Black mold-I think

Jul 16, 2007
64
Indiana
I found a bunch of what I think was black mold yesterday around my skimmer frame. I took a tooth brush to it and got a black cloud in the water. After the cloud dissipated I saw a lot of black particles floating around. On the plastic frame of the skimmer was a greasy black film which really didn't want to come off. I slammed the pool with chlorine. When I got home from work this afternoon I tested my chlorine to see where I was...it was all gone. I then tested my CYA, it too was reading zero. i went to the pool store and they told me I do have CYA, that my 'slam' has made reading it, temporarily difficult.

I decided to take a look at the filter cartridge, it was covered in mustard algea like I had never seen before. I cleaned all of the plumbing I have access to and replaced the cartridge with a spare. I also brushed the pool. While I was doing that my wife was spraying the cruddy filter down. She observed black mold in some of the filter pleats. I've heard about 'acid washing' the cartridge, is this the best way to really clean a cartridge that has mold or is there a perhaps less caustic method? Right now the filter is soaking in a cascade bath.

After all of this the pool seems to be holding chlorine again, thankfully.

Thanks all!
 
How are you testing your water and can you provide a complete set of test results? Also, do you clean your filter regularly?
 
I usually use my TF100 test kit. I also occasionally take a sample to the pool store for comparison. I've done both this week. I would say I've cleaned my filter cartridge more this year than ever before. We've had a massive bunch of cottonwood blowing around this year and it kept plugging things up. This is the first time I've ever seen mustard algae anywhere in my pool except behind the light. This summer is way out of the norm for us, I've only been in the pool twice and nobody else has gotten in. Some medical things going on, and it's been chilly and rainy.

Here are the numbers from the pool store from yesterday:

Total Chlor 8.0
Free Chlor 7.0
PH 7.8
Alkalinity 185
CYA 15
TDS 3400

I'm planning to check and clean the filter again tomorrow. Once that is done I need to get some CYA added (I checked this not long ago and it was 40-45- not sure what happened to this). I also just put together some PVC parts and made aerators for three of my wall jets, which I plan to run after I lower the PH to about 7.1 or 7.2 to lower my alkalinity. The black stuff around the skimmer looks to be gone now, but I'll keep an eye on that. Any suggestions?
 
The numbers below are from a tests I did the day the black cloud stuff was coming out around the bottom and lower sides of the skimmer.

CC .5
FC 1.5
PH 7.5
Alkalinity 200-210
CYA 0

I took the toothbrush to the bottom edge of the skimmer again yesterday. More of the black stuff came out. I'd like to take the skimmer frame off to see what's behind it, but don't want to break the seal to the liner

The water is holding chlorine now. I added two pounds of granular CYA yesterday.

I'm fairly satisfied the water is doing ok now, I'd just like to know what the black stuff is. Have not seen it in my pool before.
 
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