I've seen this occur in the past, and I've been able to kind of rub it off with my hand. However, I noticed the line Sunday when cleaning the pool and testing the water. Sunday I tried to rub it off with my hand. No luck. Last night I was not able to scrub it off with a brush. After reading suggestions from other threads, I did a small test section with muriatic acid, and I think it helped. So my first question is: what is the best method to clean this with muriatic acid (spray bottle, large sprayer, plastic brush, ratio, etc)? My pool tile is not smooth so I'm not sure pumice would help.
As for the cause... I spent some time re-reading the info on the ABC’s of Pool Water Chemistry. I think I'm missing something. We've had a lot of rain lately so my most recent water test was probably the most out whack test I've done so far. My water hardness was low. Two weeks ago it was 220 and being just outside the range, I didn't do anything. I tested it again Sunday and it was at 125. So I was able to pick up 16 lbs of Pool Time Calcium Hardness Increaser from Home Depot. Pool math said to add 33 lbs, so I have some more coming in from Amazon today. My PH was 7.8, but my TA was 37. Baking soda is arriving today and will be added. I'm guessing I need to pick up some extra. If I'm adding MA to the pool to clean the tile, I may have to keep checking the TA and PH as that gets done.
Just another note, I typically use household bleach for my chlorine. However, I have used some pool tablets from leslie's lately b/c my CYA was getting low with all the rain we've had. My pool builder also left some 73% cal hypo that I used a few times recently when I am out of bleach.
I appreciate any advice on what I could be doing wrong to cause the line around the tiles. It should be noted that my water is usually crystal clear. My biggest headache with the pool is my neighbor has a couple of pine trees that drop sap in and around my pool. I only mention the pine sap b/c I haven't seen anything saying that would affect my pool chemistry either way. As always... thanks to everyone for the help.
As for the cause... I spent some time re-reading the info on the ABC’s of Pool Water Chemistry. I think I'm missing something. We've had a lot of rain lately so my most recent water test was probably the most out whack test I've done so far. My water hardness was low. Two weeks ago it was 220 and being just outside the range, I didn't do anything. I tested it again Sunday and it was at 125. So I was able to pick up 16 lbs of Pool Time Calcium Hardness Increaser from Home Depot. Pool math said to add 33 lbs, so I have some more coming in from Amazon today. My PH was 7.8, but my TA was 37. Baking soda is arriving today and will be added. I'm guessing I need to pick up some extra. If I'm adding MA to the pool to clean the tile, I may have to keep checking the TA and PH as that gets done.
Just another note, I typically use household bleach for my chlorine. However, I have used some pool tablets from leslie's lately b/c my CYA was getting low with all the rain we've had. My pool builder also left some 73% cal hypo that I used a few times recently when I am out of bleach.
I appreciate any advice on what I could be doing wrong to cause the line around the tiles. It should be noted that my water is usually crystal clear. My biggest headache with the pool is my neighbor has a couple of pine trees that drop sap in and around my pool. I only mention the pine sap b/c I haven't seen anything saying that would affect my pool chemistry either way. As always... thanks to everyone for the help.
