What does algaecide do to kill algae

[coastal]

that chlorine doesn't?

I've had algae problems that it seems only algaecide will cure. Normally a little shock and I'm good but with this pool it takes more than that.

I have a pebble surface does this tend to allow algae to hide and grow easier?

 

[reebok]

see waterbear's post here:
best-time-to-add-algaecide-day-or-night-t12168.html
chlorine will kill it, you just have to follow the instructions in pool-school/ and be able to keep the chlorine at shock level consistently (as in multiple times per day. the pool school article recommends twice daily minimum, but hourly is much better and faster)

 

[duraleigh]

I've had algae problems that it seems only algaecide will cure.

Actually, the experience on this forum indicates that algaecide not all that good at killing algae but rather it is a good preventative.

Shocking the pool with chlorine is a guaranteed algae killer. Shocking is not a product you get t the pool store nor is it a one-time application of chlorine. It is a process over a period of days wherein you raise the FC high enough to sanitize the pool thru careful dosing and testing.

Pool School has a specific article on how to shock your pool.

 

[chem geek]

I've had algae problems that it seems only algaecide will cure.

Can you tell us the normal and lowest Free Chlorine (FC) level and the Cyanuric Acid (CYA) level when the algae starts to appear? Do you know if the algae is green algae or yellow/mustard algae?

Different algaecides have somewhat different mechanisms for killing algae, but none of them kill algae very quickly so are mostly used to inhibit (slow-down) algae growth allowing chlorine to kill them faster than they can reproduce.

 

[reebok]

he may not be referring to a preventative algaecide as normally thought of, but a treatment that is also labeled as an algaecide. for instance:
http://store.pinchapenny.com/product/Ch ... w-00000446
(hard to see in the picture but it says algaecide in the middle, to the right of the yellow part, written sideways.

 

[Guest]

he may not be referring to a preventative algaecide as normally thought of, but a treatment that is also labeled as an algaecide. for instance:
http://store.pinchapenny.com/product/Ch ... w-00000446
(hard to see in the picture but it says algaecide in the middle, to the right of the yellow part, written sideways.

This stuff is just sodium bromide! It takes the CYA out of the loop is all. I talk about it in the post that you cited above.

 

[chem geek]

(I wrote this while waterbear responded. I also talk about another similar product and agree that this is just a temporary workaround, not a permanent solution.)

Thanks for the clarification. Stop Yellow is Sodium Bromide. There are "treatments" for algae including sodium bromide which when combined with chlorine in your pool turns into bromine. There are also products containing ammonia (such as ammonium sulfate) and these combine with chlorine to produce monochloramine. These will both kill algae in a similar fashion to chlorine but they don't combine with Cyanuric Acid (CYA) so are typically used in pools that have high CYA levels. They basically "work around" the high CYA that makes chlorine less effective, but this is a temporary one-time solution and doesn't get to the root of the problem which is a high CYA level.

 

[coastal]

Well I thought I was keeping the chlorine high enough. I don't have the good testing kit yet but I did shock it while I was running the filter 24/7 and brushing twice a day, vacuum and clean out cartridge. The last shock it looked worse than before I shocked it. That's when I pulled out the algaecide ((poly [oxyethylene (dimethyliminio) ethtlene (dimethyliminio) ethylene dichloride] 60%)). After that, crystal clear water.
The aglae is yellow.

The few numbers I have are:

alk 100
ph 7.5
chl over 5

 

[reebok]

sounds like a pool store shock. the right way to shock can be found in pool school. that's a polyquat 60 which is the only algaecide recommended here, but like duraleigh said, it's generally more preventative than treatment. glad it worked for you though. I recommend getting one of the kits recommended in pool school so you can take control of your water and prevent this from ever happening again (if you're able to stay on top of it), or to clear it up cheaper if it does happen.

 

[Ohm_Boy]

Shocking isn't really just tossing a bag of powder into a pool and waiting on the clear to come.

Shocking to eliminate algae and organics in a pool consists of adding chlorine to achieve an FC level high enough to kill the organics in the pool and holding it there long enough to let it kill them. The proper level depends upon the amount of CYA in the pool.

Determine your proper shock level from the chlorine/CYA chart, and keep your FC level up until you don't lose any FC overnight, your CC is 0.5 or less, and your water is sparkling. You shouldn't need algaecide.

 

[coastal]

Thanks for the replies. I'm going away for for a bit and will be ordering the testing kit while I'm away so it will be ready for me to start using it when I return.

I like to stay on top of the pool water balancing so this kit will be great (and fun).