Water left behind when drained?

[Zep]

I know this has been discussed before, but can anyone estimate how much water is left in your "spa guts" when you drain your tub? I realize it will vary with tub size/maker, but ballpark how much water gets left behind in the pipes, motors, ect....?

1 gallon?
2 gallons?
5 gallons?
10 gallons?

[Pathfinder]

In your tub Zep approx 10 gals would be about right.  It varies between tubs, doing winterizing on different models I've seen as little 2 gals & as much as approx 20.

[Zep]

Thanks Pathfinder......I was just discussing with my brother this topic.

He actually drains his tub basically after every use, because he only uses it when he is at his Colorado home like 6-8 times a year. It's kind of surprising that he has never had a pipe break since that much water is left in his tub guts when he leaves it empty for months at a time through the winter.

I am a big fan of draining more than less, but I realize alot of water is left behind.
My brother is no expert, but he says he fills his half way back up, then drains it again when he dumps his water, so that it lessens the amount of old water left behind? Does that theory have any merit?

Also is there any way when you drain a tub to easily drain it 100% where there is almost no water left in the guts so you truely get 99.9% real fresh new water after a drain and fill?

[Pathfinder]

For A Cal you can use a shop vac with the blow feature & put it down your filter canisters for a minute then unscrew your diverters and blow them out. Thats about the quickest way to get most of your water out of the piping.

[Zep]

Ok Pathfinder....Thanks!

[Brewman]

I put a shop vac on my spa jets once after I drained it.  I don't know exactly how much water I sucked out, but it was several gallons.  More than I'd have guessed.
That was for an 2003 Optima.
 I also have about 10 gallons, give or take, left in the footwell after that drain stops.

I usually don't worry too much about the residual water- I figure leaving in a few gallons or so of old water in a 500 gallon spa isn't doing anything bad- unless that water is contaminated due to lack of proper care or something.  If I use a flush product then I'd try and get as much out as possible.

[Zep]

Thanks Brewski......

I wish someone made a "Rolls Royce" hot tub where all this crap was automated!

[Pathfinder]

so far the best system ive seen for getting most of the water out is Hydropool where you can use your pump to drain the tub.  Bullfrog came out with a speed drain system that attached to the connection behind the seat and you could drain that way but I never saw it in use to say it works.

[Steve]

Hydropool's system is certainly amazing.

The key is not to get every ounce out but instead make sure that there are no lines full of water. Our concern is freezing and expanding lines that will burst but a bit of water will not hurt.

It seems the key points have been covered already in that regard.

A shop vac in the filter, the return and suction lines at the pak and at each jet is the trick... Suck or blow....whatever tickles your fancy!

[Brewman]

Thanks Brewski......

I wish someone made a "Rolls Royce" hot tub where all this crap was automated!

Would be nice.  My Sundance manual says in an emergency- to prevent freezing if you have to drain the spa in winter to turn on the power to the drained spa for a couple seconds to allow the pumps to blow the water into the spa.  Apparently doing this for only a couple seconds will blow most of the water out of the plumbing but not burn down the heater.  That's as close as my spa has to automation.

[Bluewater]

I too use a wet vac on all jet and in the filter cavity. I end up getting about 5 more gallons of water out.