Normal Amount of Chlorine / Acid to Use in a Year?

[linen]

The CYA on them does vary somewhat. On the 5 or 6 reports I looked at they ranged from 45 to 60. Is that normal range of variability? It was not necessarily the same person doing each test, so I suspect some differential?

The cya test when done correctly is +/- 15 ppm. I still wouldn't totally trust their numbers, and your level should be going up as you add more pucks. I would recommend not adding anymore since 50 ppm is the upper limit of our recommend range.

Taylor is a good brand, but that does not ensure good results. We advocate that pool owners do their own testings, which has shown to result in more accurate and consistent results. See: http://www.troublefreepool.com/pool-school/pool_test_kit_comparison...both kits use Taylor reagents, but the TF-100 has more of what is typically needed and ends up being more cost effective.

 

[LarryFlorida]

Do you have the ability to measure cya? If your cya is high (which I suspect it is due to your puck use), then 3 ppm FC is not very much.

I saw the CYA and chlorine table on this site.

So, if my CYA is actually ~50, then the target chlorine is 6 ppm with a 4 ppm minimum according to the table.

It appears that I run below the target (I dont recall ever reading 6 ppm, but my basic kit probably wouldnt be able to tell anyway), although it may spike there sometimes if I dump in some liquid. As I dont seem to be having water quality issues, maybe the ozone is actually doing something?

 

[jblizzle]

Maybe ... for now ...

 

[LarryFlorida]

The CYA on them does vary somewhat. On the 5 or 6 reports I looked at they ranged from 45 to 60. Is that normal range of variability? It was not necessarily the same person doing each test, so I suspect some differential?

The cya test when done correctly is +/- 15 ppm. I still wouldn't totally trust their numbers, and your level should be going up as you add more pucks. I would recommend not adding anymore since 50 ppm is the upper limit of our recommend range.

That brings up a related question.......

The typical pool owner around here seems to just use the tablets ("pucks") in an inline dispenser as the means to add chlorine. Where does all the CYA "go"? Wouldnt the CYA eventually read some astronomical value and the chlorine wouldnt "work" anymore?

My parents pool has been using the chlorine pucks for what must be two decades. I know my father tests the water regularly, so I wonder what his CYA reading is? It must be so high as to be unmeasureable?

 

[LarryFlorida]

Maybe ... for now ...

If nothing else, Ive got some shiny "eye candy" hanging on the wall near the pool pumps! LOL

 

[LarryFlorida]

I appreciate all the fielding of my "novice" questions BTW!

 

[linen]

I appreciate all the fielding of my "novice" questions BTW!

We were all there once...I am not far from it now.

The typical pool owner around here seems to just use the tablets ("pucks") in an inline dispenser as the means to add chlorine. Where does all the CYA "go"? Wouldnt the CYA eventually read some astronomical value and the chlorine wouldnt "work" anymore?

Great question. The cya doesn't go anywhere and eventually these pools typically get partially drained and refilled. This might be partially mitigated by the ton of rain that some of you Floridians get if the pool overflows a ton.

 

[Smykowski]

The typical pool owner around here seems to just use the tablets ("pucks") in an inline dispenser as the means to add chlorine. Where does all the CYA "go"? Wouldnt the CYA eventually read some astronomical value and the chlorine wouldnt "work" anymore?

Bingo. This is exactly why we chlorinate with either liquid bleach or a SWG system. Pucks are for hockey players (and maybe the occasional vacation :grin: ).

 

[LarryFlorida]

The typical pool owner around here seems to just use the tablets ("pucks") in an inline dispenser as the means to add chlorine. Where does all the CYA "go"? Wouldnt the CYA eventually read some astronomical value and the chlorine wouldnt "work" anymore?

Bingo. This is exactly why we chlorinate with either liquid bleach or a SWG system. Pucks are for hockey players (and maybe the occasional vacation :grin: ).

Something doesnt make sense tho to my newbie, but logical, mind......

If 99% of the people out there just throw the pucks in a dispenser and do this ad infinitum, and consequently run their stabilizer values through the roof, then why arent all their pools green because they arent running some huge amount of chlorine? I ask this honestly, not be be a wise @$$!

 

[linen]

If 99% of the people out there just throw the pucks in a dispenser and do this ad infinitum, and consequently run their stabilizer values through the roof, then why arent all their pools green because they arent running some huge amount of chlorine? I ask this honestly, not be be a wise @$$!

Well that is where some pool stores really make their money...phosphate removers, algaecides, etc....but eventually there is a drain/refill.

 

[jblizzle]

One possibility is that they also throw bags of "shock" into the pool on a weekly basis. This will temporarily raise the FC and hopefully keep the algae at bay. If they use cal-hypo bags, that will add calcium. If they use dichlor bags, that will add CYA and make the problem possibly worse.

Another possibility is the use of an algaecide, that may reduce the likelihood of algae starting even with low FC.

The pucks can work fine if you have a short season and drain in the winter OR you replace a LOT of water through the year ... possibly rain due to rain in your case.

Come and check the forum in Aug/Sept when there are suddenly a bunch of new posts saying, my pool has been great all year and suddenly it is green ... well, the CYA built up too much and the FC was not enough. It can work for awhile, but eventually may catch up with them.

Curious to know what all 99% of the people are REALLY spending on chemicals and adding to their pools.

 

[LarryFlorida]

Curious to know what all 99% of the people are REALLY spending on chemicals and adding to their pools.

That is the real root of my original question!

My desire is, like everyone else, to spend the bare minimum on pool chemicals, but also have water that is enjoyable. (To me, this means to not smell like chemicals, and to not turn my daughters blonde hair green).

My shot at ozone was an attempt as some combination of these somewhat mutually exclusive desires.

My chemical costs for the past 14 months I guess I now consider very low for a pool that is in use year round (in that Ive spent ~$75 on chlorine tabs, ~$15 on liquid chlorine, and Im not sure what on acid (I cant recall what each jug costs, but Ive used ~6). I think they might be $5-6 a jug? I suspect I can safely say Ive spent something less than $150 in 14 months on chemicals.

From what Ive seen poking around the board, these costs seem quite low compared to what others typically spend?

But, of course, I had to spend the up front $ on the ozone, which others have not spent. I honestly dont recall their exact costs, but I want to say the big unit was ~$450 and the small one ~$200.

I am starting to actually think the ozone does reduce the chlorine demand notably the more I look around and see what others are spending on chemicals (even the el cheapo approach of buying bleach jugs, etc).

I am also starting to think I sound like an ozone salesman! LOL Any sort of science aside, anecdotally (and as much as its human nature to want to justify our decisions, purchases, etc) it just doesnt seem logical that I am not using more chlorine for a pool of this size thats used year round and that sits at a relatively warm temperature most of the year?

 

[chem geek]

Most chlorine loss in an outdoor pool is from breakdown from the UV in sunlight and ozone does nothing at all to stop that. Ozone does react with chlorine, but odds are your ozonator is too small to have a noticeable effect. Where one normally sees the effect of ozone is in a spa, but you won't see that unless you only circulate the spa water.

I spend around $15 per month for chlorine and a few dollars a month (averaged) for some acid for my 16,000 gallon pool, but I have a mostly opaque pool cover so even with daily use my chlorine usage is lower at 1 ppm FC per day. So figure for a 20,000 gallon pool and a 2 ppm FC per day chlorine usage from lots of sun that's around $38 per month except chlorine is probably less expensive in Florida -- perhaps it'll be more like $30 per month.

So it does sound like your costs are a lot less, probably because your chlorine level is lower and you've been lucky not to get algae. Some pools are naturally low in phosphates so will be less likely to get algae unless the chlorine gets much lower. The FC/CYA levels we recommend are such that they prevent green and black algae growth regardless of phosphate level.

It's up to you if you want to let the FC/CYA ratio get lower than recommended and if you run into problems with algae you can then shock and possibly do a partial drain/refill if your CYA gets high. That's the most common scenario for many new members who come to the forum with algae, but most then follow the recommendations and don't get algae again. Some of these pools have had ozonators so we know it's not a panacea.

 

[LarryFlorida]

Most chlorine loss in an outdoor pool is from breakdown from the UV in sunlight and ozone does nothing at all to stop that. Ozone does react with chlorine, but odds are your ozonator is too small to have a noticeable effect. Where one normally sees the effect of ozone is in a spa, but you won't see that unless you only circulate the spa water..

This is the ozone unit I have on the pool. They claim 1 g/hr of ozone at 1350 ppm. Of course I have no way to verify this and Im not sure if this is too small to have an effect? They state its good for 25,000 as primary sanitizer and 100,000 gallons as secondary. They show a price of almost $1100! I did not pay anything close to that.

http://shop.delozone.com/p/ec-4-16-120v ... tely?pp=12

I have this unit on the spa....same thing just with 1 cell instead of 4. I believe this unit is overkill for the spa as the pump turns the water over in the spa probably 10 times an hour and runs 6+ hours a day, so the water gets "zapped" many times with the ozone.

http://shop.delozone.com/p/ec-1-26-240v ... tely?pp=12

 

[LarryFlorida]

Some pools are naturally low in phosphates so will be less likely to get algae unless the chlorine gets much lower.

That reminded me that I did get my pool water tested for phosphates (as the Leslies nearby does it for free as part of the regular test). I recall the value moved around, but was generally 300-500 ppm range (with one reading upto 1000 one time....I just found some test sheets) . Is that considered low? I thought I recalled them saying this level can bounce around with rain, etc.

 

[LarryFlorida]

if you run into problems with algae you can then shock and possibly do a partial drain/refill if your CYA gets high.

Is algae the basic "proxy" for whether or not the pool is being sanitized sufficiently?

 

[257WbyMag]

Algae or cloudy water is what most folks notice when they first detect a problem. For most of us here, we see problems such as an increase in chlorine consumption over normals or a bump above 0.5 ppm CC.

 

[chem geek]

Is algae the basic "proxy" for whether or not the pool is being sanitized sufficiently?

No, it's not, though algae are harder to kill than most common bacteria, including fecal bacteria. The problem is that they use some different nutrients and of course algae require light to grow while most bacteria do not (cyanobacteria being the exception). Note that bacteria grow 3-32 times faster than algae. Hot tubs, for example, can get serious bacterial growth but usually don't get algae because they are covered (so no light) and are at hot temperatures (algae don't generally like 104ºF).

300-500 ppb is enough to get some algae, though not growing as quickly as at 1000+ ppb. Generally, at 100 ppb or lower, algae growth gets very slow and at that level it's like having a strong algaecide in the pool. You could still get algae with no chlorine in the pool, but it would be somewhat self-limiting as it used up the remaining nutrients.

Since you actually smelled ozone coming out of the returns before you re-plumbed, it does sound like your ozonator is on the stronger side and not undersized. So it's possible that some residual ozone is making it into the pool and might be keeping algae at bay, especially since you are chlorinating so only some extra assistance is needed. It's a good thing you re-plumbed since you don't want to be smelling ozone. The threshold for smell is not that far below the threshold for being a long-term health problem which the EPA sets at 70 ppb in air.

On this forum we keep things simple by adding only that which is needed and since chlorine provides both oxidation and disinfection, we don't recommend anything else such as algaecides, phosphate removers, clarifiers, flocculants, enzymes, ozone, UV or weekly shocking -- at least for outdoor pools exposed to sunlight. When the chlorine breaks down from the UV in sunlight it produces powerful hydroxyl radicals which is what some of the ozone does when it breaks down as well (eventually these become oxygen gas via hydrogen peroxide if they don't react with anything). So you're on your own, but keep us up-to-date on how things are going since we do track these sorts of things.

 

[LarryFlorida]

So you're on your own, but keep us up-to-date on how things are going since we do track these sorts of things.

Will do.

Not to be contrary to the general advice of this board (which I do appreciate), but I think I will just keep doing what I have been doing. It seems to be working and I do enjoy not having that chlorine smell that most pools have.

 

[jblizzle]

Fyi: The chlorine smell is due to high CC (the bad stuff) and generally a sign of not enough FC in the water.