Starting to see some algae in indoor bromine pool

[JPMorgan]

I have recently noticed small amounts of algae at the bottom of an indoor bromine pool. This is an association pool which I help to maintain. The pool company says they add algaecide, clarifier, phosphate remover and shock weekly. They shock the pool using potassium monopersulfate. All these chemicals seem unnecessary to me (following TFP protocols). Can I just use liquid chlorine to shock the pool and will that effectively address the algae issue?

Would there be any issue with people entering the pool shortly after shocking (with the high sanitizer level). Pool is clear other than the small amounts of algae I'm noticing in the corners of the pool.
Thanks for any help you can provide.

 

[Texas Splash]

Can I just use liquid chlorine to shock the pool and will that effectively address the algae issue?

We can ask @JoyfulNoise, to be sure, but I doubt it. Being a bromine pool, and knowing several chemical cocktails are used regularly in that pool, chlorine may not be much of a factor.

 

[JoyfulNoise]

When you add chlorine to a bromine pool it simply oxidizes the spent bromide ion to active bromine. You are shocking the pool but it’s bromine that’s doing the work not chlorine. You can add chlorine to the pool but you must not shock higher than a reading of 20ppm on the bromine scale.

No, people can not swim in a hyper-brominated pool. Unlike a chlorine pool that has CYA stabilizer to helps moderate the active chlorine levels, a shocked bromine pool would have so much free bromine in it as to make people feel sick. They must stay out until the bromine levels drop to 6-8 range.

The SLAM process can somewhat be applied to a bromine pool as well. You simply raise and hold the bromine levels between 16-20ppm and then brush and wait for the pool to clear up. once the bromine seems to be holding, then you can let it return to normal. But no one can use the pool until it does.

Non-chlorine shock is useless against algae. It’s an oxidizer not a sanitizer. MPS is only used to help deal with bather waste. A polyquat-60 algaecide is fine to use in a bromine pool but it’s basically just insurance in case bromine levels drop a little low. Once algae is present, algaecides are useless. Stay away from flocs, clarifiers and phosphate removers as they are more trouble than they are worth and do nothing to stop algae in an indoor pool.

 

[JPMorgan]

Thank you so much.... very helpful. Not sure what caused the algae because there is an automatic feeder and bromine level has been holding steady at around 4 ppm. The pool does get some sunlight through large glass windows along one side of the pool. Could that be an issue? I will try the polyquat-60 and also maybe bump up the bromine to around 6 level. Thanks again.

 

[JoyfulNoise]

Thank you so much.... very helpful. Not sure what caused the algae because there is an automatic feeder and bromine level has been holding steady at around 4 ppm. The pool does get some sunlight through large glass windows along one side of the pool. Could that be an issue? I will try the polyquat-60 and also maybe bump up the bromine to around 6 level. Thanks again.

4ppm Br is probably not enough in a community pool. With enough bathers splashing around (and probably using the pool as their personal urinals), that 4ppm can easily get used up causing there to be minimal sanitizer against algae and the pathogens. Algae is somewhat rare in an indoor pool as it has to be dragged in from outside to inoculate the pool water. But, if people are using swim clothes for both the community pool and other outdoor recreational water bodies, then it's not out of the realm of possibility to drag it in.

Adding an algaecide is not going to get rid of algae that has already started to grow. You'll need to raise the bromine levels and scrub really well until there is no sign of the algae. The good news is that bromine is very effective against algae so it really shouldn't take much if the algae is only in a small area. You can try elevating to 10ppm with heavy brushing and mixing and then see how the pool progresses. It's easier if you can simply shut the doors to bathers for a day or two while you try to correct the issue.

 

[JPMorgan]

4ppm Br is probably not enough in a community pool.

Actually, the pool doesn't seem to get much use. I rarely see people using it (which seems strange to me), but there are quite a few "seniors" living in this complex.
Re: shocking... you mentioned raising bromine to 20 ppm in your first reply and 10 ppm in your second reply. Should I start with 10 ppm and take it higher if necessary? Also... How do I know how much liquid chlorine to add to raise bromine to the appropriate level? Pool Math only calculates for FC, so would I enter 5 ppm as my FC Target if I want to get 10 ppm of bromine?

 

[JoyfulNoise]

Actually, the pool doesn't seem to get much use. I rarely see people using it (which seems strange to me), but there are quite a few "seniors" living in this complex.
Re: shocking... you mentioned raising bromine to 20 ppm in your first reply and 10 ppm in your second reply. Should I start with 10 ppm and take it higher if necessary? Also... How do I know how much liquid chlorine to add to raise bromine to the appropriate level? Pool Math only calculates for FC, so would I enter 5 ppm as my FC Target if I want to get 10 ppm of bromine?

You can start with 10ppm and see if it works. 20ppm is sort of the max bromine level that you’d ever want to go to. In fact, because this is a community pool, state health dept regulations are in effect and you need to make sure that you are following their guidelines as well. Some health departments will set max permissible levels on sanitizers as well as levels that are considered “safe to swim” in.

 

[JPMorgan]

Don't think I got an answer to one of my questions in my last post.... "How do I know how much liquid chlorine to add to raise bromine to the appropriate level, i.e., 10ppm? Pool Math only calculates for FC, so would I enter 5 ppm as my FC Target if I want to get to 10 ppm of bromine?

Also, I'm assuming it's preferable to use liquid chlorine to shock a bromine pool rather than MPS. Is that correct? We have a lot of MPS on hand, but I'd like to know if it's advisable to use it... or not.

Thanks for all your help.