Pool sand, thoughts & a cheap source I found.

[y_not]

In hunting for pool sand, which is NOT CHEAP here. YIKES!!
I found a lovely secret, which I wondered about but had no way to verify it without time, testing & money of which I'm not equipped to do.

Calling around, finding prices from $20/100# - $16/50#, I felt this was rather overly priced and silly to pay that for sand. Yeah, I know it ain't free, but that's a RIP!
So I kept calling around, but changing my tactic from there on out and saying: "hey, the prices I'm finding are pretty high. I have got a 600lb filter I need to fill here and I'm really not inclined to pay $120-$150 for the sand, at best."
So I found a pool service in a nearby town, still on my side of the hill, that took pity on me and told me a little secret.
He said to call up Willamette Greystone and ask for #20 Quartz Sand.

He said; it's as good as, or better than even the glass based medias, it lasts a long time, it's super clean and very finely washed with great uniformity. He also stated that he has been using it for 20 years with no problems.
He then told me that it was just too much trouble for him to bother going over there to pick it up and load it into his pickup and bring it to me just to make $50. He'd rather I just go buy it and save some money that way.
Really nice of the guy!!

So I call them up, found out it's made by Unimin - 4095 #20 grade.
It's white sand @ $12/100# bag.
$12?? WOW!!
That's more like it. Only $72 ($50 savings) to fill the soon to be in my possession, monster filter.

BTW, for any of you Oregonians out there. Willamette Graystone is all over oregon with like 10 locations.
Plus I'm sure if you call around to your local distributors of quarried rock and non metallic mineral fillers, you'll find this stuff. Unimin has piles and piles of quarries all throughout North America, Canada & Mexico. So go get 'em and save yourselves some money by skipping the overpriced pool & hardware stores.

I'll definitely be picking up what I need from WG when I get my filter here. At those prices, who wouldn't!!
Plus, it sounds tried and true.


Now, for the slightly more detailed stuff and a question. ........

 

[y_not]

Looking it up online, I see it's used a lot by aquarium folks, the ones that have used it say they get absolutely no dirt or any sort of cloud out of it when they wash it or put it in the tank. It doesn't even need washing it's so clean.
I found a spec sheet on it. It says Granusil as the brand /w Unimin as the manufacturer. So I'm assuming that's just the name Unimin uses for this product, instead of their direct name.

Either way, the spec sheet shows Unimin at the bottom.
Unimin #20 - 4095 White Silica/Quartz Sand - Grading Seive Specs

What I'm confused by though, is this. The sheet shows that it's primarily 30/40 mesh. Almost 40% & 60% respectively. Looking @ Wikipedia: http://en.wikipedia.org/wiki/Mesh_(scale)
I see that's a grain MM size, under US Std. Mesh, of 0.4-0.6mm (rounded). With 1.2% @ 0.84mm & 5.1% @ 0.3mm.
So there's a tiny bit of big stuff and a tiny bit more still of pretty small stuff.

Looking at the specs of filter manufacturers and the specs of, say AquaQuartz brand pool sand. I see they all say 0.45-0.55mm. How is that possible?
Looking at the mesh grading in the Wiki article, those sizes don't even exist.
So where do they come from?

I'm thinking they're rounding them, where in fact they're using a screen close to that and not the actual screen. Since it doesn't exist.
The "Tensile Bolt Cloth" screens come closest. IE. 42/44 is closest to .45mm & 33 is closest to .55mm. *Note, 43mm isn't listed because it's simply a different size wire mesh with the same size hole. Either for more durability or more screen pass through area. IIRC it's the latter.

As per this quote from the Wiki article.

Some users replace some of those indicated above with 45, 22.4, 12.5, 11.2 and 5.6mm sieves, mostly because of historical usage of such sizes in their country or industry.

So where do these falsified numbers come from and is this "pool sand" ok?

Yeah, I know a pool guy says it is, but I want to be sure. As I don't know him nor do I know how good he is.
Case in point: I had a different pool guy that also uses this sand, tell me that it only lasts 5 years before you have to change it. You should really use glass or zeo. Not to mention he told me you should never use DE in your sand filter. It'll ruin it. Really?? HAHA!!
Boy did I kinda get into it with him on that 1st one. I was nice about it and didn't put him down or anything. That's not cool.
I told him it's impossible for it to wear down that quickly, as it's not in the ocean being tumbled around. He seems to think that inside the filter it is constantly tumbling around. I told him it's a "cake", a compacted bed of sand where the dirty water fans out over it and trickles down through it, thus trapping the dirt and organics within the 1st 1-2" of sand. He didn't seem to think so.
He was getting all hot under the collar and frustrated, so I dropped it.
I told him I wasn't arguing with him, just having a healthy debate of knowledge. But he only went so long on that.
Being closed minded really gets you a long way in life.

I didn't even begin to get into it with him on how then the filter was supposed to trap dirt if the sand was constantly tumbling around in there, wearing it down as he says. Oy'VEY!!!
Some people...

So yeah, I'd love ya'lls opinion on the matter.



Scroll on for some really gory stuff I pulled up in my research hunt.

 

[y_not]

WARNING!! This post contains really boring technical data and links to even far more boring technical books on sand based filtration regulations, theories of operation & testing.
DO NOT proceed to read this particular post unless you are a nerd, bored, or wish to begin your masters in wastewater & pool filtration technologies.
If none of that applies, then please head on down to post #4 and beyond. Thank you!
Otherwise, you may now proceed. You have been warned!


In looking at the spec sheet and using the UC formula, I'd have to guestimate, since all the data's not there for this.
That the approximate UC of this sand is: Uniformity Coefficient - 1.4%
I won't even bore you with how I figured that, but I averaged it based on the listed data of sieve retention of grains.
I'll admit, it hurt my head a bit, but that's nothing new with math.
Either way, I will be calling the manuf. to find out it's rated UC percentage.
Handbook of Filter Media, Second Edition - 2002
In there, on the page linked, you'll find a Uniformity Coefficient Explanation that made the most sense, at least to me.
That book is a good read too, some interesting findings in there on slow rate & high rate sand filters.

It is interesting to note that the book states the following, canceling out what I have referenced in the Washington State document, just after this paragraph.

"Later research demonstrated that, even when restricted to slow sand filters, the uniformity coefficient is of little relevance to the performance of the filter."

Now isn't that just simply contradictory in nature???
Makes you wonder what is right and the basis thereof.

Here: www.doh.wa.gov/Portals/1/Documents/Pubs/337-104.pdf+&hl=en&gl=us&pid=bl&srcid=ADGEESgVEp7RKXqORpe7uKJ4RAfdKmB8rxiN02EQ2hudcQvyEvUs5UXw9kvPd7UrNkucpKZToELUFdz31e1jccloaG2V3Gn_bGrB27AJKOpmB3rcHPbBfOYnN1n_-aHZ9bQ2msg4eR-n&sig=AHIEtbQCFVzUCbVT0naN7i8W3u-uYvtEMA]Sand Grain Size - Washington State Department of Health Wastewater Management Program[/url]
It states on pg., end of the 1st paragraph, that the ideal effective grain size for sand in a filter is 0.3-0.5mm. The following few paragraphs and then the details & graphical representation of grain size spacing on pg.4 are well worth a read.
Also on pg. 4 it states that a UC %?4.0 is best for filters. IE. The least ammt. of variance in grain size, as shown in the graphic. So this sand, assuming, and that's a big "IF", my guesstimate is correct, it's way down the scale and has very little variance in grain size. So this should confirm the recommendation. But really, I won't know for sure till I contact Unimin to see what they're testing shows that the UC % is.

Some stuff to chew on, or comment if you're so inclined to do so.
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