Eheim Quick Vac Pro Model 3531

Very easy to put together, nice clear instructions, batteries included, estimated 4 hours life from the batteries. Feels very solid, but not too heavy. Easy to move around the tank, a bonus not having the pipework to a bucket so you can watch what you are doing without keeping one eye on a bucket. I have tested the quick vac on the following of my tanks.

Oscar tank: Substrate 2mm sengal gravel.
Works well on large debris (oscar poop). Very easy to use, not as awkward as I thought it was going to be, and quiet too, so did not disturb or upset the fish too much. My initial worry was my oscar attacking the vac as he does with the syphon and biting through the mesh, but he behaved. The gravel did not clog in the vac, although this finer gravel normally does not, dirt was lifted into the container, but after a while the tank started to mist.

Second Oscar tank: Substrate 2-3mm smooth dorset pea gravel.
Water change & Clean due on this tank so dirtier conditions. Sadly not as impressed on this substrate as in the first tank, again large poop on the top of the gravel picked up very easily, not as much as I expected brought up from under the gravel. Also the water around the vacuum seemed to cloud up with bits disturbed from the bottom, and from the debris container.

Small Turtle & Plec tank: Bare bottomed tank, with a few large pebbles. Lower water level.
Works very very well on a bare bottomed tank, got all the poop up straight away, took 10 minutes to do a 3ft x 15″ tank, sadly again leaving the tank a little cloudy, nothing the filter did not clear up in an hour or so.

Coldwater tank: Large “garden/driveway” type 10mm gravel.
I am impressed how the Ehiem coped with larger gravel, normal syphon type gravel vacs clog up with this larger gravel and more time is spent tapping it back out again, used for 20 mins, did the whole 5ft x 20″ tank bottom without clogging once, very impressed with that. However as I found as with the other tanks, the cloudiness created is annoying, not hugely cloudy, more misty. The section that catches the debris & poop does hold a lot of it in, but the cloudiness gets worse the longer it is in use as poop it is getting broken up inside and liquidised by the water jets sending it back into the tank.

Large Plec & Cichlid tank: 2-5mm Aquarium gravel.
Only used for a minute or 2, hoovered up a huge long plec poop very quickly with no effort, however once it was spun round in the chamber it started to break up very quickly to a gooey brown mess that started to come through the filter section.

Small Tiger Barb tank: 2-3mm smooth dorset pea gravel.
Much better on a tank with smaller fish, a little misting once the debris holder had some debris in, I found keeping a bucket of warm water nearby and unclipping the holder and giving a quick wash in the bucket stopped a lot of the clouding. Much more suited to smaller fish.

The Eheim Quick Vac is great idea in concept. Nicely put together and sturdy, but the holder for the debris lets it down with only a small amount of poop inside it starts to cloud the tank. However, this was tested on my tanks containing large messy cichlids and a large 18″ plec so it had a tough testing. If the container for the poop could be double layered with the mesh and some filter wool in between it would do a much better job for a longer clean for larger fish. The tank with smaller fish the clouding did not occur as quickly as on the tanks with larger fish, again not ideal for a full tank clean. However it is ideal for what it says a quick vac. For a good clean out you need a bucket of clean water to wash out the debris compartment every couple of minutes, or wash it out under the tap.