How can I have algae w/these test results?

[OneMom]

Hi:

We opened our pool with a pretty low CYA level this year and by the end of June our CYA had dropped to 20. Since we were leaving for a week, we turned on our auto-chlorinator. We've continued to use it since July and just turned it off last week because it's nearing a level of 50. (That's not a problem for us right now because we'll be closing our pool in two weeks.) Once we started using the chlorinator, we raised our TA to 100, like the "Recommended Levels" chart says, since our pool is vinyl.

We battle yellow mustard algae, so we always keep our FC on the higher end. We had to shock it two weeks ago because of heavy pool use & the FC level has dropped very slowly because the water is cold & we've had the solar cover on most of the time. We uncover the pool 1/2 way every fourth day to run the Polaris for approx. 3 hours. We did have the cover completely off of the pool all day on Sunday.

Today, the water is light green & we clearly have green algae growing on the bottom. I don't think it's mustard algae, because when we have mustard algae it always grows up the slanted side on the deep end (along with everywhere else). In addition, the mustard algae never looks bright green like what I'm seeing today.

All of my readings look decent, except PH needs to be raised. I re-tested THREE times, because I don't see how I can have algae with these test results:

CYA: 47
FC: 12
CC: 0
TA: 100
PH: 7.2

Could low PH have been the cause of the algae? If not, I'd assume that I don't actually have algae, but the water is visibly light green and the algae is pretty thick in spots on the bottom. In addition, when I use my fingers to scrub the algae that is visible on our white steps (and on the white steps on our ladder) I really have to rub to remove it. It doesn't just drift away easily into the water like dirt and pollen do. What am I missing?

 

[Bama Rambler]

How are you running the pump?

If you're not running the pump enough you could be getting localized spots of low FC.

I also think you're leaving the cover on too much.

 

[OneMom]

The pump runs 12-15 hours a day EVERY day.

So it's possible to get algae, with those test results, if the cover isn't removed enough? How often should the cover be removed? Does it have to come off all of the way? Or is 1/2 way enough?

 

[Bama Rambler]

If you weren't having a problem my recommendation might be different, but since you are, I'd recommend removing it completely at least every couple of days on sooner. You also might want to bleach the underside of your cover while you have it off. Several posters here have found algae clinging to the underside of the cover and hiding in any bubbles that have burst.

 

[chem geek]

This is truly strange, assuming this is green algae. I assume you have your own good test kit so the FC and CYA numbers are accurate. With the auto-chlorinator, at a 1 ppm FC per day usage that you might have with your covered pool (does that sound about right?), every month of Trichlor use would add about 18 ppm CYA. So after 2-1/2 months it would go from 20 ppm to 65 ppm if there were no water dilution and if my daily chlorine usage assumption was correct. Anyway, it sounds like it's in the ballpark.

Light green, especially if clear and not cloudy, also sounds like copper, but it doesn't sound like anything was done such as using a copper-based algicide or having a metal ion system get out of whack or anything like that. It is also a bit strange that you have to scrub the substance rather hard to remove it -- though yellow/mustard algae is like dust, even green algae doesn't stick that much unless it's quite old (black algae sticks a lot, but is far less common in vinyl pools). Do the white steps feel slimy or is it more sticky? Green algae would tend to feel slimy.

Though you could try shocking the pool to at least 20 ppm FC and perhaps 30 ppm FC, I wonder if some sort of other substance got into the pool such as deteriorating cover material or something from the filter -- you should probably check your filter just in case.

Another thing you can do is to collect some of the "algae" and put it into a bucket of pool water and have it out in partial sun (half cover the bucket) and see if it grows. If it does, then it's algae or something that grows (obviously); if it doesn't, then this could be something chemical instead.

Richard

 

[OneMom]

Hi Chem Geek:

We get our test kits from TF Test Kits. (Isn't that Duraleigh's business?) You were correct with your assumption that we lose an average of 1 ppm of FC per day when the pool is covered. (Sometimes less, depending on conditions.)

I just got done brushing & found that even though the slopes in the deep end didn't have a "visible" growth of algae, large yellowish/green clouds kicked up as I brushed there. As I brushed the rest of the pool, I saw the same results in most of the areas. The only areas that I had to scrub over a couple of times were the places that had the thicker green spots. (So, as far as my earlier statement about having "to rub to remove it", the problem must have just been that I was only using my finger...and I was rubbing at one of the thicker green spots.) Anyway, this is what we've seen in the past when we've had the mustard algae. I've just added my last bottle of chlorine, which only brings the FC up approx 5ppm, and have to go buy more AGAIN. Now that I'm done scrubbing, the water is very cloudy, but all of the green spots are gone. Well, they're gone for now. When we get this type of algae we spend HOURS brushing the pool until our FC holds overnight.

I have to say that we are BEYOND frustrated. We just can NOT win the battle with this stuff this summer. I don't think that I'm exaggerating when I tell you that we have had our pool at (or above) shock level on and off for half of the summer. When we are fighting the mustard algae we run the pump 24/7 until the overnight FC test is stable. After that, we CONTINUE to run it 24/7 for almost a week because it takes a long time to filter out the dead algae completely. The amount of money we've spent on chlorine & electricity is ridiculous. On top of that, the weather here this summer has been unusually cool. The few warm days we have had, we've rarely been able to use the pool because of how high the FC was. My husband & I were able to swim three times this year. The kids only were able to go in five times. This is the first time in twelve years that we regret having a pool. It just hasn't been worth it.....especially because I don't have faith that this won't happen again. I keep feeling like we have some mutant strain of mustard algae that just can't be beat. (Kind of like some infections that have become antibiotic resistant. LOL) I don't know any other pool owners that use test kits or this forum. I've always felt a little arrogant about how much more knowledge we have using the BBB method. However, this stuff has kicked our *** and I feel like a complete idiot at this point of this summer.

Sorry for the long rambling vent. I'm just so tired of this stuff. I know it's expensive, but do you think we'll have better luck avoiding this next year if we add borates? If not, what should we do? You're a smart guy. Please say "abracadabra" and fix this for me! :lol:

 

[crek31]

Any chance your reagents are old or were stored incorrectly? I have no idea if that would give falsely high FC (or low CC) readings, just looking for variables to double check. For what it is worth, ABRACADABRA and ALACAZAM! Good luck.

 

[chem geek]

First off, I'm sorry you are going through this and it's clearly very frustrating.

Well, you've got a variety of choices of algicides or equivalents that could be used, but using 50 ppm Borates is a one-time dose with multiple benefits and only one known side effect. If you have dogs that drink cups of water from the pool every day, then you'll need to teach them to drink from a bowl instead. Other than that, the borates will not only help inhibit algae growth (at least taking the edge off of the growth), but will also act as a pH buffer.

All other choices start to get expensive in maintenance doses or have side effects. PolyQuat 60 added weekly would also take the edge off the algae growth hopefully letting more normal chlorine levels prevent the algae from growing. For completely getting rid of mustard algae, it looks like the sodium bromide treatments are the best bet other than super-shocking (at the higher yellow/mustard algae shock level). After that, you get to more one-time expense and side effects with things like phosphate removers that may or may not work completely, may cloud the pool, and are expensive if you've got a lot of phosphates. Copper algaecides can stain if you're not careful. That's pretty much the extent of all products, but except for the borates and PolyQuat and possibly sodium bromide for special cases, none of the others are recommended on this forum.

If your vinyl liner is blue, then yellow/mustard algae can look green since yellow plus blue makes a green color. So from your descriptions and the resistance to chlorine, this does sound like yellow/mustard algae that's pretty fierce. Did you ever try shocking at the yellow/mustard algae level of around and FC that is 60% of the CYA level and put in all pool equipment used in the pool (i.e. poles, brushes, nets, etc.) and wash your swimsuits? Are there any light niches or ladders or other places the algae, which prefers shade, can hide?

Richard

 

[OneMom]

Chem Geek/Richard wrote:

First off, I'm sorry you are going through this and it's clearly very frustrating.

You're so nice...I'm really sorry for my little melt-down earlier!

If your vinyl liner is blue, then yellow/mustard algae can look green since yellow plus blue makes a green color. So from your descriptions and the resistance to chlorine, this does sound like yellow/mustard algae that's pretty fierce. Did you ever try shocking at the yellow/mustard algae level of around and FC that is 60% of the CYA level and put in all pool equipment used in the pool (i.e. poles, brushes, nets, etc.) and wash your swimsuits?

Yep, our liner is blue and yes, we super shock to yellow/mustard levels EVERY time we have this. We even use the infamous "Chemgeek's Best Guess Chart" to do it. In fact, when we use your chart, we err on the side of caution, and actually keep the FC 2-3 ppm HIGHER than you recommend. We keep the brushes and nets in the pool during this process, just in case. In addition, because we've had to keep our FC so high, last summer I began to wash our swim suits after each use. (Or else they fall apart pretty quick.)

Are there any light niches or ladders or other places the algae, which prefers shade, can hide?

We do have lights & ladders, but we scrub them like crazy. As this problem has persisted this year, I've worried that I've missed something, so I now get in the pool to scrub every possible surface. I have unscrewed the outlet jets to scrub them as well. My husband has even taken out the lights so I can scrub them, the cords, etc. It makes me nervous to get in water with 60% (and higher) CYA, but I'm desperate at this point. I'm beginning to wonder if the mustard algae is lurking in some of the coping (if that's what it's called) along the pool edge. If that's the case, there's not much I can do about it. Or maybe the fact that our yard backs up to the woods is the problem. I don't know what actually causes mustard algae, so I'm just grasping at straws at this point.

Anyway, thanks for the advice about the Borates. Our dogs aren't allowed to drink out of the pool, so that won't be an issue. We were thinking that we would like to try adding Borates next spring & it's reassuring that you think it would be worthwhile to try that as well. We really appeciate that you've taken the time to answer this post!

 

[duraleigh]

I do not believe borates will solve your issue with algae. Borates is an optional additive that may help in the prevention of algae.......in an adequately chlorinated pool.

Somewhere over the summer, you have allowed your FC to get low enough for algae to exist. That you have had algae several times this summer indicates the pattern of too low FC in the pool repeats itself. Once that starts, then cleaning it out and shocking is a hugh chlorine consuming process.

Of course, it's too late in the season to worry much about it now, but I suggest when you open next Spring, that you post numbers here on the forum and report your water conditions on a bi-weekly basis. I believe strongly we can help from algae ever getting a foothold and simplify your pool maintenance and reduce your costs dramatically.

Again, I do not believe borates will cure the problems with your pool. Adequate chlorine levels and CYA, etc. etc. works in virtually every pool on this forum......we can help make it work in yours, too.

 

[H2O_Keeper]

I experienced a similar problem this year where I just kept fighting algae and literally thought it was the green kind and only went to that shock level. I had the dust blow away stuff but thought since the water appeared more greenish it was not mustard alagae. I once went to the mustard algae level and it came back again. I was frustrated as well trying to figure out how in the world could this be happening. The test kit was not showing the overnight chlorine loss per the usual clue the algae is gone.

I finally just took it to Mustard Algae shock for 72 hours, kept brushing and it went away (disregarding FC loss at night). Its been gone for almost a month now.

It was a tip on this forum that hit home, shocking is a process, not an event..... I thought nothing could live taking it to 32FC and leaving it there overnight. But without the continued brushing and keeping it there for an extended period I couldn't clear it. I think I had pockets or something as well. My pump was running 24/7 over the constant trying to kill it with my 2 month battle.

Hope this helps.

 

[crewchief47]

Just to make sure, you have scrubed the solar cover during treatments (most of us 'assume' you have)? You mentioned the ladder etc. but not the solar cover.

 

[OneMom]

Duraleigh wrote:

Adequate chlorine levels and CYA, etc. etc. works in virtually every pool on this forum......we can help make it work in yours, too.

Hi Duraleigh:

I completely believe in the BBB method & have followed it since I found you guys on the old forum. (I can't remember the name of it now. I found it when you guys were still at that site & the "owner" of the forum had been MIA for a long time.) I followed you here once you started this one. The BBB method was a completely new concept for my husband & I back then, but it made total sense to us.....it's just basic chemistry. We were grateful to find a definite way to maintain our pool. I eventually convinced my husband to pay the money to join here because I wanted to see this site succeed. (Plus, from a selfish point of view, I didn't want to lose this resource. lol) He also saw the value in supporting this site & we've been happy to see it grow.

The reason I posted wasn't because I was doubting BBB & it's effectiveness, it was because I feel positive that I'm missing something or doing something wrong. I know that if I always keep my CYA & FC at the correct levels it will be easy to maintain my pool. In fact, last summer we started a "Pool Notebook" to keep track of all of our test results. Every time we test we note the date & all test results. We even keep track of the amount & type of chemicals we add to the pool. Anyway, when I go through the notebook, day by day, it clearly shows that the FC has not dropped below the minimum. In fact, the majority of the summer it has been well above the minimum.

The exception is the date of July 11th, when we returned from a week's vacation. At that time our FC had dropped almost 1 ppm below the minimum. There weren't any signs of algae, but we still shocked the pool & held it there for three days, even though we didn't see any overnight FC loss after the first day. (Sorry to "meander" off the subject here, but I just have to tell you how much we like your test kits. Plus, your turn-around time between ordering & delivery is amazing.) I apologize for the A.D.D. moment...back to business now. lol

crewchief47 wrote:

Just to make sure, you have scrubed the solar cover during treatments (most of us 'assume' you have)? You mentioned the ladder etc. but not the solar cover.

We don't keep the cover on throughout the entire shock process, we're worried it would fall apart in a couple of weeks. However, we do have it on for about 24 hours while the pool is at shock level. We also hose it down after that. We have NEVER scrubbed it with a brush though. Holey moley!! That's got to be what we've been doing wrong. How on earth do you scrub it? There have been times it's gotten dirty from rain, etc., but we've just hosed it off & wiped it down with a cloth as we unrolled it. Our cover is really large. It more extends the entire length & width of our driveway. Should we be detaching it from the reel, dragging it out front onto the driveway, & scrubbing it on our hands & knees? What mixture of bleach & water should we have in the bucket?