Pink Slime and Biofilm

[OasisSeeker]

After my fourth iron treatment, which requires running at a low FC level, my worst fear was realized - my pool developed some pink mold, even though I had plenty of Polyquat 60 in the water at the time. The pool was never completely without sanitizer, but I have a very high CYA (my plan all along was to do a partial dump at the end of the season to correct this), so I guess running below 3 ppm for several days, even with algaecide, caused the problem.

The first thing I did was brush off all visible pink mold (I know this is actually bacteria and not algae). It appeared on my steps and around the light fixture, also in the skimmer and beneath the bottom ladder rung (didn't catch the ladder issue right away). Then I shocked, vacuumed, backwashed, and am continuing to shock and brush.

With a CYA somewhere between 80 to 100 (I have a hard time doing this test and seeing when the black dot disappears), my shock level is probably in the low 30s. I have been trying to maintain this level, but it's been difficult because of work, and when I come home, the FC level is back in the teens by late afternoon.

So I'm off work today and am maintaining a level of 35. Seems to be holding right now. I have not seen any actual pink in over 24 hours. However, there is one spot along the liner seam, on the pool floor in the shallow end, where a white film or powder keeps appearing. Even at FC 35 ppm. I have to keep brushing it off. The first time I saw it a few days ago, I thought it was DE powder, but on close inspection, it seems more gel like. Also, the first time I saw it, there was some pink attached to it, so I assume this is either biofilm or white mold - I don't know if there is a difference. Now the white stuff keeps coming back with no pink on it and it brushes away and turns to dust. It is about 4 or five inches wide and maybe 15 inches long. Does anyone know what this is or why it keeps coming back to the same place, within hours after being brushed up? There is also some powder like substance appearing nearby all along the seem of the liner. Again, this brushes up easily like dust. Also, when I brush the liner, this seems to create dust clouds even in places where I don't see anything at all. Like there is invisible dust or powder everywhere.

Is it possible this could be DE powder? A few years ago when one of my filter grids had to be replaced, the powder appeared in the seams like this. I have been putting the poor filter through **** this season - lots of backwashing between metal treatments.

Thanks.

FC 35
CC 0 to .5
Ph 7.2
TA 140
CYA 80 to 100 ?

 

[OasisSeeker]

I'm also wondering if I put so much granular chlorine in the pool to get at my shock level that it's no longer dissolving? Although the deep end is quite cloudy now from the shock treatment, there is definitely some kind of powdery substance lying in the corners that brushes up - the places where I always have to brush after adding any type of powder. Is it possible to have oversaturation of calcium hypo? I have been using that in conjunction with liquid bleach to get up to 35 ppm FC.

I also just had to backwash again. Filter was 8 over normal. There is no debris in the pool, and I have not vacuumed up anything. Not sure what could be gumming it up.

 

[Butterfly]

Did you test the CH?

Low CH with vinyl is okay, but too high CH can cause problems.

Any time CH is added, it can cause cloudiness. But, your cloudiness is probably dead bacteria/algae/organics waiting to be filtered out.

The filter will need to be backwashed each time the pressure rises about 25% above clean filter pressure.

 

[OasisSeeker]

CH is 50. I spent a lot of money my first two pool seasons adding buckets and buckets of calcium, only to have it dissipate. I don't know where it goes, but my water obviously can't keep calcium and, as you point out, low CH shouldn't be an issue with vinyl. However, I do have a heater - not sure if low CH can be harmful to the internal workings of the heater? Could this have led to my iron problem that started this mess?

After three solid days of 30 plus FC, I decided to let the level drift downward and try to stabilize at a more reasonable level. I'm at 24 FC right now and the water is clear. There is still dust when I brush. I vacuumed the entire floor really well earlier tonight, and other than the spot in the shallow end where a mass of gray keeps forming no matter how many times I brush it away, I don't see anything on the liner. But still, if I brush in the shallow end, there is dust. Odd, because you can't see anything lying on the liner, but the brush creates a cloud of dust, from what, I don't know. DE powder? (unlikely, because the last time I had a bad DE grid, I could clearly see a lot of brownish/gray powder all over the bottom of the pool), undesolved chlorine powder? dead bacteria or mold?

My plan is to try to stabilize the FC at 10 to 12 ppm. If I can get it to stay there on its own and no more pink shows up, I figure I may be OK. I know I am supposed to do the overnight FC test and try to stay at shock level, but I am worried about destroying my liner. Hopefully, I can do a partial drain sooner than later and fix my CYA predicament.

Any ideas on what the invisible dust is in the bottom of the pool?

 

[OasisSeeker]

DE filter is leaking from the bottom. I have pool tech coming on Tuesday or Wednesday, soonest they can get here. I'm hoping the gray powdery substance is due to a torn grid or some other issue with the filter. It keeps forming along one entire seam in the shallow end and then there is a larger patch of it just before the drop off into the deep end. Seems to be a logical/natural place where the water flow would cause debris to settle.

I can't find any photos of white mold/algae. Most people talk about it floating on the surface and looking like tissue paper, or I have seen images of white mold inside filters. I wouldn't think white mold would keep forming in this same exact place over and over again almost immediately after I brush, but I have to say I am very worried about it this stuff I have in the bottom of my pool being mold or biofilm setting in. Does anyone know if biofilm would behave this way?

There was also a little bit on my steps. It is kind of sandy. It disappears/dissolves as soon as you touch it. That's why I think it is DE coming from the return jets.

There is still a strong chlorine odor near the pool. Is this normal for a FC level of 17, or does that mean there is a problem? The water samples themselves do not have an odor and the water is now clear.

 

[OasisSeeker]

Just in case anyone was out there wondering, the pool tech came today to service my filter (I admit I am afraid of my own DE filter, sad but true). Turns out, it was filled with pink slime, the bottom manifold was cracked and, as suspected, several grids had holes.

So with new grids and a clean filter, my FC level is now stabilized (yay!). Holding steady at 12.5 for most of the day, and I'm going to leave it there for a few days, just to be on the safe side. I vacuumed up the DE powder (yes, it was DE powder) in the bottom of the pool, and the water is crystal clear.

Confusing when you have two separate pool tragedies going on at once. DE filter poops out during a pink slime outbreak. What are the chances?

Pool store recommends Pink Treat. If the pink monster returns, I may consider it. Could still be pink hiding in the lines, right? Has anyone had luck with this? For now, I'm not planning to add anything wacky to my water for the time being. Even If the metal stain comes back, so be it. Right now, after shocking at 35 ppm, there is only light staining on the top step, which is kind of odd. I expected to come out of the uber shock experience (35 FC - yikes) with a bronze pool. A few weeks ago, raising my FC to 4 created major iron stains. We'll see what tomorrow brings.

Pool store also says they will not assist with a partial drain to lower my CYA, because it can harm my liner. I was hoping they could help coordinate a truck bringing in water. I know I can't do a full dump, but I was hoping to go down at least a few feet and then get it refilled right away with truck water at the end of the season. Apparently pool store has lots of pools with high CYA and it's no big deal and they insist I should run at FC 2 to 3, despite stabilizer level.

Well, after this experience, I can attest that my shock level is too HIGH, obviously the result of a high CYA. It was only by getting my FC up to 35 and holding it there that I was able to somewhat stabilize my chlorine levels through this pink mold debacle. If I was able to get into my filter sooner, it may have done the trick. Clearly, a lower shock threshold is desirable when you have to super shock out algae/mold/bacteria, etc.

I guess I will research the trucked in water on my own. My hose pressure is not very good - it takes forever to add even small amounts of water.

Well, if nothing else, I learned how to remove my ladder, and I'm glad I did. There was LOTS of pink mold hiding under the bottom rung, and no way I would have been able to clean it without taking the ladder out. Thank you, YouTube, for teaching me about "the wedge."