HTH Algae Guard- Anybody use it?

[3d-aholic]

I've had 3 pools. Lots of experience with Pools. I am a chemist by degree.

My question is pretty simple. Does anyone have any experience with the HTH Algae guard product (3x conc.)? Normally I use a Polyquat based algaecide in addition to chlorine for additional protection. However, this stuff was on sale at Walmart and I thought I would try it.

When I pour it in, it does appear to defeat the algae. However, I see this oily green scum (it looks like algae to me) forming on anything that it can at the top of the water...like my pool thermometer. So first question, is this algae just redeposited in an oil film instead of uniformly across the water. Scares me to think its all collecting on the filter.

Next, if you don't keep adding this stuff, suddenly there is a huge bloom of algae, I don't care what the chlorine level is. Its as if this stuff eventually turns into algae food as one of its decomposition pathways. Once that happens it takes tons of bleach to recover...

I'm trying to determine if my experience is unique or just anecdotal.

[Watermom]

The only algaecide that we recommend is Polyquat 60%. Many of the others create problems such as foaming, etc. By the way, algaecide is a better preventative than it is at killing algae once it starts. At that point, you need chlorine.

[PoolDoc]

3d,

Please read the "Best Guess" page, linked in my sig and Watermom's. Your statement that chlorine won't kill algae, regardless of level is simply wrong.

Once you've read that page, if you want to know more, look at some of Chem_Geek's posts in the "China Shop".

Algae guard is just a plain quaternary ammonia algaecide. They are as a class, irritating, foaming, and unstable in the presence of chlorine. They do kill algae, but there are better ways to do that.

Ben

[CarlD]

Since you are a chemist you should apply your professional expertise to the interactions between chlorine and algae. The idea that chlorine won't kill algae no matter how high the level is simply untrue.

On a Saturday in the middle of May I opened my winter cover and found green slimey water. Algae. I filled the pool up with water from the hose, turned on the pump, then dumped 4 gallons of 12.5% liquid chlorine into my pool. That raised my FC to an estimated 24-25ppm. 24 hours later the water had gone from green to blue, though still cloudy with dead algae. That was less than a month ago.

I have added to my pool this spring:
Bleach/Liquid Chlorine
Dichlor
Trichlor
20 Mule Team Borax (2 boxes)
Arm&Hammer Washing Soda. (1 box)

My pool is clean, my water glistens.
My FC is about 5,
CC 0
TC 5
pH 7.6 (been there for weeks)
TA 60 (in theory too low but with rock-solid pH, I'm not messing with it.)
CYA 30
CH 60

I occasionally add CYA, dry acid OR Muriatic Acid, and PolyQuat.

That's all I use.

Carl

[chem geek]

The chlorine/CYA relationship has been known definitively since at least 1974 as described in this scientific peer-reviewed paper. For more info, I suggest you take a look at the "Chlorine/CYA Relationship" section of this post, look at this thread in The China Shop, and this post on why the FC/CYA ratio is a decent proxy proportional to the hypochlorous acid concentration.

In simplest terms, there is a race between algae growth that is accelerated by nutrient levels (phosphates and nitrates being most limiting), sunlight and temperature and is decelerated by hypochlorous acid and any algaecides that may be present. Regardless of algae nutrient levels, the growth is ultimately limited by sunlight and temperature so there is a hypochlorous acid level that will kill algae faster than it can reproduce without the need for any algaecide. The problem is that the hypochlorous acid level is not just dependent on the Free Chlorine (FC) level and pH, but also on the Cyanuric Acid (CYA) level since most of the chlorine is bound to CYA in a series of compounds called chlorinated isocyanurates that are not strong oxidizers nor disinfectants (i.e. they don't kill algae). So it is critically important to maintain a high enough FC/CYA ratio to be able to kill algae faster than it can reproduce. If you maintain that ratio, then you won't get algae and won't need any supplemental algaecides or phosphate removers to prevent such growth. Ben Powell was first to create the Best Guess Chlorine Chart based on scientific principles and his own experience.

In my own pool through most of my pool ownership I have prevented algae growth using only 12.5% chlorinating liquid with no algaecide, phosphate removers, clarifiers, flocculants or weekly shocking. It costs me around $15 per month for my 16,000 gallon pool, but I have a mostly opaque pool cover that keeps my chlorine usage to around 1 ppm FC per day even though the pool is used every day for 1-2 hours. A similar story (with somewhat higher chlorine demand) is true for literally tens of thousands of pool owners on this and other related websites.

[3d-aholic]

Ok attempting to reask my question better since I didn't really get my question answered...

Is there anybody using HTH Algae Guard (3x conc.) in their pool and what has been your experience with it when using it?

[True Blue]

Ok attempting to reask my question better since I didn't really get my question answered...

Is there anybody using HTH Algae Guard (3x conc.) in their pool and what has been your experience with it when using it?

Yes, I used it when I opened up my pool this year. Bad idea. My pool foamed like crazy. It wasn't until I got the chlorine levels up high enough (using bleach) that my algae problem was solved...(thanks to advice I received in this forum, btw!)

[madwil]

I've heard of it, seen it, never used it personally...
It's ammonia based, which means it "eats" chlorine, increasing chlorine demand with no sanitizing/oxidation effects since all the chlorine is used to breakdown the ammonia, then the chloramines...
In practice, all ammonia based algaecides do this, as well as increasing the opportunity for foaming, greasy films, and follow on algae blooms as people who don't understand what happens to the chlorine fail to get the chlorine levels back to an acceptable level. They add 1lb, or 1 gal, or 3 pucks, because that's what it always takes, and fail to realize how fast that chlorine is absorbed in the ammonia battle without helping the pool- then they think the chlorine is at fault!
I think chem-geek had a post about the amount of chlorine needed to get rid of ammonia- and it is large amounts!
Meaning you have to add that much chlorine, plus enough extra to sanitize/oxidize the algae in the pool!

[waterbear]

Unless Arch Chemical changed their products after buying Applied Biochemists (who did sell Polyquat under several of their brands) they currently only sell copper and linear quat based algaecides in both their HTH and PoolLIfe brands. (I guess they did not want to pay royalties to Buckman Labs since they stopped selling polqyat around 2006.) A few years ago when I was still selling HTH the 60% algaecide was a linear quat and therefore not recommended. Linear quats foam like crazy, sting the eyes, and break down quickly in the presence of chlorine. I assume it is still the same formulation but I have not seen a bottle of it to read the ingredients to see if they have changed but they were (are) :
Alkyl dimethyl benzyl ammonium chloride, 30%
Alkyl ethylbenzyl ammonium chloride, 30%
The remaining parts are inert ingredients, 40%
It seems that Arch Chemical is now following Chemtura's lead in making their MSDS unavailable online.

Hope this answers your question.