH 7.5

I guess I have to SLAM it.

 

[Patrick_B]

That's ok, it shouldn't be too bad. Just hit it until you are done, follow SLAM procedure, and keep up with FC from here out. We can help if you need it, so ask questions when you have them.

 

[Propbndr]

Should I turn off the SWG during the SLAM process? I don't think the process would hurt it but, it might keep the FC levels artificially high.

 

[Azgirl71]

Should I turn off the SWG during the SLAM process? I don't think the process would hurt it but, it might keep the FC levels artificially high.

I kept mine off so I could get true readings of what my FC levels were.

 

[Propbndr]

Something weird happened. Pool Math calculated I needed 612 oz of 8.25% chlorine to raise FC from 7.5 (tested twice to be sure) to a shock value 31. I added 5 - 121oz jugs of bleach. Much to much to my surprise testing the next morning show a 55 to 60 value. I tested 6 times from 6 different areas of the pool to be sure. Testing was done using a brand new TF-100 kit.

Using Pool Math, I would have needed to add 1237 oz to get a rise to 55. Even if I made a mistake and added 4 - 128 oz jugs, the rise would only be to 33.

Any ideas of what the heck could have happened?

 

[kimkats]

My guess is that your gallons are off. Try measuring your pool again and see how many gallons it is.

Just an idea.

Kim

 

[Propbndr]

Used Poolcalculator.com. It says that my pool, which is 32' X 16', shallow end 3', deep end 6' holds 17200 gallons. I used 17260, which was given me by another pool volume calculator site.

I am really trying to get my head around this colossal screw up but, I guess there won't be any algae (or anything else for that matter) alive in my pool when the level gets to normal, probably sometime in July.

 

[kimkats]

I am stumped! I had high hopes.........

Okay a silly thought but it happened to someone else so I am going to throw it out there. What did you get the water out of the pool with? We had one person use the same cup they used to put the chlorine and shock (when they stilled used it) in with. Of course they read WAY high.

Kim

 

[Propbndr]

I use a measuring cup that is used for nothing else but testing. But, even if I used it to measure bleach, I rinsed it out and got a fresh sample 6 separate times from 6 different areas of the pool. Logic would dictate that after 6 rinsings that any residual bleach would be gone.

I will have to try a clean mason jar I have

 

[pooldv]

I was running through the math on PoolMath to see what I could see. Changing from rectangle to oval and depth from 4.5' to 4' gives a volume of 13,700 gallons. 605 oz of 8.25% bleach would raise FC by 29, which would give you 36.5. Still not close to 55.

I don't have any other ideas.

 

[kimkats]

The only thing I can think of now is you got some SUPER bleach!

I cannot find the bucket test for measure your bleach. I will keep looking. Hopefully someone will come along that knows right where it is.

Kim

 

[pooldv]

This one?
http://www.troublefreepool.com/threads/46345-testing-bleach-strength

 

[Propbndr]

Bump, any other ideas?