Pool Stains ???

[mxdad777]

I had to drain my pool down yesterday to lower my CYA. While the water was down I took some pictures of the side wall. When the water was full, I thought it looked like a mustard algae or something similar. Now that I see it with no water, I'm not sure. My pool is 28 years old and yes, it's the original plaster. We plan on re-plastering or pebble tech within the next two years, but it's not in the budget right now. Are these blotches a stain of some sort, or is it just the plaster wearing thin? Yesterday prior to the drain, my numbers are listed below.

FC 5
TC 5
CC 0
PH 7.3
TA 200
CH 350
CYA 200
Salt 3400
Water temp 68 deg

 

[PSW]

To determine if this is a metal stain, try rubbing a vitamin c tablet on a stained area for 1-2 minutes. If the stain fades, then you are looking at a metal (copper) stain. If not, the stain is likely organic..and you should shock your pool.

 

[mxdad777]

I tried rubbing the vitamin C tablet on the stain and it didn't do anything. The stains have been there for at least 2 1/2 years (since I bought the house) and the pool is 28 years old with the original plaster. I think it might be the plaster that is deteriorating rather than an organic stain. Is there a way I could find out without shocking the pool if it really is an organic stain? I don't want to go through the trouble of shocking the pool if it's the plaster. Thoughts???

PS After my water change, my levels are as follows:
FC 3
TC 3
PH 7.6
TA 325
CH 310
CYA 75

 

[Butterfly]

You can try rubbing with a trichlor tab to test for organic staining.

If no results, go back with some crushed vitamin C (the cheap stuff) in a sock and let it sit on the stained area for a little while to test for metal staining.

 

[mxdad777]

You can try rubbing with a trichlor tab to test for organic staining.

If no results, go back with some crushed vitamin C (the cheap stuff) in a sock and let it sit on the stained area for a little while to test for metal staining.

I tried the trichlor tab today and it didn't do anything. I then tried the crushed vitamin c in a sock and left it for 5 hours, it also did nothing. I'm really starting to think that it's the age of the plaster and the plaster deteriorating. Is this what old plaster does, or am I way off base?

 

[duraleigh]

28 year old plaster?? No doubt you have got your money's worth :lol: Yes, it looks like worn plaster to me and your tests certainly would indicate that as well.