Gravel Vac

[Benihana]

Hi all.

We've got one of the, supposedly, self starting gravel vacs. The tube which by all accounts you pump a few times with it submerged and it starts to syphon. I can't get any bloody pressure at all with the bloody thing and all that keeps hapening is i'm spreading what waste there is around the tank. I spoke to my LFS and they suggested the tried and tested 'suck on the hose' approach. I've just tried that when I got home form work and it is the same result. Am I making a schoolboy error that I can't see? I've followed all the instructions. I want to get one og the powered vacs but my LFS said they are rubbish. Any feedback on them or techniques I should be employing would be really appreciated.

 

[Richard James Patrick]

Howya, okay I'm going to describe the "suck on the hose technique" sounds rude but let's not go there. The Vac part of the device should be in the water before you start. The bucket or what ever you dumping the waste water into needs to be below the base level of the tank ie on the ground. The hose leading from the Vac goes into this bucket. Now to start the syphon begin sucking until the water in the pipe comes below the base level of the tank (do it in one go if you can). It helps if you crouch down so that the pipe end is near the bucket. Make sure you stop before it reaches the end or it's a taste of fish juice for you.
That should do it.

Hop that makes sense, it did in my head.

 

[Matty P]

GRAVITY! hey not bad from straight off your head. Fish juice isn't the nice juice in the world !

Sorry to hi-jack this thread but... can you use a gravel vac on sand

Cheers Matt

 

[Aphotic Phoenix]

Sorry to hi-jack this thread but... can you use a gravel vac on sand

Yes, the technique is just a little different. You move the vac in circles slightly above the sand to draw the waste up into the vac instead of putting the vac directly into the substrate.

 

[Matty P]

OK thanks, i'll keep that in mind

 

[mark.w.jones]

Your gravel vac is in 2 parts. A hard plastic cylinder joined to a flexible hose with a one way valve between the two. The larger the diameter of the flexible tube the harder it is to get the flow going. Consequently the smaller gravel vacs are easier to start than the larger ones. The other problem is how high above the water level the one way valve is. The higher the one way valve above the water surface, again the more difficult it will be to get the flow going.

Ideas which help include.

1. Buying the correct sized gravel vac for your tank. The deeper the tank the bigger you need and vice versa.
2. When you pump up and down to get the flow going try to keep the one way valve at the top of the hard plastic cyclinder as close to the surface as possible. This may mean holding it at and angle as you pump.
3. If all else fails. Hold the bottom of the gravel vac just above your gravel. Get your bucket and end of flexible tube as far below bottom of tank as you can. Then give a large suck. Water in the mouth is usually unavoidable. Also make sure no bottom dwellers or shrimp end up under the end of your gravel vac before you suck or you could end up with an unwanted snack.
4. If this still doesn't work, there is either a faulty valve or a leak somewhere in your gravel vac. Take it back