Oase BioMaster Thermo 250


Up To 250 litres
Suitable for aquariums up to max. l 250
Dimensions (L x W x H) mm 240 x 240 x 370
Rated voltage 230 V / 50 Hz
Power consumption filter + heater 15 + 150 W
Net weight kg 5.20
Guarantee (+ request guarantee) Years 3 + 1
Max. flow rate l/h 900
Max. head height, metres m 1.30
Hose (quantity/length) 1 UNIT/4 m
Connection for hoses ø (inner/outer) 16 / 22 mm
Filter volume litres 4.4
Pre-filter volume litres 0.40
Suitable for freshwater Yes
Suitable for saltwater Yes

In stock


*Free shipping on orders over £40 (*may exclude some aquariums)  Geographical restrictions may apply


Our stock levels are live and accurate to within 15 minutes. If something shows as in stock, rest assured – it is in stock and available for purchase.

Oase BioMaster Thermo 250 external filter for tanks up to two hundred and fifty litres. Made from high quality materials the Bio Master is robust and also has a very modern look. Designed to provide mechanical, biological and also chemical filtration if you wish. External filters are in general much the same but the Oase Bio Master Thermo 250 differs slightly. The Bio Master comes equipped with an easy to clean pre filter that can be cleaned without opening the filter. The pre-filter consists of high grade foams that trap most of the debris.  The idea is that the debris removed by the pre filter extends the service interval of the main filter.

The Oase BioMaster Thermo 250 main filter.

The filters main section features two foam filter stages prior to the Hel-X media filled bio’ stage.  Hel-X 13, specially designed for use within the Oase Profi Clear Premium Moving Bed Module and Oase Profi Clear Premium Compact range of Drum Filter systems. So I would swap that out for a much better media, such as Seachem Matrix  Or Eheim Substrat Pro. Pretty standard view in the trade and hobby.

Seachem Matrix 1L

Eheim Substrat Pro 2 ltr

Oase BioMaster Thermo 250 Features

Pre filter we have already covered. The best bit in a word, handle, great job Oase all filters should have a carry handle makes life so much better. Auto shut off and lock, that prevents water loss when the pre filter is removed. A built in primer for easy priming and start up. The all in one shut off valve, also used for flow control. Easy service for the main filter, simply slide of the all in one valve block and release lever unclip the catches and clean.

Built in heater.

The Oase Bio Master Thermo 250 is just the 250 Biomaster with an Oase HeatUp 150 Watt Heater fitted. In the head of the normal 250 there is a gland that allows you to add a heater, the thermo comes with the heater fitted.

There are other models such as.

Oase BioMaster Thermo 350


Oase BioMaster Thermo 600

Oase-BioMaster-Thermo-manual-download English


The ultimate convenience among the external filters for aquariums. The external filter meets the highest demands in water filtration and filter cleaning. The combination of highly effective biological filtering with Hel-X and mechanical/biological cleaning with filter sponges ensures healthy and clear aquarium water. The BioMaster is suitable for aquariums with a volume of 250 to 850 litres. No complete cleaning needed: the EasyClean pre-filter chamber enables convenient filter cleaning. The automatic shut-off and safety lock prevent unwanted water leaks, e.g. when removing the pre-filter module. A practical venting button makes the water suction highly effective and allows for a quick and convenient start. The complete set includes filter media, hoses, adapters, suction and discharge pipes as well as the water diffuser. The BioMaster is available with or without an adjustable heater.


  • High filter volume:

    The combination of highly effective biological filtering with Hel-X and mechanical/biological cleaning with filter sponges is ideally coordinated to ensure healthy and clear aquarium water. The water flows through the pre-filter first, ensuring an extra long service life.

  • Complete set for a quick start:

    Including filter media, hoses, adapter, flow regulator, suction and discharge pipe as well as water diffuser.


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We aim to dispatch all orders placed before 2pm the same day and orders placed after 2pm on the next working day.
While we typically ship orders the same day or the following working day, as with any company that relies on couriers, we are unfortunately unable to guarantee a delivery date and time and that orders will arrive the following working day.

  • 1st Class mail is aimed to be delivered the next working day after dispatch.
  • 2nd Class mail takes around 2-3 working days after dispatch.
  • APC Next Day delivery is usually delivered the next working day after dispatch to UK mainland postcode. Items to more remote areas may take longer.

* If your order is over £40 excluding livestock, you qualify for our FREE delivery to UK Mainland postcodes. This excludes Northern Ireland, Isle of Man, Isle of Wight, Isles of Scilly, Channel Islands and Scottish Offshore postcodes. FREE delivery is available for Scottish Borders postcodes but you will still need to pay the appropriate surcharge.


You have the right to cancel an order within 14 working days of receipt. You must return the goods to us in new and unused condition in line with our Returns Policy. We must receive the goods within 21 days of the notice of cancellation during which time you are responsible for any loss or damage. Once received in new and unused condition we will refund the purchase price. If the goods arrive back in any less than the condition they were sent out in, they will be returned to you and no refund will be processed.


To return goods you need to use our returns form and we will contact you to acknowledge you are sending the goods back to us. Goods being returned for testing must be sent at your own expense. We will only refund postage fees if the order arrives damaged or becomes faulty within the first 4 weeks. It is important that you obtain proof of posting as the goods are your responsibility until they are received by us. We can only refund postage costs if goods are returned within 7 days of purchase under the Replacement Policy. You need to agree a delivery service prior to shipping as we will only refund standard or tracked shipping fees, we are not able to refund the cost of any special delivery service. We cannot refund postage for goods returned for any other reason and we reserve the right to deduct our original postage cost from any refund applicable. If you have made a mistake in the purchase, then you will need to return the goods to us.