How to add Borax

[smallpooldad]

Chem Geek,

Thank you for the response.

The CYA was 55, and by accident I got the chlorine at that time to 40 ppm but did not hold it there.

What would be the best course of action now? Take chlorine up to 45 ppm and hold it there for how many days?

Hope this helps.

Aloha

[chem geek]

The CYA was 55, and by accident I got the chlorine at that time to 40 ppm but did not hold it there.

What would be the best course of action now? Take chlorine up to 45 ppm and hold it there for how many days?

Well, assuming that what you have is this yellow/mustard algae, and that's a big assumption, with a CYA of 55 I think holding an FC level of 40 ppm should be enough but it will take a few days or possibly a week to get rid of this stuff. It seems that most people who finally decided to use such high levels of chlorine did start to see a reduction in the algae after a couple of days and then full clearing usually within a week. For those that took longer, I am not sure if it's because they didn't have a high enough chlorine level, but suspect that is the case.

It seems that to get rid of the yellow/mustard algae that the actual disinfecting chlorine level needs to be at least 1.0 ppm which corresponds to around 2 ppm FC if there were no CYA present. The 55 ppm CYA level requires somewhat less than 40 ppm of FC to achieve this 1.0 ppm disinfecting chlorine level.

Given the reduction you are already seeing due to the Borates, I suspect that after final removal of this algae infestation, if that is what it is, you won't see it come back due to the Borates. At least that is the hope. With several users now using Borates, we'll see if any get the mustard/yellow algae bloom next year. We won't really know for sure until enough users, especially those that typically get the mustard/yellow algae, use 50 ppm Borates.

Richard

[smallpooldad]

Chem Geek,

Thank you for the reply. Lots of questions follow.

Firstly something odd is happening. The stains are slowly going away but the usage of Chlorine is going up 2 1/2 ppm loss to 4 ppm now, at a maintenance level of 8 ppm. Could this be due to the fact that the algae is now exposed and chlorine is being used up in the killing process? My concern is that I do not have a borate test kit, do you think that this level as well could be getting used up? I will order on-line this test kit.

I will boost the Chlorine to 40 ppm and hold it there for one week.

Could I use United Chemical's Yellow Treat which contains 88.8% Sodium Bromide, to aid in the destruction of this algae, or is this a bad idea?

I understand that Bromide consumes large quantities of Chlorine but seems to be effective in treating mustard algae. Any idea on how much Chlorine might be used up over the week so I can stock up? And should I maintainance the level back to 40 as it is used up? Is it correct that the filter need to be going 24/7 for the entire process?

What level of nitrates are considered bad for a pool?

Lastly I have Great White 9500 Pool Cleaner that has brushes on it that sweeps the pool is this good enough to do the brushing that is required or would it be better to hand brush with a pole? If so how often, and are the nylon brushes good enough or do I need to get stainless steel brushes?

Looking forward to your reply.

Aloha

[chem geek]

Could I use United Chemical's Yellow Treat which contains 88.8% Sodium Bromide, to aid in the destruction of this algae, or is this a bad idea?

I understand that Bromide consumes large quantities of Chlorine but seems to be effective in treating mustard algae. Any idea on how much Chlorine might be used up over the week so I can stock up? And should I maintainance the level back to 40 as it is used up? Is it correct that the filter need to be going 24/7 for the entire process?

What level of nitrates are considered bad for a pool?

Lastly I have Great White 9500 Pool Cleaner that has brushes on it that sweeps the pool is this good enough to do the brushing that is required or would it be better to hand brush with a pole? If so how often, and are the nylon brushes good enough or do I need to get stainless steel brushes?

I would not use Yellow Treat or anything else other than Chlorine, at least initially. There are other threads in the Algae section that pretty much say everything is useless or certainly no more effective than chlorine except possibly PolyQuat 60% which is mostly for algae prevention and not elimination.

As you point out, Bromide gets activated to Bromine by Chlorine and is generally what is done in spas that use bromine. This is not something you want to do in pools. Once you've got the bromine in your pool, it will be hell to get it out as the chlorine will reactivate it -- so you will end up in a cycle of bromine disinfection, then chlorine reactivating it, with the net result that bromine will be doing some of the work from chlorine, BUT doesn't do as good a job (generally) which is why it takes more bromine to be as effective as chlorine. Bottom line, don't add bromine to your pool in any form (bromide or bromine). Note that Borates refer to Boron which is a completely different element than Bromine -- confusing, eh?

Yes, maintain the level of chlorine at 40 ppm as it gets used up. If your pool is exposed to strong sunlight, then it could use up to half the chlorine during the day so that would be 20 ppm, but the key to see if this is working is to see if it gets used up at night and if the algae appears to diminish. You could just get enough chlorine for a few days (60 ppm worth) and then see how your usage goes.

No idea on what level of nitrates is bad. I know that it's food for algae, but don't know what level starts to trigger significant algae. Perhaps someone else knows that.

Unless you have black algae, you shouldn't need anything more than nylon brushes. Perhaps before you get started too much on this, you should make sure you don't have black algae. Black algae will be deeply embedded into the plaster surface while mustard/yellow algae will be more like a powder. If you have black algae, then the high chlorine level is less important that continually brushing and knocking off the exposed heads of the algae. Some people scrape the black algae with a Tri-Chlor tablet since this is both acidic and high chlorine (though bound to CYA so I somewhat question that) that black algae does not like. I think your overall high chlorine level plus scraping should be fine, even if this is black algae.

Since you seem fairly certain that whatever you have is algae, you should probably post in the Algae section and have Marie comment since she is the expert in that area. You can link to your post in this thread as a reference. She can probably refer you to pictures or ask you questions to identify exactly what it is that you have and how to treat it.

Richard

[smallpooldad]

Chem Geek,

Once again thank you. I will do as you suggest and report back the results.

Aloha

[waterbear]

I

No idea on what level of nitrates is bad. I know that it's food for algae, but don't know what level starts to trigger significant algae. Perhaps someone else knows that.


Richard

From what I have been able to find out it seems to be between 10-25 ppm but I don't know if that is as nitrate nitrogen or nitrate ion which is approx. 4.4 times higher than the nitrate nitrogen reading. I suspect it is the nitrate nitrogen reading since this is the way it is most commenly expressed in water quality measurements. The EPA has set the safe limit of nitrates in drinking water at 10 ppm nitrate nitrogen (44 ppm nitrate ion). Some sources state that superchlorination (well above breakpoint, in ther neightborhood of 50 ppm and often much higher) often effectively deals with high levels of nitrates and nitrites in the water. Others say that there is no way to reduce high nitrate levels besides a drain and refill with low nitrate water.
When nitrates are present in the water nitrites are often present too and the effect of both are cumulative in terms of algae growth. Nitrites are tested more rarely than nitrates in pools.