is this black algae?

[eddie1129]

[attachment=2:4eel1c0y]pool1.jpg[/attachment:4eel1c0y][attachment=1:4eel1c0y]pool2.jpg[/attachment:4eel1c0y]
this is my first pool. pool is gunite and wasn't open for 2 years. I started on saturday first using shock and then bleach and a bottle of natural chemistry first aid. I skipped mon and tues because of rain. I'm using a wire brush and it seems to be working a little. is this stained and would have to be acid washed? are there any tricks I can try to get the bottom of pool clean? or is this just a long process of shock nad scrub? 2 of the pictures are the stairs so you can see stain other picture is worse part of pool. will post more pictures if that is helpful. my fc this morning was 4 my ch is low
the pf is 7.8.any help would be appreciated

 

[Richard320]

No, it just looks like Calcium Scale. I'm sort of an expert on that, since my pool had a nice even coating of it.

Black algae will look like polka dots, very dark green or black.

Try pushing your pH down to 7.2. That helps dissolve it back into solution. It will still need brushing with a wire brush. For a year or more. If you're in a hurry, then a drain and an acid wash or sandblasting.

 

[Melt In The Sun]

All I can see is the shadow of a guy holding a camera

 

[eddie1129]

thanks. l gonna keep scrubbing and if i have to will try acid as last resort. why does shocking the pool seem to be working? it seems to get a little bit of the stain off each time I did it.

 

[duraleigh]

It may be that there is some organic stuff mixed in with the scale and the chlorine is removing the organic stuff. It is also possible it is completely organic (although I agree with Richard, it sure looks like scale)

Test a spot by holding a tri-chlor puck on it for a couple of minutes. If it is gone completely, you can simply elevate your chlorine to shock level and keep it there until the stain is gone.

For that matter, you can do that anyway and see how much improvement you get.

If so, you need to read the article in Pool School, "How to Shock your Pool".....it doesn't sound like you are doing it correctly.

 

[eddie1129]

if i do a no drain acid wash. is it ok to let the water/acid run thru my heater. I've read so many post on this site, I'm confusing myself. I thought I read one that said it would ruin heater, but i don't see a choice in the way my filter is set up, the water runs thru heater if it is off or on.

 

[duraleigh]

You will need to bypass your heater. Low pH is a no-no for heaters.

 

[2Old4This]

All I can see is the shadow of a guy holding a camera

If I squint one eye I can see Elvis

 

[eddie1129]

ph is down to 7.2 and the scrubbing seems to be working. my cH is at 200, I would assume this is good because I want the calcium to come off the pool floor. but should I raise it to suggested levels from the pool caculator

 

[Richard320]

ph is down to 7.2 and the scrubbing seems to be working. my cH is at 200, I would assume this is good because I want the calcium to come off the pool floor. but should I raise it to suggested levels from the pool caculator

No, don't add any. Keep the pH at 7.2 and it will lift it off the floor, slooooooooowly.