Use of a Wet/Dry (Shop) Vac to drain and clear old tanks

Afternoon all,

Anyone have any experience of using a wet & dry vac (I think more commonly called shop vacs in the US) to drain and suck up small gravel and muck from old fish tanks? I have a few old tanks that I need to drain/clear and that seems the easiest way if it works.

I've downloaded numerous instruction manuals from manufacturers and while the instructions are clear that they can be used to suck up liquids (remove the dust bag, fit the wet filter) and to pick up dust and debris (use a normal filter, dust bag optional) it still isn't clear to me if the wet function is suitable for both simultaneously - i.e. sucking up water and wet gravel/sand in one go?

Couple of example pictures below (won't be vacuuming up the pebbles obviously...).

Thanks!

I have used a Karcher wet/dry when I got flooded some years ago....hoovered water, mud and goodness knows what else when the sewers backflowed/overflowed after heavy rain where I lived. No ill effects to the hoover, but it did need a really good clean and dry before being used for dry hoovering again

wasmewasntit said:

I have used a Karcher wet/dry when I got flooded some years ago....hoovered water, mud and goodness knows what else when the sewers backflowed/overflowed after heavy rain where I lived. No ill effects to the hoover, but it did need a really good clean and dry before being used for dry hoovering again

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That's really helpful, thanks. I'll give it a go. I can get a small one for £35 which I'll keep in the shed for future tank use only - so no major issues with cleaning it before using for general hoovering (although it'll be cleaned anyway for the smell!).

Thanks.

Just a word of caution here. The wet dry works wonders for sucking the last bits out of the tank but don't use it to suck all the water out of the tank because once it fills the tank you have started a siphon with the 2.5" or larger hose it can overflow the vacuum very quickly leaving you with gallons of water on the floor. Speaking from experience. Siphon off all the water using the normal syphon first then use the wetdry.

Uberhoust said:

Just a word of caution here. The wet dry works wonders for sucking the last bits out of the tank but don't use it to suck all the water out of the tank because once it fills the tank you have started a siphon with the 2.5" or larger hose it can overflow the vacuum very quickly leaving you with gallons of water on the floor. Speaking from experience. Siphon off all the water using the normal syphon first then use the wetdry.

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Good to know, thanks.

I'll drain the tank as much as possible first anyway, but more out of interest then anything would the siphon issue remain the case if it has a float valve? The one I'm looking at does. I'm guessing that just cuts off the electronic suction but the siphon action would continue independently - unless the float valve creates a physical barrier across the hose intake?

Linkandnavi said:

Good to know, thanks.

I'll drain the tank as much as possible first anyway, but more out of interest then anything would the siphon issue remain the case if it has a float valve? The one I'm looking at does. I'm guessing that just cuts off the electronic suction but the siphon action would continue independently - unless the float valve creates a physical barrier across the hose intake?

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I believe the float valve just enables a bypass valve and would not stop the siphon. Once the hose fills with water going over the tank top and below the tank water level a siphon will start and continue until air enters the hose or the shop vac tank water level is higher than the aquarium tank water level.

Linkandnavi said:

unless the float valve creates a physical barrier across the hose intake?

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That is what I thought but is is just a floating ball valve, that turns off the motor, it doesn't stop the siphon.

Thanks all. Bought the shop vac last night and it's worked a treat mucking out three old tanks