How much Antifreeze?

[brian11]

I have an I/G vinyl 25000 gal pool. How much Antifreeze is required in the return/drain lines? New Jersey climate.

[KirstenHW]

I asked the same question on 9/7 and no one replied to me either . . . I bought 6 gallons at Lowe's on Sat. Not sure I'll need it all. I was figuring a gallon per outlet/inlet. (2 skimmers, 2 returns, 1 wall vac line, 1 main drain). I am sure part of it depends on the length & depth of the lines.

Anyone out there have any comments?

[doggie]

We have a 25000 gallon IG, and we used a total of 5 gallons.

[KirstenHW]

Thanks, Doggie. Was that roughly 1 gallon per inlet/outlet?

[doggie]

2 gallons down the chlorine feeder, which goes to each line, 1 gallon in the skimmer, and 2 gallons in the pump filter basket. My husband says that's most likely more than needed, but better safe than sorry.

[waste]

Sorry if I missed the other ?. As a practical matter, if the pipes are fully evacuated of water, no antifreeze is required. In the same line of thought - if the pipes are not fully evacuated, but run below the frost line, no antifreeze is required. In the real world, it's a good idea to add antifreeze to lines when possible (water clings to pipe surfaces and will eventually find it's lowest level, so having the AF in there can prevent some co$tly problems). How deep a freeze you are likely to encounter depends upon your latitude (mostly), on the bottle it should say the freeze/ burst protection based on % AF to water. So guestimate how much water may be left in the line and add enough AF to compensate for the 'worst case scenario' (Ma Nature provides a record breaking freeze).
With so many people in so many climates here, that's about the best I can do - but keep in mind, the better (more thoroughly) you blow out the lines, the better chance they have of surviving the winter 'in tact'.

[KirstenHW]

So if the freeze protection is based on % AF to H2O, say there's a quart of H2O in the line plus a gallon of AF. And it gets cold - 32 degrees or lower, and the line is 2 feet down - is the AF useless then? Thx

[waste]

So if the freeze protection is based on % AF to H2O, say there's a quart of H2O in the line plus a gallon of AF. And it gets cold - 32 degrees or lower, and the line is 2 feet down - is the AF useless then? Thx

Kirsten, for exaple purposes only I'll make up some numbers (I don't have a bottle in front of me so the numbers are 'rough' and for illistrative purposes only). Say that 100% propoline glycol will not freeze until the temp reaches -30 deg. If it's diluted to 75% with water, the freeze temp rises to ~ -20 deg. , and at 50% dilution the protection is ~ -8 deg. The drop off in protection is probably more linear than this, but it serves as an example. The higher the % of AF to h2o, the better it protects.
At 32 deg water freezes, with some AF in it, the water will not freeze at 32, but how much lower the freeze point is, is dependent upon the % of AF to h2o. At 2' underground, the h2o filled pipe won't freeze until the ground temp surrounding the h2o filled pipe reaches ~32 deg ( it's actually higher because of the pipe that is 'air filled' runs through already frozen ground). As AF is cheep, when compared to the cost of digging up and replacing an ice busted line, I recommend some - how much varies with your local winter conditions and whether the pipes were run deep enough.
(I'm not real happy with this answer, but it's the best I can do for right now )