Sciencemadness Discussion Board

sand filter help please

red13 - 8-4-2011 at 17:43

hi first post newbie sorry if i ........ etc have looked

can anyone please tell me about the use of sand filter to use as an alternative to filter paper that would otherwise block up. any tips etc thanks

m1tanker78 - 8-4-2011 at 18:32

It depends on what you plan to run through it. For general use here's what I do...

Run it through a strainer - especially if it's beach sand. Wash it religiously by putting it in a bucket along with water, swirl it with your hand, let the sand settle then decant the water. Repeat the washing step several times even after the water looks clear. Allow the sand to dry thoroughly on a tarp or better yet, on a large piece of cardboard so it can later be stored.

Optional: After the washing steps, add some muriatic acid to a slurry of 1:2 sand:water then add in a copious amount of 3% hydrogen peroxide. Stir it every minute or so for around 10 minutes. If the solution remains turbid even after the sand has settled then you may need to repeat the acid/peroxide step. Decant, wash 5 times then LIGHTLY alkalize with hydroxide or I guess baking soda would work too. Stir every minute for 5 minutes. Decant and wash 2 or 3 times. Lighly acidify the slurry (a cap full or 2 of muriatic should be plenty). Stir it vigorously for a couple of minutes then give it a few washes. Dry and store it for later use. This works best if doing ~2 gallons of sand in a 5 gallon bucket (at least that's how I did it 3 or 4 years ago). I still have clean sand put away.

Don't expect the sand to turn white or anything. Mine went from dark brown to light tan.

God, I think I've gone crosseyed! :o

Tom

blogfast25 - 9-4-2011 at 09:23

Sand filters can be an interesting proposition if you’re interested in the filtrate more than in the precipitate (which inevitably ends up mixed with the sand). I imagine many an alchemist may have resorted to sand based filters, before the advent of modern filtering media. Sand’s chemical inertia and heat resistance are also plus points.

Tanker78’s procedure for cleaning up any beach sand sounds about right to me. But there are other considerations to take into account like sand bed depth and sand support system. I’m also guessing flat bed sand filters are preferable to conical beds. Only experimentation can show which kind of sand filter is a solution for which filtering problem…

red13 - 11-4-2011 at 20:22

thanks ml tanker and blogfest you both gave me useful info. i would use mostly for a filtrate. i agree with the flat bed funnel being better. i will remember to clean off to an extream. by the way this is an owesome web site. thanks both of you for the useful tips.