Ballotini glass beads
 

My first impression of having a glass sand bed is the whiteness of the sand and sparkles under good lighting. My idea of having a sparkling white sand bed.

Glass beads have several advantages over regular coral sand.

Glass beads being inert would not break down and is chemically inactive. It also would not absorb phosphate or any other heavy metals which is the primary concern of DSB users in US.

It is also much heavier than coralsand thus settle within hours after washing. I wouldnt be concerned about surface area as these glass beads are much finer than C0 sand with a size of 0.15mm to 0.09mm.

DSB height can be reduced due to the fine size and mud texture of the glass beads.

I used the ballotini impact spheres manufactured by Potters Industries Inc in Austrialia.

Typical Properties:
Shape - spherical
Color - clear
Hardness (Knoop) - 515
Compressive strength - 36,000 psi (avg.)
Density - 2.5 g/cc
Specific Gravity - 2.45-2.50
Free silica content - 0%


I used 2 sizes for my sand bed.

Size 10, US Sieve 100-170, micron 150-90, roundness 90%
Size 3, US Sieve 20-30, micron 850-600, roundness 65%

Full Specs can be found here

The Size 10 glass beads are so fine that it pours like liquid and have a mud texture when wet. There are no risk of cuts from the glass beads as they are too fine to even scratch yr skin.

As the glass beads are so white, any impurities would be an eye sore. I ran a strong magnet over the glass beads and hardly picked up anything. A closer look at the sand revealed glass of different colours. There are some yellow and black glass beads among them.

Most of the impurities will float in water so all you need to do is to stir them up and pour away the top portion of the water.

Another interesting feature is that it looks so natural. The waves and pattern will form naturally on the sandbed with my return and a powerhead. I covered the Size 10 with Size 3 because I get whirlpool with just a 2000L/hr powerhead. Being so fine, the sand actually got picked up, whirl and picked up even more sand like just a real tornado! I spent 1 hour looking at this strange sight. http://www.sgreefclub.com/forum/html/emoticons/ohmy.gif

Then I realised I'm in deep shit, there is no way I can get clear water with so much acts of nature. I bought another pack of Size 3 beads and laid them over, water cleared within 4 hours.

These glass beads are quite glaring to look at under MH lights as they reflect light and sparkles. SPS maybe able to get some light underneath due to this reflection.

To give you an idea how glaring it is to look, here's a pic with 250watts 10000K BLV on the right side of the tank. This shot is taken without flash with EV -3

A pic of the glass impurities under my F717.

The cost of the glass beads are $1.4/kg. They come in 25kg packs so each pack will cost $35. Corals sand cost about $0.6/kg and comes in 10kg packs.

You will not be able to purchase these glass beads from hardwareshops. Its only available with sandblasting suppliers and have a certain min order before shipping. It is best to order under a sand blasting company's name as you will get a cheaper price.

Becareful to ask for spherical glass beads as there are glass chips in the market. The glass chips are very rough and have the tendency to cut however they cost only $0.4/kg

Sad to say, this project will be terminated soon. I'm going to get my tank replaced and going to throw away the sand due to ISOPODS contamination.

Summary of this short lived project.

Size10 is too fine to be used

The glass beads must have flat pieces of liverocks buried to lay the foundation for the LR as the beads will move if you have a strong powerhead (tunze).

Bubbles will rise among the glass beads and will carry a few glass beads together with it. The bubbles will then pop and release the beads all over the place.

Unfortunately, I'm unable watch this sandbed matures and do not have the luxury to spend another fortune buying them. http://www.sgreefclub.com/forum/html...ons/crying.gif

Latest update.

After I dumped most of them, I still left a 2inch layer under my current 4ft. So far I have undetectable nitrates despite having a sandbed of around 3inchs only.

I conclude that the dense glassbeads to have powerful denitrification. When they were removed, hydrogen sulphite were released (rotton egg smell). For those that wondered why I had undetectable nitrates despite of no skimmer, no refuge ... this is my secret! ;)

Thanks for sharing!

It looks nice but expensive to use.:p

not really expensive to use .. considering it can give you powerful denitrification