Chlorine level drop quickly

[jdw-tx]

Hi,

I have a 25k gal inground gunite pool. The chlorine level drops to almost 0 after about 2 days after being shocked. PH and AL are within range. Shock is new, tabs are kept in floater. Not abnormally hot and pool is used very infrequently. Filter recently cleaned and turns over water about 3x/day. Yellow algae is forming on walls and stairs.

I also have a lot of small white particles floating on the surface of the pool. Initially I thought it was shock that didnt break down but it must be in the air because it keeps coming and I tried different shock. I'm stumped. Any ideas?:confused:

[CarlD]

You need to post all your levels.

It sounds like you either have no CYA or too much CYA.

Sunshine breaks down chlorine rapidly, without CYA.

Since you have algae, your strategy is wrong. You need to shock your pool and keep it shocked until the algae is gone. Read up on it on the various forums here. But you need to shock your pool 2 to 3x a day, testing your water constantly to keep it there until the algae is all dead, and stays dead.

Until then, any living algae will absorb your chlorine.

[jdw-tx]

Thanks for the quick reply. CYA is within range so I think you're right and the algae is eating the chlorine. I'll try shocking it multiple times a day.

Thanks again!

[PhantomAndy]

If you provide your chemical readings you will get more constructive help on how to get your water in shape.

I had an issue a big part of the summer last year, and it started back again this year after opening.

I thought I had my water straight (looked good), but my Free Chlorine was going away faster than I could put it in. I had a bit of an algae issue that wasn't terribly visible.

Using The Best Guess CYA chart will tell you what shock level to maintain. Get it there based on your CYA level, and do your best to hold it constant until you get to where you don't lose any FC overnight. Only then will you have the algae problem whipped. You can then let your FC levels return to the proper level based on your CYA level listed on the Best Guess chart.

[jdw-tx]

If you provide your chemical readings you will get more constructive help on how to get your water in shape.

I had an issue a big part of the summer last year, and it started back again this year after opening.

I thought I had my water straight (looked good), but my Free Chlorine was going away faster than I could put it in. I had a bit of an algae issue that wasn't terribly visible.

Using The Best Guess CYA chart will tell you what shock level to maintain. Get it there based on your CYA level, and do your best to hold it constant until you get to where you don't lose any FC overnight. Only then will you have the algae problem whipped. You can then let your FC levels return to the proper level based on your CYA level listed on the Best Guess chart.


It sounds like you had the same problem I'm having. I'm still trying to figure out all the tests to get my numbers straight. I've had the pool for 8yrs and never had a problem, just threw in some shock and I was fine.

[Watermom]

Any progress?

[jdw-tx]

Any progress?

Yes, I've kept it at about 12ppm for several days and brushed 2/day. The algae appears to be gone. Since I've started this its been cloudy & raining so I dont know if the cl will hold during a sunny day. I'm keeping my fingers crossed.

Can you recommend a good CYA test kit? I tried retesting after the pool store. They got 50 and I got 190+. I was using their number to base my best guess shock.

Thanks for all the help.