Filtering out dead Mustard Algae

[DWSPool]

I haven't posted here for a while because the information on this site is so thorough and accurate that I rarely have needed to ask questions. But, now I'm up against a lee shore.

We are having a wedding at our house this coming weekend for my daughter, with 100+ folks coming from all over, which includes a wedding pool party. Now, an outbreak of mustard algae (powdery when brushed, vibrant yellow/green in streaks and spots) - normal shock didn't eradicate it; got it up to MA level for 24 hrs, then MA coming back after chlorine coming down, even though CC has been non-detectable.

I still need to clean out the pool light cavity; but the main question is: should a sand filter be able to filter out dead mustard algae? The sand filter has worked fine in the past, but it seems to be letting MA (or dead MA) through, since streaks of deposits are settling downstream of the shallow end return, and the pressure is not increasing, which it usually does quite a bit after running the vacuum.

Any helpful suggestions are greatly welcome. Only 5 days til WD (Wedding Day)!

 

[JasonLion]

First, I just want to clarify that high FC levels will temporarily get rid of mustard algae, though it tends to come back as some as the FC level goes back down to normal. If your "mustard algae" continues to accumulate while FC is high, then it isn't mustard algae and must be something else.

A sand filter should be easily able to filter out all of the dead mustard algae. From your description, it sounds like the filter is not working correctly. The two most likely possibilities is that there is a problem with the main valve which allows water to bypass the filter, or the filter has become channeled. There is a good post on fixing channeling here. You might also want to check the main valve to make sure it doesn't need new gaskets/o-rings.

 

[Butterfly]

After you check out Jason's recommendations, you can try adding a little DE to the sand filter: pool-school/add_de_to_a_sand_filter

 

[DWSPool]

Thanks for such quick responses! - good suggestions all - I will look into the channeling possibility first, but the gasket/o-ring on the main valve is aso a real possibility since this is an old filter and valve. The DE option is also a good suggestion - turns out, we have some of that lying around the house. Thanks again Jason and Butterfly!

 

[elwood58]

Thanks for such quick responses! - good suggestions all - I will look into the channeling possibility first, but the gasket/o-ring on the main valve is aso a real possibility since this is an old filter and valve. The DE option is also a good suggestion - turns out, we have some of that lying around the house. Thanks again Jason and Butterfly!

Make sure your DE is for Pool use, not Garden use. Also make sure and follow directions for how much you add.