Can I drain my in ground pool for the winter?

[Fungi]

My pool is three years old. Every year when we open it the water is beyond disgusting. Mold and slime is so thick. This spring I had to drain it just to get rid of a relentless CC that would not break after almost three weeks of slam. The pool is fiberglass in ground. It has a roof made from Polycarbonate. I had no issue draining the pool June 6th, during an unusually wet spring. The other issue is the antifreeze. The amount used is the same for my 2300 gallon pool as it is for an 18000 gallon pool. I pump to waste as much of it as I can, but what's in the return lines just goes into the pool. It's not diluted as much as a larger pool. If it only takes 3 hours to fill it, why am I trying so hard to keep the water?

I included some pictures to illustrate how the pool is constructed. The soil is very sandy. It is built on a small section of flat at the edge of a long sloping hillside that droops 80 feet. I can stand at a level even with the bottom of the pool just 15 feet down from the pools edge. The concrete patio above the pool is properly drained. Very little water can make it into the pool room, and has to go through the screens. Water does run away from the pool on all sides. My point is it's pretty impossible for the water table to exist in this location.

Can I just drain it completely for the winter?

Will it harm the pool cover to have it not supported by water?

Can I be sure all water can be drained from the lines?

Alternately should I drain it as shown, about 1/4 of the water remains, and just drain it the rest of the way in the spring?

Are there any other issues I should be concerned with?

Here are the pictures. Thanks in advance for any guidance!

- - - Updated - - -

 

[S1ngram]

I also live in central Illinois. There are a few people on this forum that will tell you to open early and close late. I agree with that statement and it has worked well for me so far. I opened mid-April and I'm still not closed yet...it will be October before I can shut down completely. I use algaecide when I close as extra protection. If the water is 60 degrees, you need to be adding chlorine to the water.

I know there have been some members with troubles regarding antifreeze in the pool, so I'm sure you can find info on that topic. I can't help with your decision to drain or not. Is there any sort of warranty that could be voided if you don't have water in the pool?

 

[PAGirl]

You should never drain a fiberglass pool completely. It could lift out of the ground.

 

[Fungi]

Thanks S1ngram, I have been paying a place to close it as insurance if something went wrong. But if I drain it completely there is no chance of a pipe getting frozen.
Hey PAGirl, Yes, the pool can become buoyant if the water table rises, hence the details of the surrounding environment. I just don't think there is any way the water table can raise in this location. It is in essence an indoor pool.

 

[PAGirl]

Would the ground freezing be a concern?

 

[pabeader]

Any reason to drain it at all? With the enclosure I'm wondering if it actually freezes, even in Illinois.

 

[Texas Splash]

Fungi, the relatively small size of your pool "may" allow you to get away with a total or near-total drain - perhaps. I too have a Viking pool but don't recall any allowances in the warranty to drain based on size, but as the owner you certainly have that prerogative. If you chose not to drain, you could follow the following procedures here: Pool School - Closing an In Ground Pool should serve you quite well. I understand from your pics the pool is enclosed and somewhat protected from the elements throughout the year, but the procedures outlined in the link above are there to not only protect your pool shell and plumbing, but designed to significantly reduce the chance of getting algae and save you money from a total refill and adding new chemicals from scratch. If you've never closed your pool via the TFP closing method, I would recommend trying it at least once.

 

[4knights]

The exterior or above water portion is enclosed, the actual pool is underground and water table is linear in nature. Meaning that if the surrounding area begins accumulating water( rain, snow, underground spring, flooding for some other source) your pool is the area of least resistance.

If there's no water in it, it is very likely to heave or collapse inward. :study: if you drain it because insurance company or the pool builder- said its ok- get that in writing, witnessed and notorized.

I don't close till mid October if at all possible. I drain only enough to reach below my returns. I blow all lines out with a shop vac,(bottom drain is air locked) plug them with rubber stoppers and a gizmo in the skimmer. I add pool antifreeze in the lines( total 2-3 gallons) just in case there is some water in there. I add some algaecide (polyquat 60).

The ground freezes to 38 inches here in Kansas

 

[Fungi]

I forgot to attach the image of when I drained it first week of June. We had already gotten 7" of spring rain by then. I had no problems going to only 1 foot deep. Well I was convinced it would be ok, but am now having doubts... Oh what to do... :/

 

[tim5055]

How cold does the water get?

Is the equipment inside the structure and is it protected?

 

[Fungi]

Hi Tim, I honestly have no idea how cold the water gets. I've never opened the cover in the winter. We have had lows of -15F and a several week stretch of below 32F highs. I assumed it froze. The room only has screens. The equipment is outside. The pool cover is brown and does collect some heat in the daylight.

 

[tim5055]

Hi Tim, I honestly have no idea how cold the water gets. I've never opened the cover in the winter. We have had lows of -15F and a several week stretch of below 32F highs. I assumed it froze. The room only has screens. The equipment is outside. The pool cover is brown and does collect some heat in the daylight.

OK, if it were me I would not drain but follow the late close/early open procedure. Do not close the pool and stop pumps/chlorine until the water is below 60 degrees, 50 would be even better. Re-open next year between 50 and 60 degrees.

You will end up running the pump a little later in the season and earlier next year, but you have the best situation going. Between the roof, screens and cover very little organic matter is going to get in the pool and the cold water will slow down any algae growth.

It sounds to me like you have been closing early and opening late which = recipe for algae.