pool opening algae or stains

May 4, 2012
10
Pool was opened 7 days ago. due to a warm and wet winter it was black on opening. 7 days later and lots of work the water is pretty but the steps have a brown/tan maybe a little yellow stain or growth on them. There are a few places on the floor and wall of pool also that are tan to yellow looking that I can not get rid of. They will not brush off. Wednesday evening at 8pm using the pool calculator I put in enough bleach to raise the chlorine to 24. Due to work I was not able to test pool again until Fri at 4pm. Chlorine reads .5 with no change in markings on steps but some of the wall may be slightly better. Still will not brush away. Is this Algea or a stain? If it was just a stain wouldn't I still have some chlorine left less than 48 hours after raising it that high? No rain since last shocking and temps in upper 80's. I have been adding 5-6 182oz jugs of bleach every evening since opening. Seems like I've used a lot of bleach to still have markings left. Do I continue on this same path or do I need to try something else? Any help would be appreciated? Pool is gunite approx 25560 gallons and cartridge filters that have required cleaning 4 times since opening. My ph is 7.6 and TA is 100. Calcium hardness was 240. Pool store said my cya was 60 although when I tested it a few days (right after opening) before the store did I got a reading of less than 30. Also I have been able to keep 5ppm over night but not 24hrs. 5ppm is as high as my test kit reads. How long should I strive to keep chlorine at or above 5ppm?
 
Well, I'm still guessing a little but it looks like those stains are either tannin stains from all the organic junk that was in the pool or possibly, calcium stains.

I would test for organic stains first. Get a chlorine puck and hold it directly onto a stained area for a few minutes. If it removes it or lightens it a lot then the stain is organic.

If the puck has little or no affect, crush up some cheap vitamin C tablets, put them in a sock and then weight down that sock against the stained surface for at least 3-4 minutes and 10 minutes won't hurt. If the stain lessens or disappears, then it is calcium.

I suggest trying those two tests to identify the stains and, if we can clearly identify it, we can get started on a treatment.
 
well unfortunately neither the chlorine puck nor the vitamin c made any significant change. @flyweed I used the pool calculator and based on my cya level 29 was the actual suggested level for mustard algae but I didn't have enough bleach on hand to get past 24. Unless I've been misreading the pool calculator.
 
The chlorine level is irrelevant to your stain problem and I knew why you raised it there....your calculator work is fine.

Okay, there are essentially two types of stains on pool surfaces....organic and inorganic. An organic stain will lift, sometimes completely, in the presence of high chlorine levels (the puck). An inorganic stain in a pool is usually calcium but can be iron (metals) the Ascorbic acid from the vitamin C lowers the pH in the vicinity of the stain and the stains returns to solution in the water.....it goes away.

Since you had no reaction, I am at a loss and cannot tell you what to try next.....I simply don't know. :cry:
 

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if you come up with any thoughts please let me know. We do have well water but it was filled 4 years ago and subsequent refills have been put through the water softener. I have no chlorine left in the pool from the shock treatment 2 days ago. How much chlorine would you suggest I put back in it tonight?
 
yep...if you lost any FC...add more chlorine to keep your shock level up. Don't wait two days before you test and add more if need be...the quicker you stay on top of it, the sooner your problems will be solved. Good luck and keep us posted.

It must have been a bad Fall/Winter all over...as I pretty much had the same issue as you. For 3 years I've always closed and then reopened my pool to clear, blue water..NOT this year! took the cover off two days ago, and it was a green, ugly swamp! I topped the pool water up, added some sequesterant (as I have well water, with metal in it) and then started shocking with bleach. I am also taking my CYA back up to 30 currently, as that was at 0 as well.
 
I'm trying to figure out if I need to keep shocking until those stains are gone. It looks like dirt but will not sweep away, those markings are also all over the shallow end bottom of the pool. I can hold a high chlorine level over night but nothing is making the stains go away. The only thing that is abnormal are the 'dirt' looking marks. Don't know what to try next, keep it high, or let it go to an acceptable swim level and let the kids at it. If I shock do I shock to mustard algae level or just normal level? It doesn't look like mustard algae. I did put some phosphree in last night because the phosphates tested at 300. Anyone have any thoughts? I appreciate all the feedback so far, you guys are great.
 
How much chlorine would you suggest I put back in it tonight?
What is your CYA level? refer to the FC/CYA chart in pool shool.

I assume you solved this problem about how much chlorine but you don't say.

I'm trying to figure out if I need to keep shocking until those stains are gone.
Does that mean you are currently shocking? Shocking the pool will help if it's an organic stain but will hurt if it is a metal stain.

Don't get sidetracked with phosphates (irrelevant)
 
I have been shocking for a week, up until last night. When I just put enough chlorine in to boost it up to 5ppm which held over night and just now has fallen to 3ppm at noon. The water is clear, no cc's register, just the stains now. That is my dilema, do I go back to shocking for the stains, or do I try something different.

also, the pool store says my cya is 60, but I tested it before they did and again just now and I get a reading of less than 30. I have not turned the automatic chlorinator on as of yet.
 
Since you have been in the shock process for a week and your water is clear and you have experienced very little chlorine loss AND because you have stopped shocking anyway, I guess you may as well leave the FC where it is.

To complete the Shock process, you should perform the OCLT tonight and, upon passing that, be confidant there is no need to shock.

Since the stains did not respond to the shock level for a week, I see no reason to think they would respond now.

Trust your own testing on the CYA test. Why haven't you turned on the chlorinator (or is it an SWG?)
 

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