Ionization system water color experience - need suggestions

[inmanlanier]

I'm new to this forum - wow what a wealth of knowledge. Finally some folks that understand ionization systems. For 2 summers now I've encountered a phenomenon and perhaps you can help.

I have a SuperiorAqua ionization system that I've had since around 1995. We love the low maintenance and low chlorine. PLEASE LET'S NOT GET INTO THE DISCUSSIONS OF HOW I'M AT HEALTH RISK. I have read all the health concerns raised on other posts.

About 18 months ago for the firt time my system started decreasing PH. Prior to then I would always need to add acid periodically to lower PH. We don't swim in the winter so I don't worry about it (I have a fiberglass pool). When I added PH Up last year to get it to comfortable swimming conditions (for the eyes), the pool got very green and cloudy. Throughout the next few weeks of adding too much money's worth of Ultimate Metal Control and Clarifyer, we got the color more or less back and enjoyed the pool the rest of the swimming season.

As I usually do, this past winter I did very little maintenance - we would periodically brush or add some supplemental algaecide/shock to get rid of any algae. 3 days ago I tested, and the PH was very low, so I added PH up. The alkalinity was down around 50 at that time. The pool was beautiful, clear and blue. As I added the PH up the water got immediately green and cloudy. I put in some clarifyer and ran the pump overnight. The next day it was a good bit more clear (still a little cloudy) so I pulled my DE unit apart and totally cleaned it (it was time to do so since I'd not done that in a while - I wanted to get the flowrates up). After that, the water flowed significantly more; I knew I could get good turnover. Then I added 1 bottle of Ultimate Metal Control (@ $20 a bottle). The color improved a good bit (not quite the same blue, but pretty good). The next morning I woke up and trued up the chemistry (I had over added PH up, so back with a little acid, and added alkalinity increaser). With the PH at 7.2 and alkalinity around 130, it looked pretty good. Now I was down on water due to the drought we've had in South Florida and my cleaning of my DE unit, so I added perhaps 5 inches of water to my pool (city water). Here came green again. I then went and added Suncoast's Super Metal Control (a cheaper alternative for iron), and the color didn't immediately change. I added clarifyer and ran the pump a while. Through the night the color has improved a small amount (hard to tell).

I read some other posts that talk about the concern of copper and low PH with ionization systems. Do I just need to keep adding stuff to get the copper back out? What a pain. At this point, I'm clear and slightly green. I'd like to get the blue back.

Please provide suggestions, but also please do so with fact based opinions or experience. Thanks!

[chem geek]

Copper precipitates when the pH rises as copper hydroxide and copper carbonate. The latter can be reduced by having a lower Total Alkalinity (TA). The former can only be reduced by having the pH be lower. Both can be avoided by maintaining a lower level of copper.

The metal sequestrants don't actually physically remove the copper, but bind to it such that it doesn't react with the hydroxide or carbonate, but such compounds do break down over time. Only physical dilution of the water with fill water that is lower in copper will reduce the actual copper concentration.

Also, realize that pH Up is Sodium Carbonate so raises both the pH and also the TA quite a bit. As you have noted, when the TA was low (as well as the pH) the water was clear. So next time you want to raise the pH don't use pH Up. Either use 20 Mule Team Borax (in roughly double the quantity as you would with pH Up) or try aerating the water. Borax will raise the pH with about half the rise in TA and won't add any carbonates to the water. The borates (boric acid in water) from Borax will also act as a pH buffer if you accumulate enough borates over time. Aeration will raise the pH with no rise in TA at all. There are many ways to add aeration to the pool, but one of them is this clever device.

It sounds to me like your copper ionization system is set too high in terms of having too much copper in the water and also that you are using pH Up to raise the pH and end up raising the TA too much as a result.

I'm not sure what posts you've read that have concern for copper and low pH. I don't understand what the problem would be in that case. Low pH below 7.0 can become corrosive to metal, but it shouldn't be a problem for copper in the water. In fact, some chlorine-free systems such as EcoSmarte have high levels of copper and a pH close to 7.0 (I am not promoting such a system -- just using it as an example).

As for having a low chlorine pool, there are other ways to accomplish that without using copper. Bacteria and viruses are fairly easy to kill so only require very low chlorine levels. It's algae that is harder so using an algaecide such as PolyQuat 60 or a phosphate remover would then let you have a lower chlorine level. However, it's not the Free Chlorine (FC) that determines the actual disinfecting and oxidizing (hypochlorous acid) chlorine level but rather the ratio of FC to CYA that approximates this concentration. So you can easily have very low chlorine levels by having a lower FC/CYA ratio while still having enough chlorine "capacity" to oxidize bather waste (urea/ammonia from sweat, mostly) albeit more slowly. So long as you have the algaecide to prevent algae, you could have 1-2 ppm FC with 100 ppm CYA which would be technically equivalent to 0.3 - 0.6 ppm with 30 ppm CYA or 0.01 - 0.02 ppm FC with no CYA which is a very low level of chlorine.

It would be one thing if you wanted a chlorine-free pool and were set on that, but if your focus is on low-chlorine then you really do need to understand how FC and CYA work together. The idea that a higher FC means more exposure to "active" chlorine is just not true. I can tell you from my wife's personal experience that the CYA level makes a huge difference. Her swimsuits degrade in just one winter season of use in an indoor pool that has 2 ppm FC with no CYA in it. In our own outdoor pool during the summer with 3.5 ppm FC and 30 ppm CYA, her swimsuits last for multiple seasons with minimal degradation even after 4+ years. The difference is the factor of 20 difference in "active" chlorine level in these two situations. CYA acts as a chlorine buffer with most of the chlorine held in reserve and inactive so you can easily tune your chlorine concentration by adjusting the FC/CYA ratio.

Richard

[Pool User]

Thanks, Richard

My copper currently is at 0.1 ppm. I'm told by the manufacturer they prefer 0.1 - 0.15 PPM.

The pool has never been drained since installed in 1994. Could it be that it is just an accumulation of solids over the years and we need to drain and refill?

[chem geek]

Mmmmm. 0.1 ppm copper is pretty low and you usually don't see problems at that level unless the pH or TA get pretty high. Perhaps the city water has some metals in it (copper or iron though iron would look more red, not green). So I'm not sure what's going on so hopefully someone can help you out.

[Pool User]

Been a long time since I posted the topic, but....

WOW - this winter I drained my pool then refilled and what a difference. Unfortunately in the process I improperly assessed my groundwater level (that hydrostatic pressure thing), so after repairing the crack in the fiberglass that I incurred I've done essentially rebalanced the pool and DONE NOTHING.

After refilling the pool, I got the basic chemicals into balance. I then superchlorinated since I'm in Florida and the water was stagnant in the pipes for many weeks. Since establishing 3 ppm chlorine 2 weeks ago, I've not added anything and the chemicals are essentially what they were then. Amazing.

Bottom line - my 14 year-old pool water was apparantly supersaturated with who-knows-what and now all is well.

[inmanlanier]

I just noted that the above posts entitled "pool user" are me - so I logged in this time to make sure that all viewing know it's me.

[chem geek]

What was your source of chlorine? If it was stabilized chlorine such as from Trichlor pucks/tabs, then you may have built up a high Cyanuric Acid (CYA) level since for every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases CYA by 6 ppm. A high CYA with a low FC can lead to algae which can make the water turn cloudy, though with your copper in the water I find that surprising since copper usually prevents algae growth. Another possibility is that the high CYA and low FC led to much slower oxidation of organics so that ended up making the water cloudy.

At any rate, a fresh refill got rid of what was making the water cloudy. If you're going to be using Trichlor, you might check on your CYA level every few months. If it's getting high, either dilute the water (backwash more if you have the kind of filter that needs backwashing) or consider using unstabilized chlorine (bleach, chlorinating liquid) at least some of the time.

[kbeau]

My cell for my salt water system has failed and must be replaced to the tune of about $500.00. My wife wants to pursue a "chlorine free" pool, so I have been researching ionization/oxidation, ozone etc. So far the best system looks to be some sort of ionization/oxidation system. What are your opinions of them? Those that have them--are you glad you went that way? Which brand system is the best?

[poolcare]

There is no good alternative to chlorine. The only certified chlorine free chemicals are baquacil and bromine. Baquacil is usually great for a year or two and then the pool becomes impossible to keep balanced as the water mold and filter problems start. Bromine is similar to chlorine and has all the drawbacks that chlorine does.

The other so called chlorine alternatives that use ions or minerals must be used in conjunction with chlorine. Read about copper - silver systems, ionization with oxidation and Pristine Blue.

[biobabe]

I see these 'biopools' are getting more popular. They use no chemicals and rely on plants and sun to keep the water 'clean'. They still look swampy but the water is claimed to be germ-free.

If you want to see some pictures search google for natural swimming pools or swimming ponds.