1. Suction side air leak. 2. High CH, low pH, low TA, added baking soda but can't get rid of precipitate.

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draco aqua

draco aqua

Bronze Supporter
Jul 2, 2019
20
Los Angeles / California
Pool Size
16752
Surface
Plaster
Chlorine
Liquid Chlorine
I was recently asked to look at a pool the forum helped me stabilize years ago.

1. The initial problem of why I was contacted was that there was a suction side air leak whenever the automatic pool vacuum (Barracuda MX-8) was connected to the skimmer. I changed the hoses and still got a leak. Then I tried hooking up 1 hose section at a time (this vacuum uses twist lock hoses). To my surprise, even with just 1 new hose 3 foot hose section fully primed with no air in it connected to the top skimmer, I would still get a large air leak in the pump basket. I would get no air leak when the top skimmer was just functioning as a normal top skimmer basket. Is the additional pressure caused by hooking up the vacuum hose causing the leak to appear?

It was time for a filter cleaning anyway, so I changed the grids and manifold (grids were well worn), changed the standpipe o-ring, changed the large filter o-ring, changed the pump basket o-ring, and tested every joint and plug by pouring running water over it with a hose. I couldn't find the air leak. Now I'm wondering if it's maybe a cracked skimmer pipe that only shows up when a vacuum hose is attached to it and there is additional load placed on the pump system?

I don't know if anyone has experienced anything similar, but any suggestions on where I might be able to trace this leak? I don't like running the pump too long in the air leak state as it will lose prime fairly quickly.

I've done a bucket test, and I don't seem to be losing any water. It just appears to be an air leak.

I resorted to just placing a basket in the top skimmer.

I was in the process of contacting a leak detection company.

2. I went to check the water balance.

The first test I got, the water was clear, but the numbers were way off.

FC 5
CC 0
pH 6.8? (It was below 7)
TA 10!
CH 1875!
CYA 30
Salt 3200
Temp 65
CSI -1.56!

When the forum helped me with this pool years ago, the CH was fairly high, but below 1000. Now it's solidly above 1000.

As far as I know, they were using liquid chlorine to chlorinate the pool. They floated pucks for 2 weeks prior to my arrival when they went on vacation.

From these results, I added about 10 pounds of baking soda with the goal of bringing total alkalinity to 50. For a 22K gallon pool I believe the calculation was for 16 total pounds of baking soda to reach TA 50. I'm glad I didn't do the full amount. I also added about 1/3 gallon of chlorine to try to bring FC to 6.

The second test 2 days later:
FC 7
CC 0
pH 7
TA 75
CH 1750!
CYA 30
Temp 67
CSI -0.18

The problem now is that I've got a cloudy pool. It's blue and I can see to the 3rd step in the shallow end but not the main drain in the deep end. It looks like baking soda hasn't dissolved or I'm getting calcium precipitating out. It appears that I overshot on the TA which makes me wonder if my pool volume calculation was off.

Any way to clear out this cloudiness?

I'm thinking this pool needs to be drained. I've struggled with this decision even years ago. I'm thinking of using an RO filter company. For a 20K gallon pool, they quoted me $1K for the job. I like the fact that most of the water will stay in the pool being that it is the hottest time of the year.

I'm not sure if this is better than just simply draining and refilling it?

3. Questions:

At this point, should I do the leak detection / repair first?

Is it even possible to do a leak detection in a partially clouded pool or should I try to wait and see if I can filter out all the precipitate?

Does anyone have experience with RO pool filtration versus draining/refilling the pool in the middle of July?

Thanks in advance!
 
draco aqua said:
I was recently asked to look at a pool the forum helped me stabilize years ago.

1. The initial problem of why I was contacted was that there was a suction side air leak whenever the automatic pool vacuum (Barracuda MX-8) was connected to the skimmer. I changed the hoses and still got a leak. Then I tried hooking up 1 hose section at a time (this vacuum uses twist lock hoses). To my surprise, even with just 1 new hose 3 foot hose section fully primed with no air in it connected to the top skimmer, I would still get a large air leak in the pump basket. I would get no air leak when the top skimmer was just functioning as a normal top skimmer basket. Is the additional pressure caused by hooking up the vacuum hose causing the leak to appear?

It was time for a filter cleaning anyway, so I changed the grids and manifold (grids were well worn), changed the standpipe o-ring, changed the large filter o-ring, changed the pump basket o-ring, and tested every joint and plug by pouring running water over it with a hose. I couldn't find the air leak. Now I'm wondering if it's maybe a cracked skimmer pipe that only shows up when a vacuum hose is attached to it and there is additional load placed on the pump system?

I don't know if anyone has experienced anything similar, but any suggestions on where I might be able to trace this leak? I don't like running the pump too long in the air leak state as it will lose prime fairly quickly.

I've done a bucket test, and I don't seem to be losing any water. It just appears to be an air leak.

I resorted to just placing a basket in the top skimmer.

I was in the process of contacting a leak detection company.

2. I went to check the water balance.

The first test I got, the water was clear, but the numbers were way off.

FC 5
CC 0
pH 6.8? (It was below 7)
TA 10!
CH 1875!
CYA 30
Salt 3200
Temp 65
CSI -1.56!

When the forum helped me with this pool years ago, the CH was fairly high, but below 1000. Now it's solidly above 1000.

As far as I know, they were using liquid chlorine to chlorinate the pool. They floated pucks for 2 weeks prior to my arrival when they went on vacation.

From these results, I added about 10 pounds of baking soda with the goal of bringing total alkalinity to 50. For a 22K gallon pool I believe the calculation was for 16 total pounds of baking soda to reach TA 50. I'm glad I didn't do the full amount. I also added about 1/3 gallon of chlorine to try to bring FC to 6.

The second test 2 days later:
FC 7
CC 0
pH 7
TA 75
CH 1750!
CYA 30
Temp 67
CSI -0.18

The problem now is that I've got a cloudy pool. It's blue and I can see to the 3rd step in the shallow end but not the main drain in the deep end. It looks like baking soda hasn't dissolved or I'm getting calcium precipitating out. It appears that I overshot on the TA which makes me wonder if my pool volume calculation was off.

Any way to clear out this cloudiness?

I'm thinking this pool needs to be drained. I've struggled with this decision even years ago. I'm thinking of using an RO filter company. For a 20K gallon pool, they quoted me $1K for the job. I like the fact that most of the water will stay in the pool being that it is the hottest time of the year.

I'm not sure if this is better than just simply draining and refilling it?

3. Questions:

At this point, should I do the leak detection / repair first?

Is it even possible to do a leak detection in a partially clouded pool or should I try to wait and see if I can filter out all the precipitate?

Does anyone have experience with RO pool filtration versus draining/refilling the pool in the middle of July?

Thanks in advance!
Click to expand...
Leak detector will want the water clear before coming out. I had to send them a picture of the water the day they scheduled.

Though they could just plug the skimmer lines and pressure test them without having to scuba dive the pool itself. Maybe ask them first.

But if your CH is that high you’ll need to replace the water anyway. You can do an no drain exchange if your source water isn’t high in CH.
 
Thanks for the reply. I showed them a picture from today, hoping that it clears up more in a week. He was actually ok diving it in its current state with 4 foot visibility. The valves to both my main drain and skimmer have seized, so he said he would have to access / plug the main drain from the deep end of the pool.

These particles seem so small. Would cleaning and replenishing the DE filter even help or should I just filter at a faster speed?

Any ideas on how to clear the cloudiness? It’s mainly a white film on top of the pool.

This is about 48 hours past adding the baking soda.

IMG_8589.jpeg
 
Pool water TDS essentially is CH, CYA, and salt.

Tap water TDS is CH and salt. Essentially not much more than CH.
 
The precipitation has gotten worse to the point I’ll have to do a full drain and refill or a no drain water exchange before being able to do a leak inspection and I can't RO filter the pool in this state. What a mess!

I’d prefer doing the full drain and refill as there are a lot of calcium deposits at the bottom of the pool that I would like to be able to clean, but the temps will be above 90F so I’m not sure if this is very safe.

I'm thinking I shouldn't wait on correcting this.

If I do a no drain water exchange, would I be able to achieve very close to the same goal as a full drain and refill?

A few questions regarding the no drain water exchange I wasn’t able to find the answer to searching the forum:

  1. I would need to exchange 90% of my water. I’m assuming the success of the water exchange is dependent on the gradient between the super salty pool and the fresh water entering it. I plan on putting the pump in the deep end, and fresh water entering on the shallow side. The fill water and pool temperature are fairly close.
    1. As the exchange progresses with time, does the gradient decrease to the point where it will reach equilibrium before I can exchange all that water? Basically I don't want to waste more water than necessary.
    2. Would I plan to replace 100% of my water to achieve that goal?
  2. I have a lot of calcium precipitation that just settles to the bottom of the pool. Will this eventually dissolve into the fresh water as the exchange progresses? If not, how would I get rid of it?
  3. Just from a practical / safety standpoint how do you monitor this overnight? Are you setting alarms every 3 hours to check the progress? I think this will take about 48 hours.
  4. Is it ok to float pucks during this 48h period or is that not usually necessary?

As far as what to order, I'm thinking:
1. 1/3 HP submersible utility pump
2. Flow meters to measure the pump outflow and the fresh water intake
3. I might need a 100 ft hose to reach my cleanout. I'm hoping that doesn't significantly decrease the pump flow rate.

Am I missing anything else?

Thank you!
 
draco aqua said:
The precipitation has gotten worse to the point I’ll have to do a full drain and refill or a no drain water exchange before being able to do a leak inspection and I can't RO filter the pool in this state. What a mess!

I’d prefer doing the full drain and refill as there are a lot of calcium deposits at the bottom of the pool that I would like to be able to clean, but the temps will be above 90F so I’m not sure if this is very safe.

I'm thinking I shouldn't wait on correcting this.

If I do a no drain water exchange, would I be able to achieve very close to the same goal as a full drain and refill?

A few questions regarding the no drain water exchange I wasn’t able to find the answer to searching the forum:

  1. I would need to exchange 90% of my water. I’m assuming the success of the water exchange is dependent on the gradient between the super salty pool and the fresh water entering it. I plan on putting the pump in the deep end, and fresh water entering on the shallow side. The fill water and pool temperature are fairly close.
    1. As the exchange progresses with time, does the gradient decrease to the point where it will reach equilibrium before I can exchange all that water? Basically I don't want to waste more water than necessary.
    2. Would I plan to replace 100% of my water to achieve that goal?
  2. I have a lot of calcium precipitation that just settles to the bottom of the pool. Will this eventually dissolve into the fresh water as the exchange progresses? If not, how would I get rid of it?
  3. Just from a practical / safety standpoint how do you monitor this overnight? Are you setting alarms every 3 hours to check the progress? I think this will take about 48 hours.
  4. Is it ok to float pucks during this 48h period or is that not usually necessary?

As far as what to order, I'm thinking:
1. 1/3 HP submersible utility pump
2. Flow meters to measure the pump outflow and the fresh water intake
3. I might need a 100 ft hose to reach my cleanout. I'm hoping that doesn't significantly decrease the pump flow rate.

Am I missing anything else?

Thank you!
Click to expand...
If you do the exchanges, you want to disturb the water as little as possible (no floater). Also do the testing the tutorial recommends as the water in and out locations will depends on that somewhat. You’ll want to vacuum to waste as much junk as you can before starting as that would just contaminate your new water.
 
Using a 100' hose for the effluent will restrict your flow to likely 4 or at most 5 gpm. This will be very slow. The efficiency will drop some.

Test the pump now with the hose attached and see what flow you get. Use a 5 gallon bucket and time how long it takes to fill. No real need for flow meters.

If you need 90%, I would do 110% in reality. Should get close.

The solids should be vacuumed to your filter or to waste.
 
Yes…. I’ll be sure to post those delta T calculations here before starting!

1. About not disturbing the water - is it best to have the pool pump off for a few hours before starting the exchange to allow the heavier salts to settle at the bottom of the pool?

2. As far as vacuuming…. My pool isn’t piped to be able to vacuum to waste. And I have that unfortunate suction side air leak making even vacuuming into the filter impossible at the moment.

Is it possible to rent an external pool vacuum? I’m not sure I’ll be able to vacuum it up even with that though.

I have an Aiper SE self contained robotic vacuum that I’ve tried to place in the pool. The calcium sediment just blows away like a cloud of dust as the robot approaches it. Brushing it does the same thing. It makes the water more cloudy. Any suggestions of how to pull this out of the bottom of the pool?
 
draco aqua said:
. The calcium sediment just blows away like a cloud of dust as the robot approaches it. Brushing it does the same thing. It makes the water more cloudy. Any suggestions of how to pull this out of the bottom of the pool?
Click to expand...
This sounds like dead algae. Calcium would be very heavy and not poof away.

Just follow the process.
 

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Wow, that is truly terrifying.

I would guess that it is either copper or paint that has all come off.

Is the pool painted?

If you rub your hand on the wall, does it leave blue paint residue on your hand?

img_1558-jpeg.513829


img_1557-jpeg.513828
 
Hi James, the pool is not painted as far as I know. It should be just white plaster. The only thing blue is the tiles at the water line.

I get a fine blue precipitate on the floor, walls, and steps but it leaves no residue on my hands.

Now cleaning the DE filter - that was a different story. It looked like I smashed a Smurf! That pasty blue got everywhere.
 

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