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This post consists of two questions...

Question #1: Weight of 55 Gallon

I am concerned about the weight of my newest addition, my 55 gallon freshwater eel tank. Now, it sits on a nice prefabricated oak wood stand designed for the 55 gallon. My concern is with the weight of the water and aquascaping I have placed in the tank. The tank consists of 60 lbs. of Carib-Sea Marine White Sand, about 70 lbs. of lace rock, and the rest is water. I know the average weight of a 55 gallon filled with water is around 500-600 lbs. Or at least that's what I've always read. With the aquascaping I have, will the weight be ok for my stand? I know the sand and lace rock displace quite a bit of water, but still...it's a ALOT of rock and sand in there and it just came to me when I was adding the last pieces of lace rock earlier in the evening.

Question #2: Time it Takes for Driftwood to Sink

I've had four pieces of driftwood in the same 55 gallon tank for two weeks and they all still want to float straight up to the top. In the mean time, they are attached to a rock until they totally soak up water and submerge on their own. So, on average, how long does driftwood take to sink from your experiences? *Note - Each piece is about 12"-14"s.

1tankneverenuff

As far as taking driftwood to sink it depends on the wood some will never sink where as others will sink immediatly.

If it is the type that will not sink fix it to apiece of slate and that will hold it down. I have one large piece in my tank held down by a large heavy rock this has been there for about 18months and is still a bit unstable if I removed the rock. It is an extremly long lasting timber in water.

Keith

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It's your standard driftwood that can be found at many LFS. I don't know the common name nor the scientific name. I know it sinks because I have it in another tank and has sunk and my friend has a 55 gallon as well and his pieces sunk. The problem is we both decided to let the pieces sink freely LONG after they were purchased and placed in the tanks. This time, I'm trying to estimate how long it will take. Plus, the way it is placed in the 55 gallon right now just looks retarded 'cause all I can do is wait for it to finally sink...

I'm not much help with the driftwood. All the wood I've ever used sank in less than a day.

As far as the weight of the tank on the stand goes. I wouldn't worry too much.

Think about it. Yes there is a lot of weight in the amount of sand and rock you added. But both of them have displaced an amount of water that would prob be some what close to what the water weighs.

I'm not saying that the tank isn't heavier than it would be if just filled with water. I just don't think the difference is of much concern. As long as the stand was built properly. Of course.

Some wood take 2/3 weeks to sink & some take more than 8 weeks. I have a large piece in my tank, that took me more than 2 months to sink. I have some malaysian driftwood that is difficult to sink.




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Wodd sinking. Hmm. If yuo're lucky, and have a pice of wood that's denser than water to begin with, it should sink the moment it's soaked. All my wood pieces fall into this category luckily.

Trouble is, there are some pieces of wood that will remain bouyant even after a 2 year soaking.

Here's what you do.

Step 1. Fill a bucket that will take the piece of wood in question, with a known volume of water.

Step 2. Immerse the wood. Find out how much water volume it displaces. That will give you the volume of your wood piece. Ideally measure this in litres.

Step 3. Remove the wood, then weigh it. Obtain a value for the mass in some suitable units. Ideally, use kilograms.

Step 4. Divide mass by volume. This will give you a density figure. Convert this density figure to kilograms per litre using suitable conversion tables if you've used other units for your measurement.

Step 5. Water has a density of 1 Kg per litre.If your wood density is greater than this, it'll sink. If not, it will probably float. Some lighter pieces of wood become heavy enough to sink after a thorough soaking, but some wood types (e.g. balsa wood) are both extremely light and resistant to immersion. Which is why balsa wood is used for model boat making.

If your wood is less dense than water, you could have a problem.





Panda Catfish fan and keeper/breeder since Christmas 2002

It's been two weeks and no pieces have sunk...I'm getting worried .

You might have to cement them to pices of slate using silicone aquarium sealant then. However, you'll have to dry them out again before doing this! And let the sealant spend a minimum of 24 hours working before you attempt to relocate the wood in the aquarium.

If I were you, I'd go hunting for Mopani Wood. It's expensive, but it's very definitely heavier than water, and comes in a range of intricate shapes that make for excellent aquarium furnishings. I have one or two pieces in use now.

Just make sure you soak it thoroughly and boil it first. Otherwise you're looking at a significantly increased frequency of water changes to remove excess tannins from your aquarium. Which on a 55 gallon aquarium constitutes a fair amount of bucket lugging.


Panda Catfish fan and keeper/breeder since Christmas 2002

Think about it. Yes there is a lot of weight in the amount of sand and rock you added. But both of them have displaced an amount of water that would prob be some what close to what the water weighs.....I just don't think the difference is of much concern.

Actually there is a big difference. A 40 lb bag of sand or gravel, is less than 2 gallons of water displacement. And a solid piece of rock, even less. A gallon of water weighs 8.34 lbs, or 3.78 Kg. 2 gallons of water then weighs 16.68 lbs vs 40 lbs of substrate. In a 55 gal tank, I would suggest two 40 lb bags of gravel, so that would be 4 gallons of gravel, displacing less than 4 gallons of water (less because gravel not solid, and much open space in the gallon container). So a difference of almost 50 lbs, or more considering the difference of unused space of the gallon container with the substrate in it. A solid rocks mass could increase these numbers by 5 or 6 times as much. So, in the end, the rock and substrate differences could be hundreds of pounds of differences in the end. Just for a general idea of solid rock weight;
a cubic foot of water weighs 62.4 lbs.
a cubic foot of limestone weighs 165 lbs.
a cubic foot of sandstone weighs 150 lbs.
a cubic foot of granite weighs 175 lbs.
The rocks are generalized average weights.

HTH....

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There is always a bigger fish...

The tank has been holding for 3 weeks, and so far so good. But, if it were to ever break...it would be like a hurricane went through my house and flooded it .

A tank should hold with rocks in it. I've seen pics of a 55g that was filled with several large rocks, and then filled to the brim with gravel, and then water. They had it on display somewhere just to prove that a tank and standard stand will hold that kind of pressure I don't think you'll have any problems with it...but if you do, it should be covered under warranty (but they won't pay back the damage done to the rest of the house...just the stand and tank).

You should probably boil the driftwood if you can. I had one of my friends boil my driftwood in a turkey fryer for me (the wood is about 18"-20" long I'm guessing) because it was too big to fit in a pot to boil. The boiling will get most of the tannens out and make it sink a LOT faster. I had my driftwood soaking in a bucket for a week or 2 before I had my friend boil it for me...it sank as soon as I put it in my tank after boiling.

Good luck