I have been battling what I believe was mustard algae, since late June 08. I came home from vacation to find chlorine about zero and brownish powdery substance all over one side of my plaster pool. I brushed and shocked only to have the powder substance come back a couple days later but not as bad. I treated with polyqort 60 and shocked some more. A water test during this time showed high level of phosphates around 1000 and CYA over 100. I started using non-stabilized shock and treated for phosphates. Water had been clear but unable to hold FC, and the brownish powder stains kept appearing around 2-3 days if I did not brush. After brushing I could still see slight brownish stains in the pores of the plaster, while snorkeling underwater. They would get a little lighter by scrubbing with wire brush or stone but will not go away. They are only on the sides, but few places close to bottom.
So, a couple weeks ago I consulted my pool store and they advise to treat with yellow treat, which I did two treatments and supershock to no avail, alage like stains came back, and pool still couldn’t hold FC and CYA was still running high, even after draining a little and refilling 90-100.
Since that didn’t work they advise to try Banish fro Bio guard since it is copper base and would kill other algae as well. Did that last Thursday, along with shock, and was also told to raise chlorine levels to at least 10 and hold till stains algae disappear. However, after about 20 pounds of Bio Guard Burn Out my pool will not hold FC and CYA is still at 110. I also should mention that I have quit using pucks. I am unable to even get my water up to 1ppm chlorine let alone 10. Plus my water turned lime green after all the shock, but then went to milky blue by next day and by third was pretty clear.
Another pool store lady who actual came out to look at pool for free and as not been trying to sell me stuff advised just to be patient and let everything filter out. Then start liquid chlorine treatment tonight (3gals), and take reading tonight and in morning to see if water will hold FC. She doesn’t seem to be worried about the CYA levels having any affect on the pools ability to hold chlorine or any of the other junk that I have added to pool. Says if pool doesn’t hold over night that we will try non-chlorine shock, to break whatever is locking chlorine.
I am looking for any help to identify my algae and/or stains, and chlorine problems. This is my 4th year for the pool and have never had any problems, like this.
Here are my readings as of this morning. My pool is roughly 27,500, with D.E. Filter, had nature2 cartridge but took it out a couple weeks ago, also have electric heat pump.
Attached is a picture from above the water of some of the spots along the water edge this was take last week, after two days of no brushing.