green algae in the pool FC 7.5 CC 0

[samjesse]

Hi
I turned up the chlorination to max 8 for 10hr day for the last 3 days trying to get rid of this algae like I successfully did the last time it happened few months ago. But the algae is the same or little more.
How can that be with such high level of FC?
The pool is covered most of the time and the water temp is often 25+ d.c.
If I dump 1 gal of chlorine to shock the poo (never been shocked before except by leaving the chlorination to reach 20FC), will that raise the salt level, it is already high >5000.

PoolMath is updated

Any suggestions are much appreciated.

 

[mgtfp]

Hey Sam,

your chlorine is not that high. Without existing algae it would be on the high side of target, sufficient to prevent algae from developing. But not enough to get an existing algae bloom under control.

You'll need to SLAM:

SLAM - Shock Level and Maintain

We’ve all had to deal with a green pool. Clear algae from your pool with a SLAM! Read here to use shock level and maintain to clear your pool.

www.troublefreepool.com

And yes, that will require to turn off your SWG and use bleach. If you are concerned that your salt levels are too high, then you need to drain some water. Adding 100ppm of FC should increase salt by about 190ppm. I don't know "Leisure Pools" When I google that, theu seem to sell Astral Pools, which work up to 8000ppm of salt. Do you have a manual or a photo?

 

[samjesse]

Manual says no less than 3000ppm and should be around 4000ppm. I don't know how the algae developed with FC of 7. any way will slam after reading the link posted. Many thx

 

[Dirk]

In order to SLAM, you need to know your CYA level. Exchanging water to lower your salt level will also lower your CYA level, so take that into account. If your CYA is high right now, then exchanging water to lower both the salt and CYA will work out, since with a lower CYA you'll need less FC to accomplish the SLAM.

Shocking a pool is not always a sure fire way to rid yourself of algae. You need to elevate your FC to "shock level" and then "maintain" it there until the algae is gone for good. It's the maintaining that is key to the process. Read the SLAM directions thoroughly. There are no shortcuts. Perform the SLAM exactly as directed. The better you can maintain the shock level the sooner you'll complete the SLAM. If you cheat, thinking "Oh, this is close enough," you'll only be cheating yourself, in time and the extra expense of liquid chlorine...

Stay out of the pool stores (except to buy chlorine). They'll try to sell you magic potions to "help" with the process. That's a different kind of cheating. All you need is liquid chlorine. Anything else will just mess with the process and/or your pool.

 

[mgtfp]

I suspect when you had algae a few months ago, they were not all killed. Kept lurking in the pool, chlorine just managed to prevent an explosion. At some point it tipped, maybe one not even noticed dip in FC.

Do you have a link to your exact SWG? Many of the Aussie SWGs say exactly that, salt ideally around 4000, not below 3000. When looking up the exact specs, some show am upper limit of up to 8000.

 

[mgtfp]

In order to SLAM, you need to know your CYA level.

According to the PoolMath logs it's 60ppm. On the low side for SWGs, but good for a SLAM...

 

[samjesse]

Would regular laundry bleach work?

 

[mgtfp]

Not sure if there's any left in Australia that really is just bleach. They're always called "premium", which makes me suspicious. I suspect they all have some sort of "no-splash" miracle, which in the end makes the pool water foam. Or added fragrance. The Aussie bleaches also have only 4% strength, that's a lot of bleach bottles to be schlepped home. Due to the low strength it would actually be quite expensive.

I think you'll be better off buying liquid chlorine from the pool shop or Bunnings. If buying from the pool shop, then resist the temptation to come home with algaecides, which the shop will try to sell you.

 

[JamesW]

I don't know how the algae developed with FC of 7.

Almost definitely the fc was below 7 at some time.

 

[samjesse]

I will buy liquid Chlorine, can I also use some Glitz Premium Bleach bottles I happened to have some extra off at home 7 extra bottles. Sodium hypochlorite 42g/L (when packed), Sodium Hydroxide 9g/L , 2L/bottle.?

 

[mgtfp]

Is there a manufacturing or use by date on it? If It's old, then you risk just adding salt water without the benefit of chlorine.

Not sure if that one contains additives, never tried that one.

 

[Dirk]

I didn't see anything on the label that indicates it's anything but chlorine. Dose with it after the sun goes down. Test the water just before you do, and 30 mins or so after you dose, with pump running. If the FC goes up the expected amount (or just short of it, accounting for loss to algae), and there's no foam in the water, your bleach is bleach. If your FC doesn't move or goes down, your bleach is water.

 

[samjesse]

Ok, which is the best liquid chlorine to buy? I am reading online and trying to find what to buy. Will not use the bleach because not sure of its age and quality.

 

[mgtfp]

Doesn't really matter. As high in strength as possible, and as fresh as possible. Bunnings or pool shop I'd say.