sand vs water

[kelvinlee]

Hi there,

I am going to start putting in the sand into my 4ft tank would like to know whether which is heavier water or sand.

What I want to do is to fill the behind portion of the tank with a the clear plastic in the form of a small rectangular box so that I can reduce the amount of sand used. The water will rush into the box cos the bottom is hollow.

The question is whether sand is heavier than water or not

[tawauboy]

yes, sand is heavier than water.

[CT]

sorry to ask, why must u make a hollow at the behind portion of the tank below the sand?

[kelvinlee]

As I cannot post pic here, please refer to this link http://www.aquarealms.com:/viewtopic...=101235#101235

[hwchoy]

come on! how much can sand cost?

[quote:9e16008676="kelvinlee"]The question is whether sand is heavier than water or not[/quote:9e16008676]
actually the correct question should be: “is sand denser than water.”

[budak]

errr... your diagram is clear enough, but could you elaborate on why you wish to set up the tank this way, instead of the more usual gravel/base fert bottom? There won't be any air underwater in any case.

[vinz]

Gravel is roughly (very very roughly) 1.2 times as dense as water. So how much weight will you save for that space?

According to your specs, your total substrate without the hollow area is about 75litres. Assuming you replace half of that with the hollow, the difference in weight is only 7.5kg.

Also, its a 4ft tank... which usually means a few large plants. They will do better with a thick substrate. If you don't want too much base fert, then put a slope of gravel as the bottom layer, followed by the base fert then another 1 to 2 inches of gravel.

I'm also wondering if a body of stagnant water under your substrate might pose any problems in the long run.

[juggler]

From personal experience, even if you create a slope, it could level out over time as you rescape your tank.

[kelvinlee]

Hi thanks for your reply. If you have been to CR aquarium at Tagore Lane.
They are using clear persplex to hold the sand in place. They use glue to paint over the persplex and then springler sand onto the glue making look as though it is a sand layer very nice.

I am now giving up the idea of the box cause me too have the same worry as Vinz if I am going to plant some plants that need deep rooting at the background.

[hwchoy]

I think their purpose was to create a terrace, not to replace the sand.