Purple algae?

[wileyt]

I in the last month I have a purple film on the wall of my pool. I thought it was algae but now I'm not so sure. The water is clear. The chlorine level and ph levels appear to be normal. I have tried algicide and increasing the chlorine level. I have bushed it off only to have it come right back. Is this possibly bacteria? Any help would be appreciated.

[muss08]

Get your water tested for manganese. Manganese leaves purple stains and residue

[KH]

I in the last month I have a purple film on the wall of my pool. I thought it was algae but now I'm not so sure. The water is clear. The chlorine level and ph levels appear to be normal. I have tried algicide and increasing the chlorine level. I have bushed it off only to have it come right back. Is this possibly bacteria? Any help would be appreciated.

See here ask alan a question com/pool_stain_problems.htm for a possible solution.

[Guest]

Could be overuse of a copper-based algicide.

[srlewis76]

I have the same issue, it's not covering the whole pool but there are several spots. I am also reading no chlorine. I am using an auto chlorinator and know it is producing more than enough chlorine for the pool. What causes the purple on the liner and what would cause it to show no chlorine?

[chem geek]

If you are using an auto chlorinator, then it sounds like you are using Trichlor pucks/tabs. This can build up Cyanuric Acid (CYA) unless you are diluting a lot of water. If you are also using copper-based algicide or if the Trichlor pucks you are using have copper in them (some do), then the purple could be copper cyanurate which has an amethyst color.

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm. So even with a low 1 ppm FC per day chlorine usage, continued use of Trichlor pucks/tabs will increase CYA by over 100 ppm in 6 months if there is no water dilution.

Read the Pool School to learn more about how to maintain your pool and the chlorine/CYA relationship.

[nocturnalsheep]

I have the same issue, it's not covering the whole pool but there are several spots. I am also reading no chlorine. I am using an auto chlorinator and know it is producing more than enough chlorine for the pool. What causes the purple on the liner and what would cause it to show no chlorine?

Obviously your chlorinator is not producing enough chlorine, because otherwise your free chlorine wouldn't be 0. Tablets are usually decent for maintenance use, but they won't always be able to keep up with the chlorine demand in your pool. Also, if a high amount of organic compounds get into your pool and overwhelm your chlorine (turning it to chloramines), then your tablets will only cause more problems for you by creating more chloramines. It's usually a good idea to use a granular chlorine as well to boost the levels when necessary as well as using non-chlorine shock on a regular basis to oxidize out organic compounds.

Also, is the kit/strips you are testing with test for only free chlorine or free and total chlorine? If it just tests for free chlorine, then there is the possibility that your chlorine is being overwhelmed and all you end up with are chloramines. Your pH also plays a role in this issue. If it is low, then your chlorine is going to disappear a lot faster. If you have been using tablets for awhile and haven't balanced the pH then this could definately be the case because tablets are very acidic and will affect the pH of your water over time.

So to answer your question "what would cause it to show no chlorine?"; the fact that you have no chlorine would cause it to show that (at least no free chlorine). Tablets are not magic and will not always be the answer.

-Danny

"the pool whisperer"

[Biased Coug]

So how do we get rid of the purple color? I've stopped the copper based algeacide, but I still have the purple color.

[Biased Coug]

I have the same issue, it's not covering the whole pool but there are several spots. I am also reading no chlorine. I am using an auto chlorinator and know it is producing more than enough chlorine for the pool. What causes the purple on the liner and what would cause it to show no chlorine?

Obviously your chlorinator is not producing enough chlorine, because otherwise your free chlorine wouldn't be 0. Tablets are usually decent for maintenance use, but they won't always be able to keep up with the chlorine demand in your pool. Also, if a high amount of organic compounds get into your pool and overwhelm your chlorine (turning it to chloramines), then your tablets will only cause more problems for you by creating more chloramines. It's usually a good idea to use a granular chlorine as well to boost the levels when necessary as well as using non-chlorine shock on a regular basis to oxidize out organic compounds.

Also, is the kit/strips you are testing with test for only free chlorine or free and total chlorine? If it just tests for free chlorine, then there is the possibility that your chlorine is being overwhelmed and all you end up with are chloramines. Your pH also plays a role in this issue. If it is low, then your chlorine is going to disappear a lot faster. If you have been using tablets for awhile and haven't balanced the pH then this could definately be the case because tablets are very acidic and will affect the pH of your water over time.

So to answer your question "what would cause it to show no chlorine?"; the fact that you have no chlorine would cause it to show that (at least no free chlorine). Tablets are not magic and will not always be the answer.

-Danny

"the pool whisperer"

So how do we get rid of the purple color? I've stopped the copper based algeacide, but I still have the purple color.

[Gueat]

I use removit and staintrine to get rid of purple stains. I see it only in vinyl liners, and it usually happens after opening a pool and having to shock it hard. I've never seen it in a plaster pool.