My pool looks like then when I run my pump. Before turning on pump, the floor was clean. If I run a brush over this, it puffs into a dark cloud, and the floor will be clean again. My FC is 8 (a bit high bc I added chlorine yesterday) CC was 0 today. 
What is this
- Thread starter scout123
- Start date
My first thought is dead algae since I opened to a yucky mess, but I don't understand why it only shows up when I turn my pump on. If I brush through it, it will disappear in a cloud and not settle back on the floor. I left my pump off all day yesterday and last night and went out this afternoon to turn it on. Floor was clean. Ran the pump for about 2 hours and floor looks like the above.
It is likely algae. You should perform the SLAM Process. You will need a FAS-DPD test for chlorine. What testing are you using?
I have a Taylor K-2006 test kit. I thought algae, but was surprised the my CC was 0??
It's probably mustard algae. That type is particularly difficult to eradicate.
Algae does not cause CC.
SLAM until it's gone.
Algae does not cause CC.
SLAM until it's gone.
hwy17
Well-known member
Check your cya to start, if it's too high you're going to need to drain and slamming first is just a waste.
It's probably mustard algae.
This type can sometimes pass an OCLT because it does not react to chlorine like regular algae.
A full proper SLAM with mustard algae protocol is indicated.
This type can sometimes pass an OCLT because it does not react to chlorine like regular algae.
A full proper SLAM with mustard algae protocol is indicated.
OP, are you running your SWG when you run your pump? If so, it makes sense that any live algae is dying and settling due to chlorine in the water.
Also, when is the last time you backwashed, and how do your hoses look?
Also, when is the last time you backwashed, and how do your hoses look?
This type of mustard algae is olive green with some brown and yellow tints.
It looks and acts like really fine sand.
There is also a different type that is a yellow color and it sticks to walls and floors.
It looks and acts like really fine sand.
There is also a different type that is a yellow color and it sticks to walls and floors.
I'm not running my SWG yet. I just reconnected my pump 5 days ago. About a week or so ago, I had drained about 2/3 of my pool water so I could patch a slice in the pool wall. There was a lot of yellow on the wall just at the water line. I thought it was pollen. I live in GA and everything is yellow this time of year. I brushed the walls down. When I drained my pool down the water was yucky so I just dumped a gallon of chlorine in without testing anything. Pump wasn't hooked up yet. I swirled it around with a brush. Dumped another gallon the next day. Then it began raining and rained enough to fill my pool to half way, and I finished filling with hose. I hooked up my pump. I backwashed my filter. Water was brown. I backwashed until clear. Rinsed and ran filter. Poured in more chlorine (without testing....was being lazy). Came out to find pool floor covered. I thought it was sand. (suspected a crack in lateral last year but couldn't find one, though I consistently got a bit of sand in my pool) Brushed it and it went away. (cloud of brown, then disappeared) Turned pump off before going to bed. For 2 days we had a cold front move through and I didn't do anything outside, except dump in gallon of chlorine each day. I didn't turn on pump those 2 days. Floor stayed clear these 2 days. Went out yesterday and pool was crystal clear and floor was clean. I backwashed filter again. Again I had brown water coming out from backwash. I backwashed until clear and rinsed. Turned on pump and 2 hours later floor was covered with this again. Finally tested water. No detectable CYA (could still see dot when full), FC was 8 and CC was 0.
Will start proper SLAM today. Not planning to start SWG until after I pass OCLT. I generally like to get my water balanced first with liquid chlorine, and start my SWG to keep it balanced.
Thanks. First time since having a pool that I'm having to do this, and it's because I didn't bother to close it properly.
Yeah, you need to start testing and measuring, and follow SLAM. No lazy!