On Monday, March 4, 2019 at 7:37:06 PM UTC-5, wrote:
On Mon, 4 Mar 2019 13:24:07 -0800 (PST), trader_4
wrote:

On Monday, March 4, 2019 at 4:07:24 PM UTC-5, wrote:
On Mon, 04 Mar 2019 04:44:01 GMT, Shay
m wrote:

replying to Danny D., Shay wrote:
Just for info. If you touch a main drain or swim around it, you wont feel
the water flowing nor suction. Reason being is because the covers are
anti-vortex. But aside from that, main drains are not like a bathtub where it
sucks in water forcefully. They pull in particals from the water, not just
water. And if you have a hot tub/Spa, you might see leaves or other debris in
the spa getting sucked toward the drains. This is because the drains In a spa
are stronger and the jets in the spa circulate the debris. And a main drain
isnt actually a drain, its a housing pipe, suction outlet that goes back
to the pump. Just wanted to put that out there.

The best (safest) way to tell is with a stick of PVC pipe. Pour some
water in the top with a little food color in it with the pipe a foot
or 2 from the drain. If the drain is working the color will be sucked
in. If it just pools around, the drain is not working.

I used food dye to figure out the approximate location of a leak in a
skimmer line one time. The symptom was that small stones were showing
up in the filter basket. Then I observed that dirty, mud color water
showed up at the filter some seconds after the pump started. So, I
put some food coloring in the skimmer, turned on the pump and counted
the seconds for it to reach the filter. I also timed how long it
took for the muddy water to show up. Then I used the ratio of the
two times to figure that the break must be about at about 20% of the
run length, closer to the pump. Maybe I didn't need to do that, because
the next thing I came up with was to pressurize the line with the air
compressor. Doing that, I heard hissing and bubbling and there was air
coming out of the ground, right about at the predicted distance.
Fortunately the spot was just short of the stamped concrete deck.
Upon investigation, it looked like it was compromised when they backfilled
it some years earlier. It was that flex PVC and it was crushed and broken.
Had it been under the huge deck, that would have been a disaster.

I still have a little patch of grass next to my pool, right where the
skimmer is because that is where most pool leaks show up. The dog
likes a little grass there too. It is a comfortable place to take a
nap.

It's probably a good idea to make a deck out of pavers instead of stamped
concrete too. At least with regular concrete if you need to cut it, take
out a section, replace it, you can do that, though it may not match too well.
But with stamped I don't think you have a prayer. Sometimes I wonder how
many pools up here are not really winterized right, blowing out the lines,
correctly plugging them, etc. and people just get lucky because they are
deep enough and it just doesn't get cold enough most winters for them to
freeze and bust.