Pool Chemistry Questions and Direction

[wil]

Moved to a house 2 months ago that has a pool and am stocked about being a new pool owner.

Really appreciate your site as I've learned a ton already and ya'll are honest and have the consumers best interest in mind.

I think a lot of people (including me) new to pool ownership initially are vigilant towards chlorine because there is a fear factor about its adverse effects on health based on articles and things heard here and there. I’m a bit of a health freak myself and ovoid as much bad chemicals as possible. However, after countless hours of reading and research to get to a bottom line, I think I have a reasonable grasp on a philosophy towards pool ownership and the use of chlorine. Exposure to chlorine in small amount for short periods of time (2-3 hours or so) out way the risks of other systems that claim chemical independence or chlorine free methods. My tap water comes in at .5ppm and the EPA approves drinking water up to 4ppm of chlorine. (Although I’m planning on installing a filter to clear out chlorine and other additives)

Bare with me here as I’m leading to some questions. Just would like to first establish the above that I’m in support of using chlorine. :blah:

So I’m convinced that systems claiming chemical or chlorine free methods are not the way to go however, I would like to invest and/or set up a system that could minimize the adding of chemicals and was hoping you guys as experts could guide me through this with helping me understand a few things and maybe recommend some options.

Knowing that FC is dependent on CYA, is it possible to maintain a consistent 1ppm chlorine level and is there a system (maybe SWCG) that could help with this?
(The Del Ozone claims to be able to do this although I’ve had some feedback it would be a waste of money)
Is CYA a potential health hazard in pools and if so, is it better to not use a SWCG system since it requires higher levels of CYA?
What is safer to one’s health muriatic acid vs borax?

As a non-competent chemistry student, it’s strange to poor bleach into the pool as opposed to purchasing specific pool chlorine but based on my reading of the BBB methodology, bleach consists of a more basic form of chlorine with less additives. So does this mean bleach is better for one’s health than pool specific chlorine?

Thanks again for your communal commitment to provide honest feedback.

 

[RobbieH]

With a SWG, you can maintain your pool at 4ppm, which is within the EPA guidelines you stated. 1ppm is not going to keep your pool sanitary. I would hope you would rather have a little chlorine in the pool rather than a lot of microbes?

Ozone is only beneficial to indoor pools. They assist in the breakdown of chloramines. On an outdoor pool, you have the sun for this.

CYA is not a concern. The higher CYA is so you can maintain FC with the SWG without overworking the SWG.

Muriatic acid and borax are used for two different things. Muriatic acid is simply a weak solution of hydrochloric acid, used for lowering pH.

Bleach and liquid pool chlorine are exactly the same thing. In most cases, the pool chlorine is a stronger concentration. Solid forms of chlorine sold by pool supply houses contain other additives which will build up in your pool, and can only be removed by draining and refilling some or all of your pool's water.

 

[RobbieH]

In addition, I want to mention that most people complain about bleach either being smelly or it causing stinging eyes or other symptoms when the cause is actually not due to high FC levels. High CC levels will cause these symptoms, and CCs should not be high unless there is some sort of problem with the pool chemistry.

 

[wil]

Ahh my fault. Just reread the BBB section, Borax is to raise PH and Muriatic acid to lower PH.

Please tell me if I am wrong but I believe I read somewhere (maybe on EPA site) that 1ppm of chlorine is enough to fight off microbes in a non-closed water system.
Is the reason 1ppm of chlorine can not keep the pool sanitary because the FC will get used up in fighting microbes and the 1ppm will drop below levels that can cause outbreaks?

 

[Leebo]

The FC of 1ppm suggestion could be assuming there is zero CYA in the water.

 

[RobbieH]

There are two things you need to keep in mind though:
1. 1ppm might be enough with zero CYA, AND
2. That EPA standard probably doesn't take into account people bathing in the water and possibly doing other things (peeing?) in the water. You will also have all sorts of other organics entering the water such as leaves, bugs, and yes even dead animals sometimes. I've pulled dead lizards, mice, and toads out of mine. I've even pulled duck eggs out of the pool. And yes, the ducks did their other business in the pool too.

When there are organics in the pool, the FC is used and creates the CCs (chloramines). The sun will burn off the CCs. So yes, it's very easy to go under 1ppm. I would think it would be extremely difficult to maintain 1ppm in a pool. I keep mine around 5ppm to ensure I never drop under 3.

 

[jblizzle]

As mentioned above (and I mentioned in your other thread), the CYA serves 2 purposes: 1. Protect the FC from the sun and 2. Buffer the active chlorine level.

1ppm of FC would keep the pool safe if your CYA was 0ppm (meaning you have NO protection of the FC from the sun). But, when the CYA is 0ppm, in the afternoon, you will lose 50% of your FC to the sun every hour. So that 1ppm will almost disappear in a matter of hours unless you are continuously adding a lot of chlorine to maintain it.

When you add the CYA, you lose less to the sun AND the water is much more gentle on bathers' skin/hair because the CYA buffers it. So, with higher CYA levels, you actually need to add LESS chlorine to the water everyday because it is not lost to the sun.

With a SWG system, the chlorine is added while the pump is running, but at a slow rate. Thus, the higher CYA levels are recommended so the FC is not lost to the sun as soon as it is added to the water ... this also lets the SWG not need to generate as much and thus the cell should last longer.

BTW, there is some posts about adding borates (borax) to the water which point out that it can be dangerous if you have dogs that drink a lot of the pool water. As such, I would view adding the borates (which I don't think you are talking about doing) as more potentially more "harmful" than following the recommended CYA and FC levels.

 

[wil]

I see. My pool is in the sun for most of the day so CYA would have to be added to keep FC levels acceptable to fight off microbes.
I've had a few mice in my pool, one dead one, just in the last 2 months. Thanks again for all the advice and guidance. Very educational and helpful.

 

[jblizzle]

Dead animals are more common than you might think. Generally they do not cause any required change to maintenance if the normal FC levels are maintained.

 

[RobbieH]

if the normal FC levels are maintained.

That's the key statement.

 

[chem geek]

You need to understand that the FC level alone means nothing in terms of chlorine's strength when CYA is present. CYA significantly moderates chlorine's strength where the minimum FC level for a manually dosed pool is roughly equivalent to an FC of only 0.07 ppm with no CYA and in an SWG pool the minimum FC level is roughly equivalent to an FC of only 0.05 ppm with no CYA. When CYA is present, you need to look at the FC/CYA ratio, not FC alone.

In other words, compared to chlorinated drinking water at 1 ppm FC with no CYA, your pool water has over 10 times lower active chlorine level and reacts with skin, hair, swimsuits, etc. over 10 times more slowly.

 

[wil]

ok, I'm embarrassed to say, you totally lost me there on that last post.

So you're saying that because CYA is present in the water that keeps chlorine levels to around 3-5 ppm, it actually has less effect on us than 1ppm of chlorine in drinking water?

 

[Leebo]

ok, I'm embarrassed to say, you totally lost me there on that last post.

I understand what he's talking about...... And he still always loses me.

 

[duraleigh]

CYA "buffers" the effects of chlorine greatly. Referring to the examples chemgeek gave above, it is pretty easy to see that chlorine buffered with CYA is no where near as aggressive than chlorine with no CYA.

Maintaining a 1 or .5 ppm of chlorine in your pool is almost a practical impossibility.

maintaining a 5-7 ppm chlorine in your pool with 40 CYA is easy to manage and it is less aggressive than the unbuffered .05 - 1 ppm

 

[jblizzle]

I think part of the confusion is that the FC is still in the pool at the higher levels, but buffered so not as aggressive to skin and hair. We are talking about comparisons of bathing/swimming in the water ... not the EPA rules for drinking water. Certainly should not be drinking pool water.

 

[chem geek]

So you're saying that because CYA is present in the water that keeps chlorine levels to around 3-5 ppm, it actually has less effect on us than 1ppm of chlorine in drinking water?

Yes. Less than 1/10th the effect.

 

[wil]

ok thanks for the explanation . that makes sense