Weigh sand wet or dry?

[Smykowski]

Does it make a difference? I emptied out my sand filter today looking for a possible broken lateral. Turns out, they just weren't pushed all the way down, so the sand (and dust and dirt and stuff I thought was mustard algae) was getting spit back into the pool.

This was likely due to the former owner not reinstalling the lateral assembly correctly after changing the sand a few years ago. So, in order to make sure everything is put together correctly, I'm going to weigh the sand that I've got to make sure that the correct amount is in the filter. I've got a HaywardS180T and there's no fill line on the inside of the barrel, it's just a matter of putting the proper weight in there.

How much weight in water can the sand hold? Do I have to weigh it dry, or is the difference small enough that it doesn't matter?

 

[Bama Rambler]

Sand will hold a lot of water, so I'd weigh it dry. A cuft of sand can hold about 26 lbs of water. I wouldn't go to the trouble of completely drying it but I'd let it sit in the sun a day or two.

A S180T filter holds about 1½ cuft of sand.

 

[linen]

Most 5 gallon buckets actually hold about 5.75 gallons, which would be ~0.75 cu. ft. You can test this using a gallon bleach bottle to check yours. Since the water does not increase the volume of the sand, you would need two full 5 gallon buckets (assuming 5.75 to top) of wet sand to have the right amount.

 

[Smykowski]

Great info guys, thanks. Ended up being just over two 5-gallon buckets, and given that some was wet and some was dry, I think the average brings it close enough.

Dave, where did you find the ~1.5 cubic ft for the S180T? I was all over that manual and couldn't find anything.

 

[Bama Rambler]

I have my sources.

Really the S180T holds 150 lbs of pool sand and dry pool sand weighs ~100 lbs per cuft, so the filter holds about 1.5 cuft. And I was told there'd be no math!