Warning - this is a long post. I've included a lot of history and detail because at this point I'm not sure what might be relevant to the issues that we are having. There are several pictures of the issues discussed at the bottom of the post.
This is my first post (EDIT: it turns out I posted in 2015 about our old above ground pool so this is my second post) but I've been reading the forum for a long time and I am thankful for the wisdom shared here. Hopefully someone can provide more insight into our problems.
First let me tell you about the pool - 35,000 gallon gunite in ground pool in East Texas. 20'x40 main pool area with a 10'x12' sundeck and 10'x10' hot tub with a waterfall into the pool.
Current water chemistry info below:
PH - 7.3
TA - 100
CH - 350
CYA - 50
FC - 6.0
Water Temp - 82 F
We just built this pool last year. It was completed in September. Within a week, the pool settled and a crack formed across the entire pool. The crack was confirmed as being all the way through the gunite with dye as the pool was losing water. A second partial crack was identified down a wall and a couple of feet across the bottom during the repair work.
Pool builder came back and did a full repair. They took a jack hammer to the gunite along all of the cracks then reshot those areas. They also did a full chip out and replaster of the entire pool, not just the cracked areas.
The replaster was completed on the afternoon of December 8th and we immediately began refilling the pool. The pool was full by the end of the day on December 9th.
Before Christmas, the pool plaster started showing these brownish stains that are an ongoing problem. The pool builder identified them as scaling but I'm not sure I agree due to the color and everything that has happened since. The stains were more of a brownish color as opposed to typical gray colored scaling.
These spots appeared on the plaster over the cracks that were repaired - in one section the stains literally had a straight line edge that followed the gunite that was removed and reshot. They also appeared all over the deep end where dirty water from loose gunite sat during the repair process. There were a few other spots on the wall around side intakes (for our second water feature pump) and one spot on the sundeck which I cannot tie to any repairs to the gunite.
The builder came back on April 11th, after the weather warmed up, and did a hot start on the pool. The stains disappeared within a day though we brushed it with a metal brush for 2 days before returning the pool TA and PH to normal levels.
By April 24th, the stains started to reappear in a few spots. By May 10th they were back in full force in the same areas of the gunite repair and all over the deep end of the pool as well as that same one spot on the sundeck.
Last week, on May 17th, the builder and plaster guy came in to attempt to buff out the stains thinking the scaling just was not removed with the hot start. They stopped after a few hours because it was too difficult to hit all the spots. The buffing did remove the stains. The plaster guy has ruled out hydration issues because there is no coloring under the stains after they buffed them out.
By May 20th, several of the spots that they did buff out started to reappear in the pool.
The current plan is to test for metal in the water. If that is negative, then they intend to drain and acid wash the plaster.
I've never had an in ground pool but this seems to be a little over the top. I am being told that I have to keep my water PH levels in a very narrow range - between 7.2 to 7.4 at all times or it will cause scaling within 48 hours. I'm sending photos to the builder every day to verify those levels. I've never heard of a pool that finicky. How would we ever go out of town for more than a day?
I'm also being told that we have to keep our CSI between -.1 and +.1 or scaling will form within 48 hours. That seems like an extremely narrow window. Everything I find online suggests CSI below +.5 will avoid scaling issues and even if it gets over +.5 scaling is not instantaneous.
I'm skeptical because new spots are appearing even if we keep the PH between 7.2 and 7.4. We are adding 1/2 gallon of acid every day to keep the pool in this range. We have 3 deck jets and 2 fountains but we do not run them at all to avoid adding to the PH. I've slowed the pool pump down as much as I feel comfortable (45GPM) to slow down the water fall so it just dribbles into the pool. We are running the pump 15 hours per day. The current 1/2 gallon per day acid usage is after these adjustments.
I'm using 2 different test kits to verify the chemistry measurements. We are also regularly adding baking soda to keep the TA up due to the high acid usage. Our TA was down in the 40-50 range when we ran a higher PH level (7.6-7.8) but I raised it to offset the lower PH our builder wants us to keep it at. The stains formed with the TA at 50 and PH at 7.8 just the same as the PH at 7.4 and TA at 100.
I brush and vacuum the pool every Sunday in addition to running the automated vaccuum for 3 hours each day.
We are on a large public water system. It has high PH out of the tap (8.0+) and high TA out of the tap (300+). That being said, we know several other people with gunite/plaster pools on this water system and none of them have these problems or come close to the acid usage that we have.
Another thing that I've noticed is that our CH levels have risen from 300 to 350 over the last 3 weeks. The 300 measurement was consistent for 2 weeks after the stains reappeared after the hot start. They rose to 330 for 2 weeks then 350 as of yesterday. I have done nothing to intentionally raise those levels.
I am using tablets for chlorine. I started with bleach but our acid usage made the costs of doing bleach and acid untenable.
One other potentially relevant note - the hot tub plaster was not redone when the repairs were done on the main pool as it was not damaged. We have not had a single stain appear in the hot tub. The same company did the first plaster job and the replaster.
I'm attaching a few photos of the repair work as well as the stains.
I would appreciate any input or suggestions on what the problem is, and even better, how to solve it. We are trying to be patient and let the builder trouble shoot the issue but I'm not sure we are making any progress at this point. Any thoughts or suggestions are appreciated.
Thank you.
This is my first post (EDIT: it turns out I posted in 2015 about our old above ground pool so this is my second post) but I've been reading the forum for a long time and I am thankful for the wisdom shared here. Hopefully someone can provide more insight into our problems.
First let me tell you about the pool - 35,000 gallon gunite in ground pool in East Texas. 20'x40 main pool area with a 10'x12' sundeck and 10'x10' hot tub with a waterfall into the pool.
Current water chemistry info below:
PH - 7.3
TA - 100
CH - 350
CYA - 50
FC - 6.0
Water Temp - 82 F
We just built this pool last year. It was completed in September. Within a week, the pool settled and a crack formed across the entire pool. The crack was confirmed as being all the way through the gunite with dye as the pool was losing water. A second partial crack was identified down a wall and a couple of feet across the bottom during the repair work.
Pool builder came back and did a full repair. They took a jack hammer to the gunite along all of the cracks then reshot those areas. They also did a full chip out and replaster of the entire pool, not just the cracked areas.
The replaster was completed on the afternoon of December 8th and we immediately began refilling the pool. The pool was full by the end of the day on December 9th.
Before Christmas, the pool plaster started showing these brownish stains that are an ongoing problem. The pool builder identified them as scaling but I'm not sure I agree due to the color and everything that has happened since. The stains were more of a brownish color as opposed to typical gray colored scaling.
These spots appeared on the plaster over the cracks that were repaired - in one section the stains literally had a straight line edge that followed the gunite that was removed and reshot. They also appeared all over the deep end where dirty water from loose gunite sat during the repair process. There were a few other spots on the wall around side intakes (for our second water feature pump) and one spot on the sundeck which I cannot tie to any repairs to the gunite.
The builder came back on April 11th, after the weather warmed up, and did a hot start on the pool. The stains disappeared within a day though we brushed it with a metal brush for 2 days before returning the pool TA and PH to normal levels.
By April 24th, the stains started to reappear in a few spots. By May 10th they were back in full force in the same areas of the gunite repair and all over the deep end of the pool as well as that same one spot on the sundeck.
Last week, on May 17th, the builder and plaster guy came in to attempt to buff out the stains thinking the scaling just was not removed with the hot start. They stopped after a few hours because it was too difficult to hit all the spots. The buffing did remove the stains. The plaster guy has ruled out hydration issues because there is no coloring under the stains after they buffed them out.
By May 20th, several of the spots that they did buff out started to reappear in the pool.
The current plan is to test for metal in the water. If that is negative, then they intend to drain and acid wash the plaster.
I've never had an in ground pool but this seems to be a little over the top. I am being told that I have to keep my water PH levels in a very narrow range - between 7.2 to 7.4 at all times or it will cause scaling within 48 hours. I'm sending photos to the builder every day to verify those levels. I've never heard of a pool that finicky. How would we ever go out of town for more than a day?
I'm also being told that we have to keep our CSI between -.1 and +.1 or scaling will form within 48 hours. That seems like an extremely narrow window. Everything I find online suggests CSI below +.5 will avoid scaling issues and even if it gets over +.5 scaling is not instantaneous.
I'm skeptical because new spots are appearing even if we keep the PH between 7.2 and 7.4. We are adding 1/2 gallon of acid every day to keep the pool in this range. We have 3 deck jets and 2 fountains but we do not run them at all to avoid adding to the PH. I've slowed the pool pump down as much as I feel comfortable (45GPM) to slow down the water fall so it just dribbles into the pool. We are running the pump 15 hours per day. The current 1/2 gallon per day acid usage is after these adjustments.
I'm using 2 different test kits to verify the chemistry measurements. We are also regularly adding baking soda to keep the TA up due to the high acid usage. Our TA was down in the 40-50 range when we ran a higher PH level (7.6-7.8) but I raised it to offset the lower PH our builder wants us to keep it at. The stains formed with the TA at 50 and PH at 7.8 just the same as the PH at 7.4 and TA at 100.
I brush and vacuum the pool every Sunday in addition to running the automated vaccuum for 3 hours each day.
We are on a large public water system. It has high PH out of the tap (8.0+) and high TA out of the tap (300+). That being said, we know several other people with gunite/plaster pools on this water system and none of them have these problems or come close to the acid usage that we have.
Another thing that I've noticed is that our CH levels have risen from 300 to 350 over the last 3 weeks. The 300 measurement was consistent for 2 weeks after the stains reappeared after the hot start. They rose to 330 for 2 weeks then 350 as of yesterday. I have done nothing to intentionally raise those levels.
I am using tablets for chlorine. I started with bleach but our acid usage made the costs of doing bleach and acid untenable.
One other potentially relevant note - the hot tub plaster was not redone when the repairs were done on the main pool as it was not damaged. We have not had a single stain appear in the hot tub. The same company did the first plaster job and the replaster.
I'm attaching a few photos of the repair work as well as the stains.
I would appreciate any input or suggestions on what the problem is, and even better, how to solve it. We are trying to be patient and let the builder trouble shoot the issue but I'm not sure we are making any progress at this point. Any thoughts or suggestions are appreciated.
Thank you.
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