High CYA Levels, Shocking, Yellow/Mustard Algae

[chem geek]

WARNING: This post is bound to be controversial.

I know that we generally tell people to shock their pools with chlorine if they have algae and we tell them to dilute the water to lower high Cyanuric Acid (CYA) levels first before doing such shocking. However, there are some cases where there might be more expedient approaches that would be worthwhile. Specifically, if one gets yellow/mustard algae then higher CYA levels make the required chlorine levels quite high for getting rid of such algae. If one has a saltwater chlorine generator (SWG) pool where a higher CYA level is usually recommended or if one is in a very sunny area without a pool cover and has a higher CYA level to reduce chlorine loss, then fighting yellow/mustard algae with chlorine alone can become impractical or certainly cumbersome and no longer inexpensive. Also, there may be times when one has very high CYA levels but is unable or unwilling to dilute their water right away yet wants to clear their pool of algae.

So what can one do to fight algae other than using chlorine? We've all gone over the various alternatives before, but this time let's see if there is a lesser evil in terms of side effects. Some of this discussion would also be applicable to those who'd rather use Trichlor as a primary source of chlorine (presumably for convenience) and not worry much about the CYA level.

Copper -- this is one of the only algicides (other than chlorine itself) that will kill existing algae in addition to being able to prevent its growth. The downside, of course, is staining and greenish tinted hair if the copper levels or the pH (or sometimes TA) get too high. Copper is also persistent so this isn't a great candidate for a get-in-then-get-out approach. It would be great if one knew the copper levels needed for algae prevention or killing and the levels of pH and TA that can cause the copper to precipitate. The Taylor K-1730 will test for copper, but without knowing the "problem" levels, this is a risky approach.

Bromine -- this is usually created by adding sodium bromide into the pool that already has chlorine in it. Since the bromine doesn't bind to CYA, it is full-strength even at high CYA levels and can kill and oxidize algae. The downside is that one ends up with a bromine pool with a higher chlorine demand as bromine breaks down in sunlight than chlorine in a pool with CYA (bromine breaks down from sunlight more slowly than chlorine if there is no CYA present). Eventually, over weeks (or longer), the bromine dissipates if the levels aren't too high (does it outgas? does it combine with organics and get caught in the filter and then backwashed?)

Monochloramine -- this is usually created by adding an ammonium compound (or one could use ammonia itself) into the pool that already has chlorine in it. Monochloramine doesn't bind to CYA so is at full-strength even at high CYA levels. Though not as strong an oxidizer as chlorine, monochloramine looks similar to ammonia that most algae desire as a source of nitrogen. Once taken in, the monochloramine apparently disrupts algae growth.

Phosphate removers -- this is usually lanthanum chloride which ultimately precipitates the phosphate out as lanthanum phosphate. The main side effect is cloudy water from lanthanum carbonate that is eventually filtered out and replaced with lanthanum phosphate. The phosphate level must be brought down to very low levels below around 125 ppb in order to prevent most algae growth. This product is not very effective in killing existing algae since it is not an oxidizer and any oxidation of algae by chlorine will tend to break up the algae releasing phosphates back into the water. So a phosphate remover is best used as an algae preventative though could slow down an existing bloom if sufficient doses were used to account for the additional phosphates released from oxidized algae. The Taylor K-1106 will test for phosphate level.

PolyQuat 60 -- this prevents algae growth through rather slow mechanisms so isn't very good at killing existing algae. It must also be added weekly since it breaks down from chlorine and is also a clarifier so can get filtered out. It is not absolute and probably can only protect a pool from green algae growth up to around 200-250 ppm CYA (at around 3 ppm FC). I don't know how it does against yellow/mustard algae.

Borates -- this inhibits algae growth so is not suitable to add to try and kill existing algae. It is persistent and a pH buffer and the only apparent side effect is an increased toxicity of the water, mostly for animals (e.g. dogs) drinking cups of water every day from the pool. It may be rather weak so would take the edge off of algae growth but would not completely prevent it under extreme conditions. I also don't know how it does against yellow/mustard algae in terms of inhibition.

Other methods -- am I leaving anything out?

The questions are 1) what is the best approach to killing yellow/mustard algae if one generally wants/needs a higher CYA level? and 2) what is the best approach to preventing yellow/mustard algae from returning if one does not want to maintain the higher FC that is 15% of the CYA level that is known to prevent such growth (say, when such algae is regularly re-introduced)?

For an existing yellow/mustard algae outbreak, looking at the above list it seems that intentionally creating monochloramine through addition of an ammonium product (or ammonia) carefully dosed would create a temporary, though possibly smelly (depending on dose), situation to kill algae in spite of a high CYA level. After the algae has been killed, the monochloramine can rather easily be removed through oxidation by additional chlorine. This meets the criteria of "get-in-get-out" and would allow one to keep the higher CYA level without dilution of the water. The main problem is that I don't know the proper level of monochloramine needed to kill algae nor how long it would take. Some level of shocking with chlorine would also be needed to more fully oxidize the algae itself if it were not filtered out or vacuumed up (perhaps with the aid of a flocculant if one is impatient or where circulation is poor).

For prevention of algae, especially in pools where it is difficult to completely kill yellow/mustard algae or where such algae is frequently reintroduced into the water, then one wants a persistent algicide. In this situation, it looks like borates might be the best bet except I don't know how effective it is against yellow/mustard algae and the level of chlorine one can then use to prevent its growth. PolyQuat 60 used weekly might work but as noted it must be added weekly without fail. Phosphate removers would very likely work and after the initial large expensive dose to remove higher phosphate levels, it's mostly a maintenance dose to get rid of phosphates introduced from fill water or blown-in fertilized soil. If we could figure out the right levels of copper and proper control of pH (perhaps even using borates to help prevent pH rise) then that could work but as noted would be risky (and expensive to fix) if copper levels or pH got too high.

When it comes to those pool owners who prefer the convenience of Trichlor over manual regular dosing of chlorinating liquid or bleach, it used to be that an algicide added weekly such as PolyQuat 60 would be part of "no algae, guaranteed" programs. These days, it seems that phosphate removers are promoted instead. Some Trichlor pucks have copper in them with such copper being the algicide. At least with Trichlor, it is likely for the pH to be on the low side which would reduce the risk of staining, but without copper testing and not knowing limits, this is risky.

Richard

 

[spishex]

There are a lot of trichlor pucks being manufactured with borates built in as well.

Here's my feeling on the products that I've used:

Copper- I've always been disappointed in copper. It's very slow when dealing with an existing outbreak, which leads people to add more and more. Then you end up with precipitated copper in the water so you're fighting green, cloudy water on two fronts instead of one. Maybe it's good as a preventative, but I've seen plenty of pools with measurable copper levels and algae. Not a fan.

Bromine- For as long as I've been in the industry I've had Proteam Mustard and Black Magic (sodium bromide) available to me. I think this is the best on the list for killing existing algae once or twice a season. Unfortunately stores will sell it to the same person over and over again instead of working on good maintenance.

Monochloramine- Since I've always had sodium bromide I've never used Yellow Rid or any of the other monochloramine products.

Phosphate Remover- Since we can only test for and remove orthophosphate from the water, and there are at least five other more complex forms of phosphate that could be present and consumed by algae, I see no use in adding phosphate remover. Especially not in the case of an existing outbreak.

Polyquat- Slow and expensive, but has essentially no chemical downside.

Borates- Again, existing outbreaks are a good excuse to sell borates, but I've never seen them jump into a fight and change the game. I'm agnostic on borates because I was constantly pressured to sell them without ever seeing any benefit for the cost of buying from a pool store.

What I often find with persistent mustard algae, though, is completely non-chemical. In fact, I'm not even a fan of the term "Mustard Algae". Like phospates, we seem to want to lump algae into two or three boxes. Green (easy to kill), Mustard (hard to kill), and Black (easy to distinguish).

I've seen dozens of cases of "Mustard Algae" that were really just algae that wasn't being touched because of bad circulation or and no brushing. Think of a 30k gallon pool with no main drain and all returns pointed up at the surface ("we like to see the ripples..."). The owner goes to the pool store time after time after time. Copper doesn't work. Bromine doesn't work. Borates don't work. Try it all again. By the time the real issue is addressed the pool is a chemical disaster and the guy's wallet is drained.

So with all these products we assume that there's enough motion across the surface of the vessel to attack all the algae in the pool, but if that were the case it probably wouldn't have shown up to begin with.

I think I'm getting derailed a bit here on persistent cases...

So on the occasional (twice a season) outbreak I'm for sodium bromide or monochloramine. Polyquat 60 if the outbreak is just beginning. Borates for maintenance, and never copper or phosphate remover.

 

[duraleigh]

Good morning, Richard,

I plan to reread your post again but wanted to make this observation. How does the average pool owner identify mustard algae? I am willing to believe it is much more infrequent than posters would have everyone believe.

The primary reason is most of us have a need to have our pool problem far tougher than normal.....it allows us all the excuse for the neglect we are guilty of.

Just getting regular algae and not keeping up with pool maintenance is pretty slack but if you can diagnose mustard algae then it suddenly becomes far more palatable to post that up.......it relieves us of some of the responsibility.

I know this is quite a bit off topic but I think it is worth considering. Many posters will be more than willing to pursue mustard algae techniques when everyday adequate doses of chlorine is the cure.

Apologies for the semi-hijack. I'm off to reread and think about what you posted.

 

[JasonLion]

Aside from encouraging the use of borates, I am not sure there is much to be gained here. It seems obvious to me that CYA levels above 80 should be lowered to 80 before fighting algae. It is less obvious, but it seems to me that chlorine is still the most effective approach, even with CYA at 80.

The effective level of copper is the same as the level at which there are likely to be problems. Problems can be avoided through very careful PH management, but this must continue nearly indefinitely and nearly everyone has problems at some point. Nature2 seems to avoid problems by using low, ineffective, copper levels.

Bromine and monochloramine are both very effective when used correctly, but incorrect usage is common and leads to additional problems. If the chlorine demand is not met in a reasonable amount of time, algae is likely to reoccur. The costs are also comparatively high. Reports of success are common, as are reports of problems. Problems can almost always be traced back to not following the directions correctly. It isn't clear to me that either one is less expensive than using chlorine at CYA levels around 70 to 80. The cost picture shifts in their favor at higher CYA levels, but at that point replacing water to lower CYA first seems to be the obvious choice.

Phosphate removers are not recommended for use while you have algae. They can be effective when used as a preventative, though they don't work for everyone. Major problems correlate with the background phosphate level. People with high phosphate fill water experience frequent, significant, problems (mostly cloudy water) and very high costs. Removing a couple of thousand ppm of phosphates is a major pain and a very significant expense. People with naturally low phosphate water often have reasonable success and more manageable costs.

Polyquat can get expensive when used as a preventative.

Borates have some effect when added during an algae bloom. Chlorine is still required at shock level, but borates make the chlorine "more effective". The single seasonal application makes borates reasonably cost effective as a preventative. In my book, borates win hands down as a preventative and have some effect, though hardly an instant kill, when used during an algae bloom. Borates don't "solve the problem", but they do make everything else easier.

 

[reebok]

I have probably had algae 15-20 times throughout the first two years with my pool, and once this year. in the first two years I was absolutely slack about doing anything. I would put tabs in the chlorinator and "shock" occasionally with a 2.5 gallon jug of 10.5%. sometimes I would test with my OTO test. often I found it at 0 and that's when I would "shock". more often than not, I would get green algae on the walls, but not often would I get a full blown green pool (although that is what I had this year). I would randomly use walmart aqua chem algaecide on no kind of regular basis. when I got my full blown green pool this year, I was staying on top of the pool by following the book here http://www.lesliespool.com/browse/Home/ ... 00/I/20575 which states that all you need for an algae free pool is good circulation, filtration, brushing and chlorine. however it doesn't expound on that statement. so I tested about every day or other day to maintain a level of 4ppm with my OTO test. when the pool started getting green I attributed it to the pollen which was bad at the time. but sure enough it was a big algae bloom. I bought stop yellow again and it cleared it up again. I figured the problem must have been poor circulation since I had good filtration, I brushed often and kept my chlorine levels up. so I was looking to get a product called the circulator to increase the circulation in the pool. somewhere around this time I finally found this site. hallelujah.

for every single case of algae I had, I was sold a sodium bromide (pinch a penny stop yellow) product and it worked every single time. basically I would dump 2.5 gallons chlorine, sodium bromide, 2.5 gallons chlorine. and usually I would still have 0 chlorine after that, but the algae would be gone. I never used any other product to kill the algae. I kind of mentioned this here but didn't get a positive response as Jason explained in the last post. algae-clearing-recommendations-t13639.html

one of my first algae outbreaks was a yellowish dust that I thought was dirt. I would brush and it would be back the next day. I mentioned it to my dad and he said "that's algae". I went to the pool store, got stop yellow and it cleared it up. I believe it was yellow algae despite the fact that I think others here don't believe that. I could easily be wrong, but fwiw.

now, as far as borates, I've been meaning to start a post about this, but I haven't yet. consider these numbers I posted in another thread:
before borates, from 5-8-09 to 5-23-09, I used 800oz of 10.5% chlorine. I added borates on 5-24-09 using 20 mule team borax and waterbear's instructions. from 5-25-09 to 7-28-09 I used 1472oz. I keep my FC at 8ppm with a cya of 70.
this is a huge reduction in chlorine use. I never thought about it until I figured it out in response to this thread: phosphates-are-the-food-stuff-of-algae-t16206-20.html
as I started thinking about it, I remember what I posted in the borate thread:
since I added borates, I've noticed some "gunk" all in the bottom middle (lengthwise) of the pool. I call it gunk because that's what it looks like, but it brushes away easily and disappears. it's reappeared a couple times now. my pressure also went up about 5 psi. just wondering if anyone else has had this happen. never seen it in the pool before and cleaned it just before borate (mule team) addition.
waterbear's response was: Very possibly dead algae.
I really didn't think it was, or at least, with all the algae outbreaks I've had, I thought it was weird I had never seen this gunk before. I attributed it to cardboard dust that fell out of the 20 mule team borax boxes. but as you can see from the sharp reduction in chlorine consumption, I bet waterbear is exactly right. so I had a nascent algae bloom that imo the borates killed (or maybe it was all that acid, sheesh that stuff is horrible).

 

[chem geek]

Aside from encouraging the use of borates, I am not sure there is much to be gained here. It seems obvious to me that CYA levels above 80 should be lowered to 80 before fighting algae. It is less obvious, but it seems to me that chlorine is still the most effective approach, even with CYA at 80.

At 80 ppm CYA, the yellow/mustard shock level is nearly 50 ppm FC and normal shock levels often do not kill the more resistant yellow/mustard algae very quickly or effectively so that it doesn't come back right away. That's pretty darn high. If one can use something else for a one-time hit, then that would work around the high shock level or the lowering of CYA by dilution of water and then raising it again assuming it should be high.

Sounds like so far experience has bromine be the best one-time hit though monochloramine might work but people haven't tried the latter as much. For maintenance "insurance", it sounds like borates, though we don't have enough pool users with frequent yellow/mustard algae outbreaks to know if that would help prevent such outbreaks assuming normal chlorine levels are maintained. The Borates do seem to take the edge off of normal algae growth -- we've seen lots of reports of lower chlorine demand and pools that can go low in chlorine without getting fast algae blooms -- but still don't know how well this does with yellow/mustard algae.

As for identification of yellow/mustard algae, we've had discussions of that in other threads. Generally speaking, it usually looks like a yellow or brownish dust, tends to grow on the shady side of the pool, brushes off easily and then resettles, and is more resistant to chlorine requiring an FC around 15% of the CYA level to keep it from growing (at least from the few reports we've had with such experience). I don't think the problem is just poor circulation -- yellow/mustard algae in lab tests takes about twice as much chlorine to kill/inhibit as green algae (see this link, but ignore the conclusions about CYA not affecting chlorine for killing algae -- there may have been ammonium compound contamination in the algae growth medium or some other problems).

Others with experience, please chime in.

 

[Brad S]

At 80 ppm CYA, the yellow/mustard shock level is nearly 50 ppm FC and normal shock levels often do not kill the more resistant yellow/mustard algae very quickly or effectively so that it doesn't come back right away. .

No experience with algea, yet, thank goodness. But, this is one reason why i disagree with the recommended 80 ppm CYA for SWG.

 

[mas985]

I have never had mustard algae let alone any algae bloom so I'm not sure that I can relate that much. However, I wonder about how long it takes to kill this type of algae or for that matter any other type. Does the kill time depend on the level of chlorine? If so, would it not be better to go with a much higher level of CL in the first dose to have a much shorter kill time. In fact, is there a chlorine level which would have a kill time measured in minutes or low hours?

One of the reoccurring themes on algae problems seems to be not using enough chlorine for long enough to ensure a full kill. It might be easier to go with an extra high single dose of CL to ensure a quick kill. Similar to pulse therapy in medication. Over the long run, this could end up costing less since only one dose may be required. Of course this might not be too practical for vinyl pools but a bit higher might help.

The phosphate level must be brought down to very low levels below around 125 ppb in order to prevent most algae growth.

Interesting comment. Some studies have suggested levels below about 1000 ppb don’t seem to influence algae growth much. I would assume that other algae food such as nitrates would need to be removed as well?

 

[JasonLion]

Sodium bromide based products suggest using 4-5 oz per 10,000 gallons along with around 6-8 ppm of chlorine. Various reports suggest that additional chlorine will be required. Sodium bromide costs around $10/pound, so the total cost can be reasonable, contrary to what I remembered.

Products that work via monochloramine suggest using 20 oz per 10,000 gallons along with around 24-30 ppm of chlorine. They also require that the PH be 8.0+, which will result in additional chemical requirements and could lead to scaling in some situations. These products cost around $7/pound.

 

[Guest]

I plan to reread your post again but wanted to make this observation. How does the average pool owner identify mustard algae? I am willing to believe it is much more infrequent than posters would have everyone believe.

The primary reason is most of us have a need to have our pool problem far tougher than normal.....it allows us all the excuse for the neglect we are guilty of.

Just getting regular algae and not keeping up with pool maintenance is pretty slack but if you can diagnose mustard algae then it suddenly becomes far more palatable to post that up.......it relieves us of some of the responsibility.

I know this is quite a bit off topic but I think it is worth considering. Many posters will be more than willing to pursue mustard algae techniques when everyday adequate doses of chlorine is the cure.

Apologies for the semi-hijack. I'm off to reread and think about what you posted.

Wow!

My pool has been between 20 & 30 FC since July 23rd, with daily brushing (sometimes 2 to 3 brushings per day). Algae still appears. Prior to that, it has never been "neglected."

I'm pretty sure that the algae problems are because the wedding-cake type steps get poor circulation under them. I move them around and brush under them. Despite the high chlorine, pretty much every time I move the steps, there will be some algae under them, even if I move them 3 times daily.

I had some algae spots appear a few times last year, my first year owning the pool. This year it's been quite persistent; also, the weather has been much cooler and rainier, so it's more work and less enjoyment than it was last year. The steps I bought about a year ago. I'm tired of having such high chlorine but it seems to be what I need to do to keep the algae at a minimum.

Aside from a little algae here and there that disappears with brushing (creating a greenish/brownish dust that quickly dissipates), the pool looks great. It's never been a green swamp (well, not since my first opening last year after it sat unused for a couple of years); it just has some small spots that appear on the walls and floor pretty much daily. I'm pretty sure that if I didn't brush, they'd quickly multiply.

I can only hope that someday you'll have the opportunity to try to conquer this yourself so that you won't feel compelled to make statements like those quoted.

 

[chem geek]

The phosphate level must be brought down to very low levels below around 125 ppb in order to prevent most algae growth.

Interesting comment. Some studies have suggested levels below about 1000 ppb don’t seem to influence algae growth much. I would assume that other algae food such as nitrates would need to be removed as well?

waterbear and I disagree on whether algae can grow without phosphates (i.e. can they grow only with nitrates, carbonates, sunlight, water). I know that the other way around is true -- cyanobacteria can make their own nitrates from nitrogen gas (i.e. they are nitrogen-fixing bacteria), but I thought that all algae needed phosphorous (for ATP, DNA and other chemicals).

However, I hadn't considered what spishex wrote about there being other forms of phosphates that algae can utilize. The phosphate removers will only remove orthophosphate. Perhaps that explains why the phosphate removers don't seem to work in some situations.

 

[chem geek]

I have never had mustard algae let alone any algae bloom so I'm not sure that I can relate that much. However, I wonder about how long it takes to kill this type of algae or for that matter any other type. Does the kill time depend on the level of chlorine? If so, would it not be better to go with a much higher level of CL in the first dose to have a much shorter kill time. In fact, is there a chlorine level which would have a kill time measured in minutes or low hours?

One of the reoccurring themes on algae problems seems to be not using enough chlorine for long enough to ensure a full kill. It might be easier to go with an extra high single dose of CL to ensure a quick kill. Similar to pulse therapy in medication. Over the long run, this could end up costing less since only one dose may be required. Of course this might not be too practical for vinyl pools but a bit higher might help.

The rate of kill should roughly be proportional to the active chlorine concentration. So this is why we recommend the higher shock level for a reasonably fast kill time even though technically people could probably shock with perhaps half that level and still kill the algae faster than it grows, but take longer to clear the pool. There is also the issue of having enough chlorine to not run out as it gets used up quickly initially if there is a lot of algae.

Now the issue of a "full kill" is trickier. This has more to do with getting at algae in areas with poor circulation. With yellow/mustard algae that likes to grow in shady areas, this is a particular problem because such areas include behind light niches, under stairs, inside regularly used poles, etc. With green algae, if you don't kill it all during shocking, then even normal chlorine levels will eventually kill it off. With yellow/mustard algae, a higher active chlorine level is needed in the well-circulated areas of the pool and even that isn't enough in the poor circulation areas so such algae often comes back after a shock.

 

[Guest]

However, I hadn't considered what spishex wrote about there being other forms of phosphates that algae can utilize. The phosphate removers will only remove orthophosphate. Perhaps that explains why the phosphate removers don't seem to work in some situations.

BINGO! It also backs up my point that nitrates and not phosphates are the limiting factor in algae growth!

 

[chem geek]

Products that work via monochloramine suggest using 20 oz per 10,000 gallons along with around 24-30 ppm of chlorine. They also require that the PH be 8.0+, which will result in additional chemical requirements and could lead to scaling in some situations. These products cost around $7/pound.

Well, that's just plain odd. I'm not sure why they use so much chlorine unless they generate a LOT of monochloramine in roughly the same amount. Also, I'm not sure about why the much higher pH is needed unless they are trying to avoid the formation of nitrogen trichloride (or could be related to the specific ammonium salt used). At least with this technique, one could buy ammonia for probably a lower cost.

HTH Yellow Rid appears to be ammonium sulfamate which decomposes into ammonia and sulfur trioxide (the ammonia reacts with chlorine to form monochloramine). I don't know the concentration of product, but would figure that the recommended chlorine level mostly combines with the product to form monochloramine -- it's just awfully high and therefore surprising to me.

If the sodium bromide didn't have the side effect of continued higher chlorine usage for a while (due to being a bromine pool), it would be a more reasonable approach. I suppose it's not that bad, but I'd prefer something you could get rid of and be back to "normal" as soon as possible. Chlorine is obviously best, but for the high CYA case I'd prefer something with smaller dosing and that was eliminated after being used. Oh well, I had higher hopes for monochloramine but I don't like the apparently high doses required.

 

[Guest]

Richard,
Edited for politeness by Moderator

I guess saying 'drinking the koolaid' is against forum rules according to FPM!

Copper is not an option, the drawbacks far outweigh the benefits. The ONLY time I would consider it is in a SEVERE case of black spot algae when all else has failed.
Bottom line is this, halogens (including monochloramine and bromine) kill algae and everything else (except copper) just inhibit it. Also,. as spishex pointed out, copper is not always THAT effective unless the dosage is very high (above the recommended .6 ppm for killing algae). If the copper is high enough to inhibit or kill algae it's high enough to stain and turn hair green. Staining can be minimized by keeping on top of water chemistry but if someone was doing that in the first place they would not need to add copper to their pool to keep the algae away or kill it, would they? Copper is a crutch for the lazy until they get their first staining problems or green hair and learn it was from the copper.

The biggest problem with sodium bromide, as spishex pointed out, is that it tends to be overused and becomes another crutch. If it needs to be used more than once then the pool has too high a CYA and the level needs to come down. Period!
Bromine is probably a bit easier to use than ammonia but both create a chlorine demand and tend to get overused instead of fixing the problem. Often trichlor is the problem. If there is a cartridge filter then trichlor should be avoided at all costs. We know what works and what doesn't.
Fix the problem, don't put a band aid on it!'
As you know both sodium bromide and inorganic ammonia are most effective when the pool has very high CYA levels. They are only a temporary band aid and until the underlying conditions of too high a CYA are fixed the algae WILL return. To suggest their use is not going to benefit the pool owner. Getting their water in line and educating them will.

Looking for the 'magic in a bottle' which is what you seem to be trying to find now, often costs more money in the long rung than actually getting the water in line.
If the algae is because the CYA is too low or the FC has been sporadic or too low then get some chlorine in the pool and keep it there (by upping the CYA if needed).
If the problem is poor circulation then get off your butt and brush the pool more often. Brushing down the sides of a pool create currents that 'stir' up the water and help with dead spots.
Sorry if these answers seem blunt but they are the solutions.

To kill an existing algae bloom polyquat can be effective in conjunction with chlorine.
First shock the pool in the evening. The next morning add the polyquat 60, that evening shock agian.
Unless the algae bloom is very bad this works (and it even works on mustard).

If the pool is a green swamp then sodium percarbonate will clear it, often in about 48 hours. You neglected that in your first post, perhaps you are not familiar with its use.
10 lbs per 10k gallons along with 7.5 lbs sodium bisulfate to maintain pH.
(It works out to 1 lb sodium percarbonate and .75 lbs sodium bisulfate per 1000 gallons.)
Water level should be higher than normal since otherwise you will see the clean ring around the pool at the waterline.
It will cause leaves and debris to float so it can be skimmed out.
If the pool is not totally clear in 48 hours of filtration it can be repeated or you can start shocking with chlorine.
This is probably the fastest way to clear a green swamp and is the closest I have ever seen to 'magic in a bottle'.

Plain old unstabilized chlorine will work also. If the pool is not vinyl then nuke it! This comes pretty close to 'magic in a bottle' too!
This also works when there is chlorine demand from ammonia or nitrates.
IF the pool is vinyl then use the shock and polyquat approach or sodium percarbonate for algae, or (for ammonia and nitrate) dilutions (drain and refill) are going to be the fastest way to deal with the problem.
Education on proper pool care is the ONLY thing that will prevent the problem from reoccurring.
Commercial pools do not have these problems and cannot afford to be closed for a week for shocking. Preventive algae control is what is used in a well run commercial pool and is what we teach here.
Sadly, there is no 'magic in a bottle'.

The use of borates and polyquat 60 (or linear quats for that matter, with all their drawbacks!) can provide insurance in marginal pools or when pool care is sporadic but if there is an algae outbreak there is not easy way to cure it. Proper care in the first place is actually easier.

 

[Guest]

Products that work via monochloramine suggest using 20 oz per 10,000 gallons along with around 24-30 ppm of chlorine. They also require that the PH be 8.0+, which will result in additional chemical requirements and could lead to scaling in some situations. These products cost around $7/pound.

Well, that's just plain odd. I'm not sure why they use so much chlorine unless they generate a LOT of monochloramine in roughly the same amount. Also, I'm not sure about why the much higher pH is needed unless they are trying to avoid the formation of nitrogen trichloride (or could be related to the specific ammonium salt used). At least with this technique, one could buy ammonia for probably a lower cost.

HTH Yellow Rid appears to be ammonium sulfamate which decomposes into ammonia and sulfur trioxide (the ammonia reacts with chlorine to form monochloramine). I don't know the concentration of product, but would figure that the recommended chlorine level mostly combines with the product to form monochloramine -- it's just awfully high and therefore surprising to me.

If the sodium bromide didn't have the side effect of continued higher chlorine usage for a while (due to being a bromine pool), it would be a more reasonable approach. I suppose it's not that bad, but I'd prefer something you could get rid of and be back to "normal" as soon as possible. Chlorine is obviously best, but for the high CYA case I'd prefer something with smaller dosing and that was eliminated after being used. Oh well, I had higher hopes for monochloramine but I don't like the apparently high doses required.

The easiest way to do the monochloraime treatment (although not the safest) is with anhydrous ammonia. One gallon per 10k gallons opened UNDER WATER! It raises the pH to ensure the formation of monocloramine. That is why the ammonium salts say to raise the pH first, to maximize the monochloramine formation. After the algae is dead you still have a pool with a lot of ammonia in it. You know firsthand what that is like, Richard! Why even suggest it?

Bromine products also require raising the pH. United Chemical products are an example. I suspect it is for the same reason, to form bromamines that the algae will consume. Then again, Jock Hamilton did a lot of strange things with his bromine pool products and his 'Hamilton Index' that were never fully explainable.

 

[chem geek]

Prevention is obviously the best approach and that is most easily done with chlorine and possibly having borates as a backup. The only reason I'm looking at these other algaecide alternatives is when we have these cases of high CYA where the pools want to keep their high CYA (say, 80 ppm for SWG or very intense sun areas) and they have yellow/mustard algae. Fortunately, yellow/mustard algae is far less common and much of the time it turns out to be pollen and not algae, but in those cases when it occurs it can be a bear to get rid of.

I totally agree with you that if the pool owner continues with bad practices such as continued use of Trichlor having the CYA continue to climb, then the problems will come back. I'm not talking about those situations, but rather those where one is properly managing their CYA levels but for whatever reason got yellow/mustard algae in their pool which can occur even when doing everything "right" since that algae is more resistant to chlorine. I'm not looking for any magic in the bottle -- chlorine definitely works. It's just that we have some situations where we say have a higher CYA level (60-80 ppm) and IF one gets yellow/mustard algae at that high CYA level then it would take a lot of chlorine and there might be another alternative.

I wasn't talking about heavy algae outbreaks where sodium percarbonate could be used in place of lots of chlorine, though that is certainly good to know.

As for the ammonia/monochloramine, if the amounts required weren't that high then it wouldn't take a lot of chlorine to get rid of. I had thought that the dosing might be something less than 5 ppm (monochloramine, not ammonia) which is quite easy to form and to get rid of but I was apparently mistaken.

 

[Aquaclear-NZ]

We often see case's of mustard algae over the summer here, and have a method that has always fixed

As mentioned straight copper based alagecides and phosphate removers as killers are a waste of time for a quick clear, and based on the high levels of chlorine required to kill this persistent Crud, selling someone 100L of liquid chlorine or bleach isnt really part of the game plan (i can just see the look on their face now.

I have found 2 alagecides to be particularly effective, and while i wont spout brand names, there are plenty of pool service technicians in both NZ and Australia that will sing its praise.
Alagecide 1)
Formulation details: Organo copper complex 19.0gm/litre
Alkyl Dimethyl Benzyl Ammonium Chloride 100gm/litre

Average sized pool (13,000gal/50,000L) requires 2.5L hit, or 50gm chelated copper

Algaecide 2)
Formulation details: 285 G/L 1, 2-Ethanediamine Polymer with
(Chloromethyl)-Oxirane and N-Methylmethanamine
Long life (monthly) polyquat algaecide.

combined with some of the techniques above (lower cya & shock dose 24 hours before adding and again after)

correct sanitiser maintenance, reduced phosphate level and regular algaecide are really the only effective method to keep this at bay, although i do believe thta after a period of correct and proper maintenance the later 2 can be removed from the occaision.

I quite often get calls from around NZ from people that have spent a fortune in their local pool store on Crud and misinformation that has not really worked for them, and as a wholesaler i am often the last point of contact for under educated experts who are also at their wits end.

This method has served me and my clients well over the years, and while i will make no excuse that it is the cheapest way to do it, (in the long run its not far off though) it does work, and i also guarantee it with a money back option if it doesnt work. Since finding this site, and a bit of back and forth corespondence with Chemgeek, expanding my understanding of cya vs chlorine has helped make this method even more effective

 

[Brad S]

It also backs up my point that nitrates and not phosphates are the limiting factor in algae growth!

Proves nothing of the sort. Only means that orthophosphates cant contribute to algea growth if they are removed. If other forms remain, algea still has a supply. Doesnt say one thing about whats the limiting source. Living things, (you, me, algea, etc,) can not live with out a renewable supply of phosphates. No ATP, no life.

 

[JasonLion]

Just to clarify, monochloramine product directions split the chlorine into three doses, one when the ammonia product is added and two more after 12 and 24 hours. I my previous post just stated the total amount.