Causing calcification of knitting canvas (LLDPE mesh)

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In summary, a person may want to cause calcification of a sheet of knitting canvas in order to increase the surface area for an algae growth substrate. There are many possible ways to do this, but the most effective is probably to roughen the surface and then place the screen in a solution that causes the calcium to deposit.
  • #1
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I know this sounds like an odd question, but to me, it would be useful to figure this out, so I'm throwing this out there to see if it bounces off anyone.

I would like to know if there is a relatively simple way to cause calcification of a sheet of knitting canvas. The material in question is Darice #7 mesh (LLDPE), which you can get at any fabric store or wally world.

My reasoning for wanting this is related to an aquarium filtration system, mainly used in reef aquariums, that grows algae on a substrate for purposes of nutrient reduction. Right now, the standby material is the #7 canvas, which is vigorously roughed up with a hole saw or saw blade so that it is really prickly. The idea being that this 1) reduces the smoothness of the surface of the canvas, allowing algae to adhere faster and 2) gives a greater surface area for the algae to anchor on to.

But in my experience, the thing that causes algae to really get a foothold is calcification of the screen. This happens over time, so I purport that initially, the roughing-up will probably help algae adhere, but if over time this matters less and less, because as calcium adheres to the screen, this creates a microscopically rough surface that, even if disturbed from scraping off algae or scrubbing with a stiff brush, will allow for rapid regrowth of algae. For reference, the algae is removed from the growth substrate on a regular basis (7-14 days).

My goal is to figure out how to start with a calcified screen so that I don't have to wait 2 months for that to happen naturally.

I'm thinking that I could just take a wire brush to scuff up the material and get rid of the smooth surface, then place the screen in something for a period of time that would cause the calcium to deposit on to the screen.

I'm also assuming that it is calcification that is the key here. I haven't had a "mature" growth substrate analyzed or anything, it just seems to make sense.

Also I'm not opposed to using another material for the substrate, but it's got to be "reef safe" material.
 
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  • #2
The only approach I can think of at the moment is to leave the material covered with a thin layer of some solution to dry out. The solution must contain calcium ions and something that wouldn't be unsafe for the reef chemistry. Unfortunately, calcium carbonate is weakly soluble, so there is no way to prepare its solution of a reasonably high concentration. Perhaps start with dry CaO, add some water and leave everything in a CO2 rich place? Later rinsing will wash out hydroxide, so the final product should be safe.

That's just me thinking aloud.
 
  • #3
A commonly used dosing mixture is Kalkwasser, basically pickling lime, something like that? Could make kalk paste and place it in that. But I guess would something like that actually be so caustic (in paste form) as to dissolve the screen material itself?
 
  • #4
In general polyethylene is base resistant. Besides, even if its surface gets slightly etched, that's good - it won't be that smooth.
 
  • #5
I have another possible route I could go with this. Instead of causing a layer of calcium to build up on the mesh, what about this:

Dip the screen in something that would cause the material to soften
Remove the screen when it gets to the point of surface softness, but is still firm enough to maintain it's default shape (mesh)
Lay the screen in a tray full of fine quartz sand (like pool filter sand) and pour sand over the top, and press in
Allow "softened" screen material to re-solidify

The idea being that the screen would now be "impregnated" with sand on the surface that would not easily be brushed or scrubbed off

I tried doing this by heating up the screen, but the point at which the screen gets warn enough to allow for this to occur is also the point at which the screen turns into mush. So then the question is, what would do this? I'm guessing that it would be something nasty like toluene or xylene...hoping for another answer, one that is not quite so dangerous...
 
  • #6
I am not aware of any cheap and safe solvents that could do the job.
 

1. What is calcification of knitting canvas and how does it occur?

Calcification of knitting canvas is a process in which calcium deposits form on the surface of LLDPE mesh. This can occur due to a variety of factors such as exposure to high levels of calcium, changes in pH levels, or bacterial growth.

2. What are the potential consequences of calcification on LLDPE mesh?

The consequences of calcification on LLDPE mesh can include reduced flexibility and strength of the mesh, decreased permeability, and increased risk of bacterial growth and infection.

3. Can calcification of knitting canvas be prevented?

Yes, calcification of knitting canvas can be prevented by properly cleaning and maintaining the mesh, avoiding exposure to high levels of calcium, and controlling pH levels in the surrounding environment.

4. How can calcification of knitting canvas be detected?

Calcification of knitting canvas can be detected through visual inspection, as the calcium deposits will appear as white or yellowish spots on the surface of the mesh. It can also be confirmed through laboratory testing.

5. Is there a way to remove calcification from LLDPE mesh?

Yes, there are methods for removing calcification from LLDPE mesh, such as using acidic solutions or specialized cleaning agents. However, it is important to note that these methods may also damage the mesh, so prevention is the best approach.

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