# Gravel Vac for Eco Complete?



## Mr. Fish (Oct 24, 2007)

Do they make any Gravel vacs that the diameter of the hose is small enough to
get under the substrate w/out sucking it up?


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## DonaldmBoyer (Aug 18, 2005)

I'll make it even easier for you: NEVER vacuum your gravel!!! I never have. You end up sucking up beneficial bacteria.

IF you further decide that it is necessary, then buy one with a very large uptake; the pressure of the siphon action will be more reduced over a larger intake, NOT a smaller one.


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## Mr. Fish (Oct 24, 2007)

I know your not supose to vacum and allow the mulm to build up,
but I have 2 goldfish which are generally not recomended for Planted tanks,
and I just dont think the plants would be able to keep up and transfer the massive waste 
that the goldfish produce....

Also I could be wrong, but find it hard to beleive that a larger diameter hose would
not suck up the EC as much as a smaller one... Please explain...


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## Cliff Mayes (Jan 29, 2007)

It almost seems counter intuitive for a larger diameter tube to have less pressure but it is true. You are putting the same amount of pressure through more space so it is not quite as strong. Remember bigger is usually easier but you will eventually end up with lots of different diameter hoses and siphons.

I have Goldfish too and still do not know if lots of plants can balance out the fish output.

Vacuuming up the excess, unsightly debris does not mean you must suck up the substrate. While it is true that some substrate will be sucked up, if you catch your water and crud in a pail the little bit of gravel can be put back in the tank after you pour off the water and crud.

So carefully vacuum the bottom to suck up anything you don't like and leave the rest alone. I think that is what you were being recommended to do.

It is common for experienced folk to take too much for granted. It is easy for almost anyone to assume some basic thing that another inexperienced person can totally misinterpret. The best thing to do is listen and keep asking questions.

Sorry for jumping in here like this, but it seemed like a good thing.


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## houseofcards (Feb 16, 2005)

There might be some confusion here. I think Donald is referring to the wider head of the gravel vac and not the tubing itself. Wider tubing will be more powerful than a thinner tube. Many times I vaccum clean my nano with airline tubing 1/8" around the foreground plants. If I used 1/2" filter tubing everything would get sucked up including the plants. But the wider head would decrease pressure within the head. 

Whether you have to gravel wash really depends on your tank. If you have open spaces and large waste producers like goldfish I would definitely gravel wash what you see. One trick so the finer eco doesn't get sucked up is to squeeze the tubing behind the hard plastic head as your cleaning. You'll notice the eco will fall back into the tank. After a while you will know how much to squeeze so just the lighter waste goes up. This is what they do with saltwater tanks so they can clean the sand and not suck it up.


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## Mr. Fish (Oct 24, 2007)

Cliff Mayes said:


> It almost seems counter intuitive for a larger diameter tube to have less pressure but it is true. You are putting the same amount of pressure through more space so it is not quite as strong.


I'm sorry Cliff but that doesent make sense whats so ever.
It would not be the same pressure, larger diameter hoses siphen more quanity
of water bringing more pressure to the hose due to a greater speed of force.
Also I have tried the difference between the two and the bigger hose sucks alot
of my gravel up...
I'm thinking of having the water siphen thru one of those aluminum strainers
with the lil mini holes, then hopefully it will catch all the gravel that was sucked up
during the water change and I can just run the tap over it and clean out the waste...
I'm just gonna have to get rid of these Goldfish...


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## DonaldmBoyer (Aug 18, 2005)

You don't have to get rid of the goldfish! Their waste will be broken down by the bacteria in the substrate/filter, and the plants will use those by-products. What size tank are we talking about here? And I was referring to the gravel vacuum "head," though I think any sized tubing would suck up the gravel seeing how the weight of the water used to siphon is the same. But now, we are starting to get a bit "geeky" about this, aren't we?


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## Cliff Mayes (Jan 29, 2007)

Sorry about the bad wording.

My backround is not Engineering so someone with a better handle on fluid dynamics (maybe a plumber) can probably better explain the Physics here.

I probably shouldn't have used the term pressure.

I think that Donald and I were thinking of the larger diameter tube on the end of the tube rather than just the tube itself. Most tubes are about one half inch inner diameter (some a bit smaller or larger) and the weight of the water is what is pulling the water up the siphon hose. Actually the pressure on the waters surface is pushing the water through the hose but whatever. The whole process is powered by the weight of the water in the part of the tube below the surface of the tank.

If you have the same volume of water going through the hose and expand the diameter you get a larger amount of water trying to go through the tube, which does not happen, and *you get a slower movement of water in the wider part* trying to crowd into the narrow tube. The speed of the water flow is what carries the junk, and sometimes the gravel, unless you pinch it off, to slow down the water speed, as has been advised. Theoretically you could have a very large size bell or pickup tube, on a normal size hose, that would have a very low flow rate which would not pick up much at all but a large siphon would not be very easy to move around a well planted tank.

I have EC mixed in with some black sand-blasting sand in one tank and no matter how careful I am, there is still some substrate that gets in the buckets. In a smaller tank like a twenty it is typical to suck out a lot more water than I need to, even doing half the tank at a time. The larger tanks work out a bit better because not as great a percentage of the tank volume is removed even though it is about the same amount of water.

The use of a small hose to work a small tank is because of the flexibility and size and the water speed is fairly fast but there isn't much of it. Usually I tape a piece of rigid tube onto the flexible hose to do this. The flow rate is affected by the friction of the water on the walls of the tube. A smaller tube has a much greater percentage of surface wall to square area than a larger tube. Because of this the water flow is not as high as you might think.

I hope this makes things more clear. Like I said this isn't my field but I have sucked up a lot of tank water and have watched a lot of tank stuff and WCs have been important for a long time.


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## Mr. Fish (Oct 24, 2007)

DonaldmBoyer said:


> You don't have to get rid of the goldfish! Their waste will be broken down by the bacteria in the substrate/filter, and the plants will use those by-products. What size tank are we talking about here? And I was referring to the gravel vacuum "head," though I think any sized tubing would suck up the gravel seeing how the weight of the water used to siphon is the same. But now, we are starting to get a bit "geeky" about this, aren't we?


Thats not the only reason why Im getting rid of the Goldfish, actually im upgrading my
tank to 100 gallons fully planted with Pressurized Co2. So being that my Goldfish
has been around awhile I think i'll end up runnin both tanks at the same time...
Its just the goldfish get me frustrated by tearing up plants and what not...
They dont even eat them, they just like to tear them up...and im trying to dose
ferts and trim all carefully for them to just tear it up.... it gets frustrating but I was
warned so I can only blame myself... but for the 100 gallon im going with tropical schooling
fish and will start learning more on Aquascaping...


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