Mustard Algae problem or not?

[PoolDoc]

I almost can't believe I'm saying this, but with 0.5 ppm phosphates, it might be worthwhile to try using a remover. I'd recommend wait for the new filter, though. The removers cloud the pool badly, and it will clean up better with the larger filter.

Meanwhile, keep the chlorine high.

If you want to do so, adding borax to reach a 60 ppm level would also help. On a 23K gal pool, you'd need about 100 lbs (22 boxes of 20 Mule Team borax) plus about 6 gallons of muriatic acid. Borates at that level do seem to inhibit mustard algae, from the reports we've seen.

PAC floc will also remove phosphates, if you use them as a drip feed ahead of your filter, and clean the filter before the floc can escape. But you'll DEFINITELY want the new filter first.

[keastman]

Thanks, I guess I'd better get to work on plumbing in the filter then. Is there any type of phospate remover that's better than another. I usually deal with Pinch a Penny for chlorine and CYA, so I'd probably get what they carry, unless there is one that works better. Looks like this could be the summer for borates also if that will help. Can you tell me if that effects the taste of the water at all? Not that we drink it!

I also remembered that I haven't used the spa in well over a year, so I dumped a bunch of chlorine in it and switched over the returns and drain to spa to cook the jet pipes and spa return pipes for a while. I've yanked my non functioning heat pump and we wont' be using the spa other than to look at. Perhaps I should slightly open the drain and return for it so pool water is always moving through sth spa piping. Or would just switching the valves weekly for a few minutes to the trick.

I'll let you know how it's going once I get the plumbing changed around.

[keastman]

OK Ben, I've been running my Free Cl between 25-29 for about 5 days with no CC and an overnight loss of 1-2ppm at most. The yellow has been gone for that period, only a small amount of clear dust on the bottom.
I'm about ready to stop the liquid chlorine and let the level settle while I continue brushing and vacuuming.

So, I tested my CYA tonight and it is down to 40 or just a bit under that when it was 50-55 when I started jacking up the Cl. My question is, will the high Cl levels interfere with the test or burn off CYA? I know you've written of the biofilm consuming the CYA, but I can't believe I'd have a viable biofilm at those Cl levels. There have been no significant rains or water added to the pool in this time frame. My pool does usually go down to "0" cya through the winter, so I figure that may be biofilm action.

[keastman]

Watermom, could you ask Ben to look at my last post and see what he thinks of the missing CYA. I've now stopped adding CL, still have the SWG off and am letting the Cl drop. It's come down from 28-18 in 48 hours with only the pump running. Water is still clear. I'm planning on switching back to 8 hrs a day on the pump and starting the swg again tomorrow. I will need to add more CYA again but am confused on where it went. I'm going to test it today and probably put a sock full in the skimmer. The pool is shaded for half the day.

[PoolDoc]

The CYA test isn't that accurate -- technically, if you get a reading of 50 ppm, both 40 and 60 are in the range of error.

When you add in the fact that high chlorine slowly breaks CYA down, and the fact that you may well have had some water loss during cleaning and such (typical, through of course, I don't know that it happened in your case)

[keastman]

Thanks,

I guess I'll continue to let the Cl fall and then add CYA to get back to the 60+ range for my SWG when I turn it back on. Then keep my fingers crossed that the yellow scourge doesn't re-appear.