Hydor Seltz L30

Medium flow waterpump – Joe

SUMMARY: Cost effective waterpump for medium flow systems.


Power consumption: 23 watts (US version); Fittings: 1/2″OD (13mm); Dimensions without fittings: 4.5″ (114mm) x 3″ (76mm) x 3.5″ (89mm) height.

The good guys at Cooltechnica were nice enough to send over a waterpump from a manufacturer I had not known called Hydor. They are an Italian company which produce a full line of aquarium, fountain and pond pumps. The model Cooltechnica sells is the Hydor Seltz L30.

Hydor L30 is suitable for either inline or submersible use – personally, I prefer inline – it results in a more compact installation. The performance curve starts at 336 gph @ 0′ head:

L30 PQ

Graph courtesy of Cooltechnica/Hydor.

Cooltech graphed a comparison to EHEIM pumps:


Graph courtesy of Cooltechnica.

Based on specs alone, the L30 is about the same as EHEIM’s 1250. I opened the pump up to take a peek inside:

Pump 3

No magic here – the impeller is removable and spare parts are available – always a plus. As a magnetic drive pump, the impeller is the only moving part.

For in-line use, I used the two fittings for 1/2″ hose; the blue piece at the front of the pump secures the cap for the pump chamber. All joints are sealed with “O” rings. Ready to go, it looks like this:

Pump 2

Some users might elect to use the rubber suction pads – I prefer to mount a pump on a piece of foam for noise control.

In running the pump, I did notice a slight “rattling” sound; with more resistance in the system, the sound increased slightly, but not to a level that I would consider objectionable. Sound dampening is a must, as it will resonate noise if bolted to a case. Compared to my EHEIM 1046s (totally silent), the Hydor L30 is noticeable.

I did find that the L30 does not tolerate much air in the line – especially when first priming the hoses. I suspect that it may be cavitating in such a situation.

I ran the pump for about six hours straight and its body did not heat up too much; I’m developing some tests to measure how much heat a waterpump dumps into the water – stay tuned.


Priced at around $50, the Hydor L30 looks like a very competitive waterpump for medium flow systems. Spare parts are available – always a plus.

Thanks again to Cooltechnica for sending this our way.

Email Joe

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