Algae keeps coming back

jandersen13

Well-known member
Feb 27, 2015
88
Grand Rapids MI
I have a Dolphin M400. I’ve run it everyday the last few days, if not once, twice. But it still seems there is always the dead algae in the same place on the floor and steps by a return line. Is the filter not filtering it out?

The water is blue and clear. But just a few spots of the dead algae. And then in the deep end when I brush an angled wall it kicks up the “dust”. So do I still have active algae?
 

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mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
21,263
Laughlin, NV
You are still clearing out some of the more resistant algae. If you have a light niche be sure to check that. Also any steps, weir door, skimmer, etc.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
21,263
Laughlin, NV
What is your FC? pH testing with FC above 10 ppm is not valid.

pH can be raised by aeration. What are the pH and TA test results?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
21,263
Laughlin, NV
I would not do anything with pH or TA.

Stay at your SLAM. No need to test anything but FC during it.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
21,263
Laughlin, NV
Not really. Winter helps it, but that is no good for pool use!

With the elevated FC for your SLAM, your loss from UV is higher. Get the SLAM done. Then use target range FC.
 
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Katodude

Silver Supporter
Aug 22, 2017
268
West Palm Beach/Florida
So a couple of things I just noticed. I think you said your new CYA level is 50, if that is the case then your SLAM level is 20 for FC. If you keep you FC lower than that the SLAM will take longer. The more often you adjust your FC to 20 the less time the SLAM will take.

Also when running your M400 make sure you are using the fine pleated filters. That will help you clean our the deal algae.
 

Casey

TFP Expert
LifeTime Supporter
Apr 16, 2007
10,865
SW PA
Also, your water may appear clear to you but it is not. When your water looks like this, you can do an OCLT. You want to see it shimmer like a Diamond when the sun hits the water.
 

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jandersen13

Well-known member
Feb 27, 2015
88
Grand Rapids MI
Things are progressing and looking good now. I think it’s just a matter of filtering to clear the last bit up.

We are getting hit with some heavy rain right now. What’s my best approach after this to not screw it up?

Alkalinity and PH tests won’t be accurate right? Any suggestions on how to test / proceed today?
 

IceShadow

Gold Supporter
Jun 8, 2019
1,031
Milwaukee, WI
If you can test in the rain (no lightning) then you can keep testing and adding. Rain won't really affect much. Even if it gets high enough you have to drain some off it's going to be pretty minimal compared to the total pool volume.