Can't Get Rid of Algae

[matthewnadeau]

We have an in-ground pool which is about 7 years old. It's about 15,000 gallons with a Pebble Tech surface. I have had very few problems over the years with algae, but since Spring I've really had a problem getting control of it. We live in Northern California where it regularly reaches 90 - 100 deg and I've been keeping our chlorine level up over 5ppm and shocking the pool about every two weeks, but the algae keeps coming back. We brush the side of the pool, super-chlorinate, etc. but nothing has worked so far.

The only difference that I can think of compared to prior years is that I recently changed out our pool cleaner. We had a Hayward Navigator and I changed to Hayward Pool Vac Ultra (right about the time that we started to have the algae problem). Based on the cleaners instructions, I reduced our clean time from 5 hours with the old Navigator down to 2.5 hours with the new cleaner. I assumed that the shorter clean time may be contributing to the algae problem so I increased it to 4 hours per day last week, but the algae came back strong this week.

My typical water balance treatment is:

3 Cl tabs in the skimmer basket
Shock every 2 - 3 weeks
Check pH and Alkilinity every couple of weeks with acid addition about every 2 months and baking soda addition about every 3 - 4 months.

Other than that, our water tends to be pretty stable.

Any ideas on how to get control of the algae?

[doggie]

You probably won't get many replies until you accurately test your CYA and post the results, especially when you use the tabs.

[JohnT]

I've been keeping our chlorine level up over 5ppm and shocking the pool about every two weeks, but the algae keeps coming back. We brush the side of the pool, super-chlorinate, etc. but nothing has worked so far.

You are using tablets, so your CYA is probably out of sight. This requires much higher chlorine levels, which you can see at the top of the Chlorine forum. Running at 5ppm won't do anything to get rid of the algae, nor will shocking every two weeks. You have to shock the pool, probably raising the chlorine to at least 20ppm, and keep it there for several days. This will require testing the water several times a day, and adding more chlorine almost every time you test.

Get some good test results, particularly for CYA to get specific advice.

[eckardsl]

We have an in-ground pool which is about 7 years old. It's about 15,000 gallons with a Pebble Tech surface. I have had very few problems over the years with algae, but since Spring I've really had a problem getting control of it. We live in Northern California where it regularly reaches 90 - 100 deg and I've been keeping our chlorine level up over 5ppm and shocking the pool about every two weeks, but the algae keeps coming back. We brush the side of the pool, super-chlorinate, etc. but nothing has worked so far.

The only difference that I can think of compared to prior years is that I recently changed out our pool cleaner. We had a Hayward Navigator and I changed to Hayward Pool Vac Ultra (right about the time that we started to have the algae problem). Based on the cleaners instructions, I reduced our clean time from 5 hours with the old Navigator down to 2.5 hours with the new cleaner. I assumed that the shorter clean time may be contributing to the algae problem so I increased it to 4 hours per day last week, but the algae came back strong this week.

My typical water balance treatment is:

3 Cl tabs in the skimmer basket
Shock every 2 - 3 weeks
Check pH and Alkilinity every couple of weeks with acid addition about every 2 months and baking soda addition about every 3 - 4 months.

Other than that, our water tends to be pretty stable.

Any ideas on how to get control of the algae?

It seems people forget to mention mustard algae. You dump chlorine all day and you won't get rid of it. You need polyquat60 which you can buy at Walmart. Put a whole bottle in and keep brushing and backwashing.

[eckardsl]

There is no test that I know of for mustard algae, but I have had it and nothing will get rid of it except polyquat. Get the 60 per cent at Walmart and dump the whole bottle.

[chem geek]

See this post for more info (and the links to other threads mentioned in it). If your CYA level is higher than 50 ppm, then you will likely just want to do a partial drain/refill since battling the algae with high CYA will be very hard and you'll want to lower your CYA level anyway so you might as well do the dilution of water to lower CYA levels first.

Richard

[Sprocket]

tabs

Do you "shock" your pool , or use shock product .

Really not the same thing when you read up more on this bb board .

Get your CYA down to 30 - 40 readings and you'll be a alot happer . Read up on my experiance . Just look for my name using the "search" function .

[matthewnadeau]

I had my water tested and the CYA was 60ppm. Everything else was fine except the alkilinity was a little low. The guy at Leslie's recommended shocking with a non-chlorine shock treatment (Fresh and Clear Chlorine-Free Oxidizer). This is actually what I typically use to "shock" my pool. He didn't seem to thing that Polyquat would do any good. He also suggested increasing my cleaning time to 6 hours.

[heymom1]

How long do you run your filter pump? I've had algae over the last week, got rid of any visible sign of it on Sunday but have been running the pump 24/7 since then. It's not the cleaner that will get rid of algae, it's bleach. Keep your free chlorine levels high - like 10 ppm - and keep brushing every day. After you haven't seen any algae for a week, then clean out your filter cartridges or backwash. If you have a vacuum, I have read many times on this forum that you should "vacuum to waste," whatever that means. I guess it means you vacuum out all the gunk and dump it in someplace away from the pool...

Your CYA level isn't terribly high. Mine is running around 90 right now. When I get back from this summer's trips I am going to take some water out and start using the bleach method.

There's a lot of algae this year, I think it's in the air.

Oh, and you are right about the Polyquat - it's not for treatment of algae, it's for prevention. Ignore that recommendation. Even some pool stores don't sell it to you if you already have algae.

[ChuckD]

Sorry to whomever posted this advice. Poly will prevent the algae, not clear it out.

You need to measure both Combined Cloramines (CC) and Free Clorine (FC). Added together they equal your Total Clorine (TC). When your CC comes down to less than .5 you've eradicated the algae. Stick with just clorine (Chlorox, or the 12.5% you can get at many pool stores) and avoid the other branded "shocking" treatments.

You also need to run your filter 24/7 during this time.
And vacuuming to waste is simply diverting the water sucked up by the vacuum out from the pool system (on to the lawn, or whatever) to save stress on your filter. Some filter systems (like my Hayward EC65) don't have this option.