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Oase filtosmart thermo 100 - problems


New Member
6 Oct 2020
High Green
Hi all,

I'm having some technical problems again - this time with my filter. So since I set up my Aquael shrimp set smart 30l I've been having some problems with inadequate water movement around the tank. I bought an Oase filtosmart thermo 100 to upgrade the filter that the tank came with and I bought some nano glass lily pipes to use with it, but when I set it up tonight I couldn't get the filter to work at all. It isn't drawing any water in through the inlet pipe. I filled the filter with water and even put it next to the tank to make sure the height difference wasn't too great, but nothing did the job. Any thoughts on what I could be doing wrong?


Last edited:

Diogo Sousa

23 Jul 2017
SE London
Sounds like the filter is not primed properly. If water doesn't reach the impeller then it won't work.
Does it have a priming mechanism? If it doesn't you'll have to prime it yourself.
What you want is for water from the tank to be siphoned from the intake into the canister, much like when you drain the tank when doing a water change. Here's what I would do:

- Empty water from the filter and place it under the tank. Make sure the heater is in and the hose connector part is out. Outlet hose can stay attached but disconnect the inlet.
- Prepare a bucket and towel, things can get messy if you're not careful, you'll have a tank wanting to drain itself!
- Get a cup with boiling hot water. Make some tea since you're putting on the kettle anyway. ;)
- Now you just have to start the siphon. Make an U bend on the tubing, the lowest part of it should be just under the tank and the tip should be above the water level. Suck on the intake hose until water is in the tubing, no need to get water in your mouth. The water level in the tank and in the tubing become the same, that's why it's handy if the tip is above the water level.
- At this point you'll have a siphon. I like to dip the tubing in hot water to make it easier to connect to the filter but it's not handy when it's already full of water wanting to go on your floor so you may want to dip it beforehand.
- Connect the tubing to the hose connector part of your filter, the less air in the tubing the better. Connect the hose connector to the filter and lock it in, water should start draining from the tank into the filter. When it's done your filter will be full. You can then plug it in and it should work!

Good luck and let me know how it goes.
Last edited:

Andrew Butler

1 Feb 2016
Banbury, Oxfordshire
even put it next to the tank to make sure the height difference wasn't too great
I think here quite likely lies your problem. ;)
If you can get the filter a little lower than the aquarium itself, just to start things off you might find it easier. I've one sat ready but not gotten around to trying it yet, I have been told it can be a fiddle getting things going though when running them sat alongside your aquarium though.
Update us of how it goes.


Global Moderator
14 Dec 2008
Hemel Hempstead
Hi Emma
Best if you try and fill the cannister full of water!
Remove the heater and pour some water into the heater space till it reaches near the top of the opening!
You may displace some water when replacing the heater...so have the filter on a tray with a towel underneath...some kitchen towel will be handy for spillage!

Try switching it on to see if it will run first time!

If you can fill the IN Tube with water this will help pull the water through the filter if the above fails first time!

Open the connector, suck:eek: on the IN side of the connector best having a bucket handy as the flow with be quite fast, close the connector....Check to see if there is water near the surface of the connector compartment, attach to the filter....now the IN tubing should be full of water....and also the cannister!

Switch on, hopefully it will run....there maybe some air bubbles expelled...;)



6 Apr 2017
Before priming buttons on filters, I just used to suck in the hose on the pressure side. That way you draw water out of the tank, the siphon will start filling the canister (placed under tank) and you won’t get a mouthful of water.


30 Mar 2016
I have the Eden version of that filter. Make sure the inlet/outlet hose part it in the locked position otherwise it will stop the flow. Similar to the video, but just turns instead of having a latch.

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