New User Getting Butt Kicked By Algae

[TCP007]

Hello: I live in SW Michigan and have a rectangular, gunite pool. It is 36' x 18' and holds approximately 30,000 gallons. I have lived here and wrestled with this pool for 8 years. This year has been a real head-scratcher for me, but I guess I've just always had good luck. I believe I have mustard algae that keeps coming back within a week or so of eradication (or so I thought). I have been using AquaCheck 6 panel strips, but I am going to order a Taylor test kit via the links provided here. My CYA is low (0 or below) and PH high (8.4 range). TH, TC, FC all appear to be good. TA had been a bit high. I added 2 gallons of HCL last week and it helped. PH appears to be between 7.2 and 7.8, but CYA is still low (somewhere between 0 and 30, but closer to 0). TA came down closer to 180. I am vacuuming all visible algae to waste right now (pool level coming back up now) and will brush walls. I picked-up another 2 gallons of HCL and 10 gallons of liquid chlorine. I have more reading to do on your site, so not quite sure how many gallons of Chlorine I'll dump in. I'll add 1 gal of HCL and wait to test, but I'm guessing I'll end up adding both gals. It appears that my chlorine isn't working effectively with my CYA so low. Sorry for this yawn-inducing post, but... this is why I have joined. It didn't take me long to realize the moderators here know what they're doing. I appreciate reading and learning from all the experienced pool lovers here.

[TCP007]

Update: I ran out of daylight vacuuming to waste, so did not shock. I did add both gallons of HCL, and as of this morning I only noticed a slight improvement in the CYA. I did notice that it appeared to bring down both TC and FC readings. I plan to finish vacuuming visible algae after work. I think I should add another gallon of HCL (?) before adding the the liquid chlorine.

Test kit has been ordered and appears to be on schedule for a 8/7/14 delivery. Sorry I don't have better info at this time.

I failed to mention that the pool utilizes a sand filter (not sure what brand, but it's black with a multi-function selector on top), a 2-hp Hayward Super Pump. I replaced the sand 4 or 5 years ago. Solar blanket provides more than enough warmth. Unfortunately, this pool gets sunshine almost the entire day. I am currently removing the blanket at night to let some heat out. Current temp and humidity isn't helping much.

[Watermom]

Kinda hard to know how to help without some good numbers. Hopefully your kit will arrive tomorrow.

HCL is ??? and why are you adding it?

Welcome to the Pool Forum!

[TCP007]

HCL is Muriatic Acid or Hydrochloric Acid. I'm adding in order to raise my CYA level and also bring my PH and TA down.

I decided not to wait another day for the kit (and hope it actually arrives as estimated), so I added another gallon of Muriatic Acid and later shocked with 10 gallons of liquid chlorine. Hoping for better results with the extra gallons of chlorine.

I will definitely provide better readings when the Taylor test kit arrives. Thank you!

[Watermom]

HCL or muriatic acid will not raise CYA. You need cyanuric (or isocyanuric) acid.

[BigDave]

@Watermom: HCl is hydrochloric acid, it's the same as muriatic acid. I think it's being used to lower TA.

@TCP007: Don't let the pH drop below 7, it can damage your pool. If you are trying to reduce TA, you'll need to aerate the pool to bring pH up after adding HCl.
If this were my pool, I would concentrate on killing and removing the algae before trying to adjust TA, 180 is high but livable. The test stips are useless for CYA but if you see alge, you need more bleach. Hopefully the K-2006 arrives today and you can get a good measure of CYA level.

[Watermom]

For some reason I didn't think muriatic and HCl where the same exact thing which is why I questioned it. But, I did a little research and found out they were. Thanks, Dave. But, he also states that he is using it to raise CYA which I addressed in my post above yours.

[BigDave]

@Watermom: Ah! I didn't see that post before responding, thanks.

@TCP007: I stand behind my advice in post #6 and Watermom is right, HCl won't raise CYA.

[TCP007]

Thanks to both of you for responding. I used liquid chlorine, so if I'm correct... this will not help my CYA. I did add 10 gallons of liquid chlorine, so hoping it will take care of my algae issue. I use granular (99% Sodium Dichloro-S-Triazinetrione) which I dilute in water and pour into pool, along with 1" tabs in my floater (98.6% Trichloro-S-Triazinetrione). These are supposedly good for keeping my CYA up, yes? Soooooo... maybe I've been adding too much water with all the vacuuming to waste I've been doing!?

Thanks again for the help. Hoping to share better news very soon.

[Watermom]

Dichlor and trichlor do both add CYA. Go ahead and order that Taylor K2006 kit as soon as possible so we can find out your CYA reading.

[TCP007]

The kit was scheduled for delivery today, but I checked earlier and now it's looking like tomorrow. I'll be lucky to have good numbers before Sunday as my schedule is booked solid over the next 2 days. But... I'll post numbers asap.

Final question for today: Now that I have "super-chlorinated" with liquid chlorine (last night)... when should I think about adding any Dichlor again, and trying to get that CYA number up? I've noticed my TC and FC levels don't seem to change very fast, and are usually on the higher end. Before I shocked last night, the FC was between 3 and 4, and the TC was closer to 8. So, I doubt those levels will drop within the next couple days or so. My only concern is that I have kids that are anxious to get back in the pool. Thanks, Watermom!

[Watermom]

I just really can't give advice based on test strips. They are just not reliable. Even though you have ordered a K2006 (good decision to do so, btw!), you'll still want a cheap OTO/Phenol Red kit (yellow and red drops) for quick daily checks. See if your Walmart or Lowe's has one and use that. If they don't, a pool store will, but just don't let them talk you into a bunch of other stuff while you are there. They will try!

If your CYA really is as low as your strip indicates, your chlorine level will drop pretty fast.

How does your water look?

[CarlD]

CYA indicators on test strips, even Hache and LaMotte (the two best brands) are virtually worthless. About all they MAY tell you is if you have 0 stabilizer in your water.

[TCP007]

Test came and here are my results:

FC = 22.5
CC = 1
PH = 7.3
TA = 200
CH = 170
CYA = less than 30. Dot was still visible after small comparator was completely filled.

I am reviewing the treatment tables, but wanted to post my results immediately. Thanks for suggestions in the meantime.

Additional note and question:

My chlorine results could be wrong or skewed. I took a few minutes to read some materials/tables AFTER my sample went from pink to clear. I then added more reagent until it went clear again, which added to a higher FC result. The initial calculation would've put my FC at 17.

Perhaps I need to wait a couple more days to test for chlorine, since I just super-chlorinated 2 nights ago. (?)

I think the other results are accurate.

[CarlD]

OK, since you have your K-2006, let's go over how to test for FC. I know this may be redundant but for those of us who have done the FAS-DPD testing for a decade or more it may help to review:
1) Rinse the test tube.
2) Point the tube opening DOWN and push it down about a foot under the water, then invert it so it fills BELOW the surface
3) Pour off water until it is at the 10ml line.
4) Add one scoop of DPD powder. The water should turn pink or even red. If it does, that's enough.
5) Add one drop of the 0871 reagent and swirl. Each drop represents .5ppm of Free Chlorine (FC). 2 drops=1ppm, 5 drops=2.5ppm, etc.
6) When the water goes clear, that's the last drop to add. I like to be certain so I put the tube on something white. If there's a tinge of pink I add one more drop.
7) Your count of drops gives you your FC level.

CC (Combined Chloramines):
8) To the SAME tube above, now add 5 drops of 0003 and swirl.
9) If there is NO pink tinge at all, you have 0 CC--that's good.
10) If there is any pink or red, keep adding the 0871 drops as before, but start the count from 0 again. 1 drop is .5ppm of CC. Do remember that if one drop is all it takes to clear the tube, your CC is .5 or LESS--it could be .2 or .4ppm. Usually, a CC of .5 is nothing to worry about.

pH is fine.
TA is high but for now, especially with your CH of 170, absolutely nothing to worry about.

CYA is low. Are you sure you ran the test correctly? Things to remember:
a) equal amounts of pool water and reagent 0013.
b) shake for at least 30 seconds.
c) hold the tube at waist level when you add the liquid.
d) Pour the liquid BACK into the squeeze bottle, then add it to the tube again to check
e) You can do d) several times over with the same liquid until you are sure of your reading.

Once you get your water clear, you can worry about lowering your T/A to the recommended 80-100 level, raising your CH over 200ppm (you have a gunite pool so 200-400 is recommended), and getting your CYA level up to AT LEAST 30ppm.

FYI: Di-Chlor powder adds CYA to your water--for every 10ppm of FC it adds, it also add about 9 or 10ppm of CYA. Tri-Chlor tabs add about 6ppm of CYA for every 10ppm of FC, but also are VERY acidic--which may hel your T/A adjustment later (see the next paragraph).

WHEN you are ready to lower T/A, you'll lower pH to 7.0-7.1 (you have a touch more wiggle room on the minimum than a vinyl pool, but 6.9 should be your absolute minimum), then aerate your water to raise pH back up. You'll keep doing this until T/A is in the 80-120 range. Aeration can come from a sprayer, kids splashing, or even just pointing the returns at the surface so they bubble. It's a ratcheting process, because T/A measurements rise and fall with the pH level and the ONLY way to raise pH without raising T/A back up again is by aeration. But that's for later.

[TCP007]

Thanks, Carl!

The instructions with the kit say to add 2 scoops of the powder. Wish I had known you only need to add enough powder to turn the sample pink/red. That must be why my FC reading was so high (?) so I will re-test this evening for sure.

I ran the CYA test properly with the correct measurements of pool water / reagent. I actually ended up filling my small comparator to the brim and the dot was still quite visible. Since the cylinder's lowest registered reading is 30ppm, I can only assume mine must be close to zero. This is not a surprise as I have known all along that my CYA is/was quite low, and definitely below 30. I didn't add it back to the sample bottle (squeeze bottle) but will keep that in mind for future tests. I know the sample is supposed to be somewhat "cloudy" after adding the reagent. It was quite obvious that my sample was not visibly cloudy.

My pool water is crystal clear now and has been since Friday. I will retest my chlorine this evening and post. Can someone tell me a good FC level at which to start adding Di-Chlor again? I have already re-supplied my floater with Tri-Chlor, which is slow dissolving.

[Watermom]

With a low CYA like you have, I'd probably wait until my FC was at 3-4 before adding more dichlor.

[CarlD]

I have to disagree with Watermom here (a rate occurrence) and say start using the di-chlor immediately as it will add nearly as much CYA as chlorine, and you need CYA.

Unless I missed something ....

[Watermom]

He last reported FC of 22.5ppm.

[TCP007]

New readings:

FC = 12.5
CC = .5
PH = 7
TA = 150
CH = 170
CYA = N/A

Chlorine results are more accurate this time. 1 scoop powder made a big difference, imo.
CYA: Same results. Small comparator was completely filled and I could still see the dot. I need to get that resolved.
pH is lower now. I tested it twice to be sure. I was surprised that it dropped that much in just a couple days.

Is it okay to start adding Di-Chlor, and will that also help to bring my pH up a little? I know it will help with CYA.

My pool is old, gunite. It has a bottom drain in diving end and 1 skimmer (in corner of deep end), and 2 returns that are both on the opposite wall (in the shallow end) right near the base of the wall. They don't have nozzles or any means of directing the water. I have no means of aeration to help raise pH, aside from keeping kids in there splashing around. Other aeration ideas are welcome!

Thanks everyone for your responses.

[Watermom]

Dichlor is acidic and will lower your pH. Plus, your FC is still too high to add more chlorine right now. Hold off on the dichlor until your FC drops to 3-4ppm.

Personally, since you don't have high pH nor high CH, I wouldn't worry about the TA. It's not all that high really. Go ahead and just add a little 20 Mule Team Borax (laundry aisle at Walmart) and use that to bring your pH up some. Start with a half a box added slowly to the skimmer while the pump is running, breaking up any clumps. Aim for mid 7s on pH.

[TCP007]

Thanks Watermom. I think we hit that "breakthrough" point with the super-chlorination I did last Thursday night. I've been reading that a non-existent CYA level like mine is an open door invitation for algae. We had a pretty good rain today, so I believe that contributed to the pH dropping. Rain also seems to invite algae. I did throw some algaecide in yesterday, so I hope that will do something even with the low CYA.

I will hold off on adding more chlorine and keep testing the chlorine levels. I'm hoping to be accepted to the site soon so I can read other posts, too. Thanks again!

[Watermom]

It is chlorine levels and not CYA levels that allow algae to grow. Also, the reason that rain appears to invite algae is because people typically don't check their chemistry as diligently when it rains. Bottom line is --- if you have adequate chlorine, you don't get algae despite rain or what your CYA level is.

What kind of algaecide did you add?

You can read other posts. If you log out first, you'll be able to see the entire forum. We had hoped to get caught up this week with getting all the new registrants processed that have come on board lately but with the passing of Ben's dad on Sunday, it is going to be a little longer until we are able to do so, unfortunately. Hope you understand.

We are glad to have you join us, however!

[CarlD]

It is chlorine levels and not CYA levels that allow algae to grow. Also, the reason that rain appears to invite algae is because people typically don't check their chemistry as diligently when it rains. Bottom line is --- if you have adequate chlorine, you don't get algae despite rain or what your CYA level is.

To be very precise, what WM means by "adequate chlorine" is the appropriate chlorine level for your CYA level, whatever that CYA level is, will keep you from getting algae.

[TCP007]

And that's what brought me here really. I need to get my CYA up. It is so low I can't measure it, and my chlorine gets used up too fast.

I added some pH Increaser last night (less than a pound; it was all I had) and that helped to bring pH up to around 7.2 I have asked my wife to pickup some Borax today, as WM suggested, so we'll give that a whirl this evening and see if that helps us get closer to 7.4

Do you folks NOT recommend using Muriatic Acid to raise CYA? I checked an online pool calculator the recommends 3 gallons of muriatic OR a little over 7 lbs of dry acid. I also read that muriatic acid won't bring my pH down like dry acid (?)

[Watermom]

No, we do not use muriatic acid to raise CYA. You either need to use a type of stabilized chlorine that has CYA in it such as trichlor or dichlor or just buy some CYA separately and add it directly. Adding it directly or using dichlor is the fastest way to add it. Trichlor is slower.

Do you already have any trichlor or dichlor on hand?

[BigDave]

Do you folks NOT recommend using Muriatic Acid to raise CYA? No, no we don't. It doesn't. CYA (aka conditioner and stabilizer) does as does trichlor and dichlor.



I checked an online pool calculator the recommends 3 gallons of muriatic OR a little over 7 lbs of dry acid.I would burn that link and never ever ever use it again. Your pH is already low.



I also read that muriatic acid won't bring my pH down like dry acid (?)Nope! muriatic acid (HCl) lowers pH and nothing else.

It's probably not a good idea to mix our advice with whatever you read wherever else.

[TCP007]

Yes, I mentioned this yesterday. I already added my floater back into the pool a couple days ago (Tri-Chlor 1" tabs). I use granular Di-Chlor as my regular sanitizer. You suggested I wait until my FC comes down to 3 or 4 before adding any. I shocked last week using liquid chlorine (Walmart had a sale for boxes of two, 1-gallon jugs of HTH liquid chlorine for $6.50!) but I don't buy liquid chlorine typically.

You suggested that people don't stay on top of their chlorine 100% the time, and that is almost certainly true of me, but I'm pretty sure I'm more diligent than the average bear. I believe I'm learning that my chlorine has been sabotaged by my low (perhaps zero) CYA levels. If none of what I just said is true, then I'm really wasting time, and have done too much online reading. :)

Thanks for listening and sharing.

[Watermom]

I'm sorry that I didn't scroll back through to reread this thread when I asked if you had trichlor or dichlor on hand. With as many posts as we answer in a day, sometimes questions/info gets repeated.

Trichlor will add CYA but will do so slowly. If you want to increase it faster, you are better off using dichlor. For every 10ppm of chlorine that it adds, dichlor will also add 9ppm of CYA

I hope you didn't think I was saying that you aren't staying on top of your chemistry. That was certainly not my intent.

You are right that not having enough CYA will cause chlorine to be lost faster.

[BigDave]

You are correct that you need CYA to protect chlorine from the sun.

I'm confused that you've been chlorinating with trichlor and dichlor and your CYA level is low - we usually see the opposite.

I don't think you are wasting your time here but any time spent where ideas like muriatic acid will raise CYA and have no effect on pH is a waste.

Stay with us. We'll get you right.

[TCP007]

Thanks, Dave.

I understand you don't know who I am, but being a pupil in this field, one cannot decipher what is good or bad intel. I'm sure you can appreciate and remember what it feels to not have all the answers? It most assuredly is not a good idea to not seek answers, which is all I'm trying to do.

I appreciate knowing you feel this site is the Mecca of all things "pool" related! I will be happy to stop asking questions asap!!

[TCP007]

WM: Part of what I do for a living is tech-related. No, I was not offended and I realize you can't keep track of every sentence that a person writes. This type of medium is chock-full of information gaps, and I completely understand it isn't perfect. I don't envy what you do here at all (understatement!) but I really do appreciate that you do it. I believe this site is a GREAT source of information, thanks to people like you.

[Watermom]

Thanks! :)

Hope we are able to help you get things straightened out. I think you are on the right track. Let us know if you have further questions and we'll be happy to try and help.

[TCP007]

I'm glad I checked into this site, and I do think I'm on the right track. Thank you!

I have been buying product from In The Swim. If we aren't supposed to post pool vendors' names/stores, please delete and accept my apology.

I buy granular chlorine from them (di-chlor) and 1" tabs for my floater (tri-chlor), as well as opening and closing kits. I'm looking at their stabilizer/conditioner right now. If you have a different recommendation for conditioner, please let me know? Thanks!

[BigDave]

Have I offended you? I didn't mean to and am sorry if I have. Maybe I'm having a grumpy day. I promise you I don't have all the answers, sorry for sounding that way.

I don't really feel that this site is a "Mecca" but I do know the information presented here is carefully considered and reviewed. We occasionally see posts that are technically wrong but they are almost always challenged. That's kinda what my response to your muriatic acid post was. I wanted to help you get it straight but also set the conversation right in the thread for someone who reads it in the future.

Please do ask questions. We want you to learn to keep your pool clean and safe with the least time and expense.

[TCP007]

I think my dilemma now is trying to figure out what my FC level should be, while I attempt to raise my CYA levels.

I just found a chart that has recommendations (originally from Ben Powell, no less!). For a CYA of 20 the target FC is 3. My CYA is most-likely lower than 20 and my FC was 12.5 as of last night, so I think I'll follow WM's and Dave's advice and hold off on the Di-Chlor (for now) and buy conditioner. With some luck, maybe my FC will start to drop in conjunction with my CYA improving.

I'm going to continue testing the TA levels, but plan to worry less about that as Watermom has suggested. (at least until I get CYA figured out)

My in-ground, gunite pool has direct sunshine practically all day long, so what is a good target CYA? I'm going to target at least 40 unless someone here advises differently. According to the chart, I'll try to maintain my FC between 3 and 5.

That's my plan going forward, pending moderation from the pro's here. :)

[CarlD]

Maybe it will help to think of those FC levels as minimums for the CYA levels. With a vinyl pool, going significantly past the shocking level MAY. bleach your liner some, but won't harm a hard-sided pool at all.

[CarlD]

He last reported FC of 22.5ppm.

So, I guess I did miss something. Don't know why I thought the FC was 0.......

[Watermom]

Aiming for a CYA of 40 sounds just fine. If you find that you are having trouble keeping chlorine in the pool, you can always bump it up some. Increasing CYA is no problem, reducing it is a whole other matter.

[TCP007]

Tested again this evening after adding Borax this afternoon:

FC = 10.5 (getting lower)
CC = .5 (same)
PH = 7.4 (thanks WM)
TA = 170 (a little higher than last night)
CH = 170 (same)

Dave: All is good. Just wanted to explain my desire to throw info at the wall, and see what sticks and what doesn't. I feel confident that this is the right board to separate fact from fiction, so please... keep it coming, and thank you.

Thanks for offering the suggestion of Borax, WM. I believe that is what pushed our pH back to good, and much more economical than buying pH plus products!

I ordered 25lbs of conditioner today (cyanuric); It should be here tomorrow. Anxious to see if I can get this balancing act figured out before it's time to close the pool.

Thanks for your patience with me. You're probably wishing I never found poolforum.com! Haha!

[Watermom]

That's a lot of CYA! But, it will keep from one season to the next. For reference, in a 30K gallon pool, it will take approximately 2-1/2 lbs to add 10ppm of CYA. Go slow with adding it so you don't overshoot your target.

You can add it a couple of ways.
1) Add it slowly to the skimmer while the pump is running and then keep your pump running 24/7 for the next 4-5 days and don't backwash or retest CYA for a week to make sure it is all dissolved.
2) Put it in an old sock and hang it in front of a return jet. Give the sock a squeeze every now and then to help it dissolve faster. Again, don't retest CYA for about a week.

Better to give it time so you can be sure it is all dissolved and registering on your test before deciding to add more.

[TCP007]

The price for the conditioner was quite a bit better with the larger quantity. I hope it lasts a couple years, too! :)

I'm going to add close to 4lbs (today, if the container arrives on time) and hope it will at least get my CYA to a measurable level (30ppm). I've had the 1" tri-chlor tabs in my floater, so I'd like to think there's a little CYA lurking in the pool, and 4 lbs gets me to 30 or at least something I can measure.

It sounds like the cyanuric takes awhile to dissolve, which isn't exactly music to my ears since I will probably need to add sanitizer in another few days. I'd hoped to have a good (accurate) CYA number BEFORE the di-chlor effected it. I'm going to do the "sock in skimmer" method with the cyanuric, since my jets are at the bottom of the pool and I don't think I can rig a hanging method in front of one. I hope the cyanuric dissolves as quick as possible via sock/skimmer.

Thanks for all your help, WM!!!

[Watermom]

Good to go slow. 4 lbs. should add an additional 17ish ppm of CYA.

And, you are welcome! Glad to be able to help. :)

[TCP007]

Update: Pool has been looking good! No signs of algae :) Surprisingly, I still haven't had to add di-chlor since super-chlorinating over 2 weeks ago. I do still have 1" tabs of tri-chlor in the floater.

Today's readings:

FC = 6.6
CC = 0.5
pH = 7.2
TA = 170
CH = 210
CYA = 40

I may get some more Borax to increase the pH a little. Do I need to worry about my high TA level? The Taylor book recommends roughly 4 gallons of muriatic to decrease it by 60ppm, which would drop my TA somewhere around 110. I could also use dry acid, but I don't want to increase my CYA now that I have it where I want it.

What do you pro's do to drop TA without raising CYA (and hopefully not mess with pH)??

[CarlD]

If your pH is holding and is stable, you can raise pH without raising T/A by aeration, rather than adding anything, including Borax. Since your CH is near the bottom of the range, but still in it, I personally would not want to mess with it by adding acid.

IF you decide to try to lower T/A I STILL wouldn't use Borax. Raise pH, again, using aeration (splashing, sprayer, pointing the return at the surface). Then add acid to lower pH, no lower than 7.2. T/A should come down with it. Then aerate some more to raise pH without raising T/A. Keep doing this till the T/A is under 125.

[TCP007]

I've read your suggestions about aeration raising pH, but my return jets (2) are in the bottom of the shallow end (on wall, right along the bottom) and they do not have nozzles. They are open holes. There used to be plates over them, but the fixture they screwed into had rusted out. I don't know when this pool was built... but it's old! I can't imagine utilizing the returns for anything that might promote aeration. Kids would be my best weapon, but the pH seems to be holding steady at 7.2 these last couple weeks. I'm not sure they are helping (or swimming!) enough, so if you have any alternative methods of creating aeration... I'm all ears. I will try to think of something as well. Thanks, Carl.

[Watermom]

Can you screw anything into those returns? Maybe make a contraption out of PVC that screws in, has a 90 degree angle and shoots water out at the top of the water surface or something like that?

[BigDave]

Perhaps a submersible pump with an outlet hose above the water or maybe even a shower head?

[CarlD]

Here are 2 examples of a simple, inexpensive sprayer that makes aeration easy:

http://www.ebay.com/itm/like/111389606954?lpid=82

http://www.ebay.com/itm/New-Wonder-In-Ground-or-Above-Ground-Swimming-Pool-Waterfall-Fountain-/131175602665?_trksid=p2054897.l5660

I have something similar but I haven't had to use it in years. I think I paid $20 for it.