Post by Apoplast on Mar 31, 2013 17:32:39 GMT -5
Good day all - Okay, so I should say up front that this is not going to be the most exciting post compared with posts that have great pictures of plants. Still, I'm a bit of a nerd when it comes to this stuff and so I wanted to share just in case there were others out there who are too.
The silica sand I can get near me still has a shocking about of solutes associated with it, and it is contaminated with alkaline sand. Not much I can do about that, it's all locally sourced around here and our water is pretty hard. What I can do is get rid of the problem by acid washing the sand.
Acid washing is done on small glass beads for micro-nutrient studies of plants that won't grow well in hydroponic culture. It gets rid of pretty much anything we, as CP growers, don't want in our mixes, but uses some pretty harsh acids. I have modified this process using distilled vinegar as a cheap and safe acid.
I start out with my sand blasting silica sand.
Not too much in any one bucket because I need to vigorously stir it.
Then I rinse it in tap water several times, stirring it each time, to try to get it as clean as I can.
It's shockingly dirty at first.
But gets better after about a half a dozen rinses, but not perfect.
I know that many of my remaining particles are larger because they settle out pretty quickly. And after less than a minute you can start to see the sand.
I use a rope with a couple loops to hold some fiberglass window screen over the bucket so I can drain as much of the water out as possible.
The rope goes around and through the first loop at the ends then back around most of the bucket and through the second loop to hold the screen on tight.
This system holds the screening on well enough to stand up to the weight of the wet sand. Some sand will make it through the screen, I use #16 screen sand, so I drain it into a tray.
After it dried out for about 20 minutes I can add the distilled white vinegar.
In it goes.
I stir the vinegar around to give it good contact with all of the sand, and then let it soak.
I let it soak for at least two days, and everyday I give it a stir. Which means everyday my arm gets to smell like vinegar. My wife loves it when I forget to stir the sand until right before bedtime. But the stirring is really important to keep the process going.
In between the stirring excitement I keep the bucket covered so my entire basement doesn't stink.
After a few days, 4 in this case because I didn't feel like doing much besides agitating it, it looks like the vinegar has done nothing.
But wait. Give it one more good churning - it's disgusting!
An astonishing amount of the sand has dissolved off minerals and solutes. All of the would have otherwise been lurking in the pots and trays. Slowly building up and causing my plants undue suffering. A few more rinses to get the vinegar out along with all of the liberated nasties.
After the last rinse with RO water to get any dilute the solutes from the tap water, and I am ready to set up the crafty draining rope and screen.
Then after 20 minutes of draining out.
I make good use of the tray, and spread the sand out for drying in front of a fan. Done. Cleanest sand you'll ever have.
Okay, so I am sure you are asking yourself "This seems like a lot of extra work. Is this really useful at all?" Well founded skepticism, I like it!
The short answer is - no. The sand I get is pretty cruddy. It's the best I can get for a reasonable price around here, and it needs work. The other thing is that I'm not growing big plants like neps and sarrs in this. Most of my plants are small dews or utrics. They can take a big hit if the solutes are high, or if there's enough nutrients to encourage algal growth. So, I do it. I don't think everyone must or necessarily needs to, but if you do give it a try, you might be surprised what solutes lurk in your "washed" sand.
The silica sand I can get near me still has a shocking about of solutes associated with it, and it is contaminated with alkaline sand. Not much I can do about that, it's all locally sourced around here and our water is pretty hard. What I can do is get rid of the problem by acid washing the sand.
Acid washing is done on small glass beads for micro-nutrient studies of plants that won't grow well in hydroponic culture. It gets rid of pretty much anything we, as CP growers, don't want in our mixes, but uses some pretty harsh acids. I have modified this process using distilled vinegar as a cheap and safe acid.
I start out with my sand blasting silica sand.
Not too much in any one bucket because I need to vigorously stir it.
Then I rinse it in tap water several times, stirring it each time, to try to get it as clean as I can.
It's shockingly dirty at first.
But gets better after about a half a dozen rinses, but not perfect.
I know that many of my remaining particles are larger because they settle out pretty quickly. And after less than a minute you can start to see the sand.
I use a rope with a couple loops to hold some fiberglass window screen over the bucket so I can drain as much of the water out as possible.
The rope goes around and through the first loop at the ends then back around most of the bucket and through the second loop to hold the screen on tight.
This system holds the screening on well enough to stand up to the weight of the wet sand. Some sand will make it through the screen, I use #16 screen sand, so I drain it into a tray.
After it dried out for about 20 minutes I can add the distilled white vinegar.
In it goes.
I stir the vinegar around to give it good contact with all of the sand, and then let it soak.
I let it soak for at least two days, and everyday I give it a stir. Which means everyday my arm gets to smell like vinegar. My wife loves it when I forget to stir the sand until right before bedtime. But the stirring is really important to keep the process going.
In between the stirring excitement I keep the bucket covered so my entire basement doesn't stink.
After a few days, 4 in this case because I didn't feel like doing much besides agitating it, it looks like the vinegar has done nothing.
But wait. Give it one more good churning - it's disgusting!
An astonishing amount of the sand has dissolved off minerals and solutes. All of the would have otherwise been lurking in the pots and trays. Slowly building up and causing my plants undue suffering. A few more rinses to get the vinegar out along with all of the liberated nasties.
After the last rinse with RO water to get any dilute the solutes from the tap water, and I am ready to set up the crafty draining rope and screen.
Then after 20 minutes of draining out.
I make good use of the tray, and spread the sand out for drying in front of a fan. Done. Cleanest sand you'll ever have.
Okay, so I am sure you are asking yourself "This seems like a lot of extra work. Is this really useful at all?" Well founded skepticism, I like it!
The short answer is - no. The sand I get is pretty cruddy. It's the best I can get for a reasonable price around here, and it needs work. The other thing is that I'm not growing big plants like neps and sarrs in this. Most of my plants are small dews or utrics. They can take a big hit if the solutes are high, or if there's enough nutrients to encourage algal growth. So, I do it. I don't think everyone must or necessarily needs to, but if you do give it a try, you might be surprised what solutes lurk in your "washed" sand.