Newbie needs help from the experts. Is this crack an issue? What's in these drains?

[blinstedt]

Hi. I've been asked to help maintain the pool in our condo community. It was drained and winterized for the winter. It's an 18K gallon inground fiberglass. We're getting ready to paint it, and another guy pumped it out completely. He said that although it hasn't rained, water comes out of the plug in the bottom drain. He referred to it as "ground water". This scared me, so I went down to take a look at these drains. I assume that he is referring the one with the PVC plug. Is this the plug that is removed to allow flow to the filter? If so, I suppose it makes sense that water could come out of it from other water in the pipes and system. Does that sound correct? The other bottom drain appears to have a cast pipe in it. What is that pipe for?

There is also some cracks starting (see pic). Do you think that the fiberglass is compromised and needs repair? Or is this just cracks in the paint? The dark stain around the crack disturbed me, and I thought it might be dirt and that the pool might be cracked all the way through. Your thoughts?

Thanks for any feedback!

 

[YippeeSkippy]

My understanding is that fiberglass pools should never be drained. They're so lightweight that the ground water pressure can cause them to pop upwards easily.

My pool has a small dry well point dug next to the pool, covered by a skimmer box lid. This is so I can monitor and possibly drain any ground water that gets under the pool.

I think you need a professional to assess the pool for damage both from the crack and being drained all this time.

 

[JoyfulNoise]

That is most likely a hydrostatic valve and it should have been opened during the draining. It allows ground water from under and around the pool to flow up into the pool to balance the pressure. Not relieving the hydrostatic pressure from under the pool can cause it to pop out of the ground.

 

[blinstedt]

To clarify, the pool hasn't been drained all winter. It was drained to just below the skimmers. We drained the rest of it so we could paint it. It has been without water for about 6 weeks now.