Close without covering -- pros? cons? warnings?

[singerteacher]

I'm seriously considering closing our in-ground vinyl pool without covering it, because: we don't have the funds to buy a cover pump and we get lots of rain/snow; I'm fanatical enough to clean the water with a net until it freezes; and I'm not too worried about our far-north sun fading the pool liner, which is the only side effect I can find on TFP. But I'm wondering:

1) Are there any other possible problems with closing without covering? We did get a crack in the liner near the top of the pool last winter, which we think came from a tennis ball mis-thrown for the dog. Perhaps the liner gets more brittle and we should use extra care?

2) I'm planning to clean the water of leaves and whatever is floating with a net, but is there anything else I can do between the close and freeze-up, like stir in some bleach?

3) Before the pool store comes out to do the closing (it's our first year), I plan to have a very clean pool with FC around 10ppm. Should I also add a metal sequesterant, since we have some small brown spots on the white stairs? Or leave it until spring? Is it important that I have perfectly balanced water, or is a little imbalance okay?

4) Is there anything that the pool store can skip (e.g. putting on the cover, chemicals) that will save me money on this closing?

Thanks in advance for all your great advice!

 

[JasonLion]

Closing without covering is best done when the water is well below 60 degrees, ideally around 50. If you close too early you will have algae problems. Likewise, you need to open fairly early in the spring, before the water warms much above 50. Other than that, the only disadvantage is that there is somewhat more debris to clean out in the spring and a slightly higher chance of getting algae.

Plastic is more brittle when it is cold. It is fairly unusual the have cracking, it must have been hit fairly hard.

The metal sequestrant sounds like a good idea. Some polyquat, algaecide, is probably also a good idea. Other than those two, don' add any of the usual winterizing chemicals.

You generally want your numbers to be very good right before closing. Some of them matter more than others. If you post your current numbers we can make some more detailed suggestions.

 

[singerteacher]

My recollection with the cracked liner was that there was a gap between the vinyl and whatever is behind it. It seems that maybe there was an air pocket there, which might make it more prone to cracking when hit. I don't think it was hit excessively hard, so I have to wonder: is it normal for there to be air pockets behind the vinyl?

The pool store is going to add algaecide, but I'm not sure whether it's polyquat or not. They wanted to add Di-chlor, but since my stabilizer level was on the high side, I've asked them not to do that.

Will post numbers soon ...

 

[singerteacher]

Here are the numbers:

Temp: 56
FC: 9.4 (shocked a few days ago)
CC: 0.2
pH: 8.0
TA: 120
CH: 270
CYA: 52
Sat: 0.4

My pH is high possibly because of the high FC, but also because I was using a leaf catching contraption that fit into my return and created a venturi effect ... thus aerating my water like crazy. I'm planning to add 2 quarts of muriatic acid this weekend, along with the metal sequesterant. I'm shooting for FC around 10ppm for the closing. Is there anything else I should do?

 

[JasonLion]

Your PH is a bit high, which you should take care of before closing. Other then that you should be fine.