Leak in fiberglass pool - please help

[misteur G]

Hello,

Last week I had to refill my pool twice in three days. Even though we had some 90 degrees temperature, I though that was odd. I had to repair a leak from the skimmer two years ago, so I thought I needed to fix the same area again. I turn off the pump, and waited a few days to see the evolution. After 4 days , the water went down around 3 inches and is down below the Skimmer. So it seems to leak from somewhere else.
I have a few question, may be somebody can help with some advice.
- by turning off the pump, does it remove any possibility that the leak could be in one of the pipe?
- what other area could be subject to leak in a fiberglass pool?
- how low can the water go before it become dangerous for the integrity of the pool? I heard fiberglass can not be emptied.

Thank you

 

[mknauss]

Turning off the pump does not remove any possibility could be from a pipe. You would need to plug the returns, suction lines, etc to do that.
Any penetrations through the fiberglass could leak. So returns, main drain, skimmer, etc.
In your area, how close are you to the bay? Do you have a shallow water table? It is not good to drain a fiberglass pool, especially if your soils are not very stable.

Have you done a bucket test? Realize that evaporation is very high right now. Warm pool water and cool morning air temperatures.

 

[misteur G]

I am pretty sure it is not be evaporation, it has been way cooler in the past few week and i usually put water only twice a month during the summer months.

I am in land, so I am not sure about the water table. My goals is to not empty teh pool

 

[ajw22]

I am pretty sure it is not be evaporation, it has been way cooler in the past few week .

Cooler nights with warm days and pool water is when evaporation increases.

Evaporation of Pool Water - Further Reading

www.troublefreepool.com

 

[misteur G]

ok good to know. Thank you .the past 3 days haven't really be super warm. (mid70's). I will try the bucket test.

Cooler nights with warm days and pool water is when evaporation increases.

Evaporation of Pool Water - Further Reading

www.troublefreepool.com

 

[misteur G]

ok good to know. Thank you .the past 3 days haven't really be super warm. (mid70's). I will try the bucket test.

so 48 hours later :
the pool level is down 0.7 inch ( i have a cover blanket 16mil on the pool)
the bucket level is down 0.2 inch

What are you thoughts on these results.

 

[mknauss]

Hard to tell. You should not have the solar cover on the pool during this.

 

[misteur G]

Hard to tell. You should not have the solar cover on the pool during this.

The decrease level in the pool is already 3x more than the bucket, so I woudl think it would be even more without the blanket

 

[mknauss]

Probably true. But just another variable.

If you feel you have a leak, start searching. First place to look with a fiberglass pool is the skimmer flange, skimmer itself, etc.

 

[misteur G]

Probably true. But just another variable.

If you feel you have a leak, start searching. First place to look with a fiberglass pool is the skimmer flange, skimmer itself, etc.

THat is the location I look at first, because I already repaired it two years ago, but now the water level is below the skimmer and the water is still going down.

 

[mknauss]

Then the next places are all penetrations of the shell. Or the lines. You can plug the returns and see if it stops.

 

[misteur G]

72 hours after the last measurement I have. it has been hot the past two days 85 deg.

the pool level is down 0.78 inch ( i have a cover blanket 16mil on the pool) for a total of 1.58 in. in 5 days.
the bucket level is down 0.3 inch for a total of 0.5in. in 5 days

I am not sure where to start with plugging the return. ... What is teh best way to do it?

 

[mknauss]

What type of returns do you have?

You can get expandable rubber plugs.

 

[misteur G]

I have redone the bucket test and remove my pool cover, and it seems like the levels of bucket and pool have lowered at the same rate (after 24 hours)
I am now almost 4 inch below the skimmer level. is that becoming an issue for the integrity of the pool?

 

[mknauss]

If the bucket and pool are lowering at the same rate, that is evaporation.

You stated before you did d not have a shallow water table, correct?