Mustard Algae problem or not?

[keastman]

Ben, thanks for your input. Yes, I'm using the K2006 kit I got via this site's link. A couple of years ago the pool store (one that used photmetric analysis which I don't trust) said I had very high phosphates and wanted to sell me some junk that I didn't buy. At that time, the suggestions on this site said if I wan't having problems don't worry about it. I'll take a sample to Pinch a Penny tomorrow and have the test for phosphates. They use titration mehthods, so I'm assuming are more accurate if they have a titration test for phosphates.

As to the floor inlets, the only other inlet for the pool is the venturi skimmer which is limited in return volume and the SWG enters through that, so I won't be able to cut off the diverter and cap the lines as you suggested. I do think that these runs could be at the root of the problem if it is mustard algae Starting last fall some of them broke down in a few of the zones and the cleaning heads popped out. So, those in those zones, all the water enters from the blown out head and the water in runs to the other heads in the zone probably doesn't move a lot since the remaining heads in the affected zones don't activate. Perhaps that's where the algae hides out. The heads are also the only returns for my spa. So, my plan will be to pull out all the heads in the pool. The zones will still operate independently, but every return in the zone will then have water flowing through them. I may also get an appropriate sized bottle brush and try to clean as deep as I can get into each opening. Then I'll jack the chlorine up as stated earlier.

I'll report back on the phosphate results.

[PoolDoc]

sounds good.

[keastman]

OK Ben, I got the rest of the in floor heads out today and cleaned their outlets as well as possible with a brush. I had the water tested for phosphates and as I remember it was high. 500ppm or more. I think it was the last color on the scale they were using. So, do you think the phophates are feeding the algae problem. Of course they wanted to sell me their phosphate remover. I figured I'd wait until I hear from you. Eventually I'll need to fabricate a cap for those floor outlets with small holes in them so that no one gets a toe or hand caught in them.

If you recall my other thread in equipment, I'm also about to replace my 12o sq ft cart filter with a 320sq ft one and new pump, but am thinking I need to clear this up first. I've also got high alkalinity and high Calcium hardness, don't know if that's making anything worse also.

My FC was 16 this morning with a CC of less than 0.5. The yellow dust is now blue grey, water is clear with a slight haze. I'm brushing daily. Typical for this point of my shocking. My plan was to put the Chlorine to 25 to 30 now for 3-4 days. Where would you suggest I go from here with the phosphates etc.

Thanks again for your help.

[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.