pool etching problem?

[mi1980]

The water looks clear and I did some pool tests. I think the pool is about 30000 gallons and it took about 15 pounds of soda ash to get the ph back to 7.2. It uses a DE filter and when I cleaned it, it was a bright blue color which I forgot to take pictures of. The following picture shows some of the debris in the filter (the filters were that blue color):



So I'm wondering if this is a really bad etching issue. Here's some pictures of the stairs that shows the differences in color.






There is plaster flaking off on the top step but on the other images that show the stairs, the pool was the blue-green color that shows around the tiles (pool04 shows a closer view of this). In pool03, that shows the other side of the shallow end which shows the pool is no longer blue-green in color but a really faded light blue.

I took a water sample to a pool store and these were the results

FAC 2
CH 240
CYA 200
TA 110
pH 7.2
Base 6
Copper 0
Iron 0
TDS 1000
Pho 300

So I'm not sure how long the levels were/are off. I also have nieces younger than 7 and I said no one should be swimming in the pool even though the water looks clear. Is this just a cosmetic issue and I should keep running the filter until the filter stops turning blue? Or should the pool be completely drained? Or do I have to tell my mom that the pool is screwed and it has to be resurfaced?

Thanks for any help

 

[Marlahoutex]

Have you read Pool School? It has a lot of information that will help you out! Plus it has charts that you'll probably want to print out as reference. There is a Chlorine/CYA Chart, Pool School - Recommended Levels and a Recommended Levels, Pool School - Chlorine / CYA Chart
These charts, along with Pool Math, will help you where you need to be. Also, make sure you get a good test kit, like the TF-100, so you don't have to rely on the Pool store.

- - - Updated - - -

Looks like I posted the links backwards, but you get the idea.

 

[gwegan]

You have more than double the level of CYA necessary. You need to drain about 3/4 of your pool to get the CYA under control. That chlorine in there is way way to low for the CYA level its like not having any.

It looks like your acid was high for a long time and that is what has caused the problem with the finish.

I would have a pool plasterer come look at it.

You could send a private message to OnBalance our resident plaster expert and see what he thinks.

 

[pooldv]

Welcome to TFP!

Copy the IMG code to the right of the pic and paste it in your post and it will look like this.

 

[onBalance]

Your pool water contains a lot of copper, which is the blue/green substance you are seeing on the filter.
The plaster is many years old, but doesn't necessarily need a new plaster finish.
As suggested above, I recommend draining the water out of the pool and re-filling with fresh tap water.
That would eliminate the high copper and CYA content.
An acid wash might remove some of the blue/green stains, but not all.

 

[mi1980]

Your pool water contains a lot of copper, which is the blue/green substance you are seeing on the filter.
The plaster is many years old, but doesn't necessarily need a new plaster finish.
As suggested above, I recommend draining the water out of the pool and re-filling with fresh tap water.
That would eliminate the high copper and CYA content.
An acid wash might remove some of the blue/green stains, but not all.

So the recommendations seem to be drain the pool and refill to fix the CYA issue. But I think I might have created some confusion about the colors by not explaining clearly. In the above images, the areas in the black circles is the color that the pool bottom is supposed to be. My mom hasn't had any work done to the pool in the last 20+ years so everyone is correct in saying the issue is caused by the pool chemistry being off. The white circled areas show where the pool has become the faded color (the pool is not supposed to be the faded color). So the area in the black circle from the debris image, that is the correct color of the pool and that is the same color from the black circled area in the pool image above it. So even though majority of the color in pool image matches the white circled areas, that is not the correct color. It's like the filter is sucking out the color of the pool which is resulting in the areas in the white circled areas.

 

[pooldv]

Are the lighter colored areas rough to the touch? Is the lighter colored area slightly raised higher than the plaster surface or lower like the plaster is gone? You're saying the blue stuff in the pic is chunks of plaster? Then it is time to replaster.

 

[onBalance]

I am still of the opinion that the blue material found in the filter is copper residue. If you believe that it is actually the plaster surface flaking off, then there might be a way to determine which it is. Gather up as much of the blue substance in a cup, and then pour diluted acid (10 to 1) on it. If the material fizzes, then you are correct. But if the substance only dissolves, then it is a copper residue. However, perhaps there is a better way. Again, pick up some of the blue material with your fingers and try to determine whether it is flaky or crusty, which would be plaster material. If the substance is oily, filmy, or gooey, then that is copper.

You also told us that it took 15 lbs. of soda ash to raise the pH to normal levels. That would indicate that the water was so acidic, that it would remove copper from any copper plumbing, and then when the pH was raised back up, the copper precipitated out. So that is why I believe the blue/green substance is copper. Also, since the pool is over 20 years old, I think you are mistaken about the original color of the plaster. Now that I think of it, another thing you can do is to take a screw driver and poke a hole into the plaster surface and check the color below the surface. Of course, that would create a small divot, so do it a place that won't show. That would probably provide the best way to know what is going on. That is all I can think of.