Help! SHOCKED & MUSTARD SHOCKED but it's still here!!

[aesweeps]

I am literally at my witts end here and hoping someone here has some advice. I use 8.25% bleach, CYA is at 30. Been seeing brown spots in my pool for a few months now, I sweep it away and it disappears until the next day or two. During this time the chemical levels were all good--CYA 30, FC 2-4, CC 0, PH 7.5, Alkalinity 90. From what I read I determined the the brown spots to be mustard algae. The brown stuff was not gritty like dirt or sand, it was not pollen, if I touched it it would quickly disappear. It's normally found in the shallow end in different areas. I started SLAMing my pool Friday evening keeping FC levels at around 13 to 14. Pool finally passed the OCLT test yesterday on Sunday morning. I then raised to Mustard shock level of 19. A few hours later I checked and it dropped to 15 FC so I added more bleach and kept it at around 19 the remainder of the day. Today (Monday) I went and looked at pool and saw the little brown spots starting up in my pool once again. I don't understand, my pool is still at high levels and it's back already!! I have spent tons of money on this weekends SLAMing alone, and feel it was all for nothing. Any suggestions?? Thank you in advance.

25,000+ gallons
vinyl in-ground pool
CYA 30
FC 19
PH was normal at 7.5 but now high after all the SLAMing
pool is in full sun, temps stay in the 90's everyday usually all summer long.

 

[Texas Splash]

Where is your pool water from? Any chance it's from a well?

 

[aesweeps]

no well. it's city water

 

[Texas Splash]

Well, the one thing that keeps coming back to me as I read & re-read your initial post is how you've had this problem for months. It sweeps away relatively easily, then returns in the shallow end. You also maintain a relatively low-scale CYA and FC level. If we rule-out metals in the water, and you doubt it is dirt, then I return to algae. I know that would seem odd if you just passed the OLCT Sunday morning, but if your pool is always struggling with the sun/heat in yore area, coupled with maintaining CYA and FC on the lower end of the scale, perhaps that's why? Also important to note is that some folks have issues with poor circulation. That, coupled with everything else I mentioned can lead to some specific "trouble spots" for some pools. Have you tried adjusting your return jets to those trouble areas to see if it helps?

 

[tim5055]

Just because you originally passed an OCLT did you still see the spots? What were the CC?


If you suspect mustard algae you SLAM until all three are true

Pass OCLT
CC less than .5
Water is clear - this means you don't see any algae, living or dead

When all three are passed, then raise the FC to mustard level for an additional 24 hours.

The drop from 19 to 15 doesn't worry me, that could be normal loss to the UV of the sun due to your high levels.

 

[aesweeps]

I have not tried adjusting the jets but will, although the water flow and movement seems to be pretty good. I really dont think it's dirt because it is not gritty at all, and pollen I guess this may be a possibility--although I'm not really sure how this would look in a pool..when I barely touch the stuff it just quickly disappears leaving no trace of anything in its place which made me think it was mustard algae. I have not tested for metals yet, but will research on this site to find the instructions to do so.

Just from things I read and with our normal hot temps here in the Charlotte, NC area, I always felt the CYA and FC were on the low side. My goal was to increase the CYA to about 45 after all of this was squared away, and keep an FC level of about 6-8 FC. But I just don't know what to do now after finding the brown stuff again. I'll get to looking into testing for metals in the water.

 

[duraleigh]

Skip the metals test. A picture of the "brown stuff" will help a lot but I can almost promise that's dead algae. You have never eradicated the algae properly so it is still in your pool. You kill some of it (that's the brown stuff) but not all so it simply grows back.

You need to SLAM the pool properly. Read the article and follow it to a T....no variations, no shortcuts. You will use a lot of chlorine to keep your FC up high enough long enough but that's what it takes......no half-hearted attempts.....SLAM your pool.

 

[Texas Splash]

If you do decide to test for metals (i.e at the pool store), don't take a water sample directly from the pool because the chlorine messes with the test. Get a pure sample from the source (water spigot) so its chlorine-free.

 

[ping]

Are these spots in shaded areas of the pool? If they are in sunny areas then it most likely is not mustard algae as it grows in shaded areas of the pool.

 

[aesweeps]

tim5055, prior to Mustard algae shocking, the pool did pass the OCLT test no loss at all overnight, the CC was at .2, and the water was somewhat cloudy but I could still see the bottom, but there was no brown spots present at all during this time. I figured the cloudiness was just from all of the bleach poured in during this time. FYI, I'm using the Taylor test kit for my testing which includes the R-0870 powder, R-0871, & R-0003.

 

[Texas Splash]

But typically, I don't believe you would see stains from metal just brush away so easily as you are describing, so it's probably more in-line with algae.

 

[aesweeps]

pool is in full sun all day. it is enclosed by shrubs, and trees are located in the four corners, but sit about 6' out but they don't really provide any shade.

DURALEIGH, are you suggesting the normal SLAMing again which the calculator tells me to do at 13 FC or the Mustard Shock level at 19?? I will take pictures again when they reappear. I wish I would have done so this morning before I swept them away but did not.

 

[Texas Splash]

aesweeps, a few quotes from experts I thought you might to compare to your situation:

Green algae usually floats in the water and turns the entire pool a murky green. Mustard algae is a yellow green color and grows on the walls and floor mostly on the shady side of the pool. Pollen and dirt tends to accumulate in drifts on the floor in places with slower circulation and can often look fairly similar to mustard algae. There are occasional exceptions to all of these rules, green algae sometimes grows in mats on the walls or floor, mustard algae sometimes floats in the water, etc. So positive identification isn't always easy.

Mustard algae will spread and grow up the walls of the pool if you don't shock the pool. Dust/pollen will keep re-appearing, but will never accumulate on the walls of the pool. If you do shock the pool, mustard algae will mostly disappear as long as you are at shock level and brushing occasionally. Dust will continue appearing at the same rate when you are at shock level.

Gritty is usually dirt; squishy is usually pollen; slimy is usually algae.

 

[tim5055]

tim5055, prior to Mustard algae shocking, the pool did pass the OCLT test no loss at all overnight, the CC was at .2, and the water was somewhat cloudy but I could still see the bottom, but there was no brown spots present at all during this time. I figured the cloudiness was just from all of the bleach poured in during this time. FYI, I'm using the Taylor test kit for my testing which includes the R-0870 powder, R-0871, & R-0003.

Nope, clear water means clear. You stopped the SLAM too soon.

Keep the pool at shock level until all three tests are passed.

Don't feel you are alone, lots of folks stop too soon and have to go back.

As to your algae, is it on the walls of the shady side of the pool? That is where you generally find mustard, but it is extremely uncommon.

 

[aesweeps]

tim5055, no I have Never seen the brown stuff on the walls, the pool is in full sun during the day no shade until night time. I managed to find a few more brown spots, pictures are attached, not the best pics but the the best I could get. Also a couple pics showing the clear water in shallow end and slightly cloudy in deep end.View attachment 41136View attachment 41137View attachment 41138View attachment 41139

 

[ouachita]

Your deep end should be as clear as your shallow end. That is pretty cloudy.

 

[aesweeps]

I thought it would be normal for it to be slightly cloudy from the many bottles of bleach I put in over the weekend?? when I sweep a light cloud of white dust comes off the floor of the pool, assumed this was due to the chemicals and dead algae. does cloudy water mean algae is still present?

 

[Texas Splash]

Cloudiness won't be from the bleach. Cloudiness is likely from suspended organic material or dead algae. Stay with the SLAM and keep that filter going to help filter-out the junk.

 

[aesweeps]

thanks everyone for your help!

TexasSplash, thanks for the info regarding the cloudiness of water--that definitely helped me understand a little better, also for the quotes from experts you listed earlier!! I will continue SLAMing until water is crystal clear. Wish me luck!

 

[rnjw]

I was having similar issues until it dawned on me that the filter must be accumulating the algae and pollen. When starting the pump one day we noticed it spewing yellow, my suspicion was confirmed.
Just spent a couple of hours hosing down the 4 cartridge filters which were heavily filled with a year's worth of particles, bugs, organic matter. Here's a photo showing the partially cleaned filter:
I fully expect to be back to a crystal clear pool of water after I finish, sweep and chlorinate, probably slam.

It's been in the 85-100 degrees here in Pittsburg, CA for a couple of weeks. Pool temp was a low of 84 (we have a bubble cover at night) and has been as high as 92.