Thread: Drum filter or combi

Originally Posted by Denise Doherty

Okay I have to admit that I’m fed up of cleaning sponges on the Oase 90000. It does a good job of filtering leaves and other bits but the sponges need cleaning several times a week. There is just so much sediment which proves the retro fit bottom drains are doing a great job but it would be easy to end up with another bacterial problem.
Now looking for a drum or combi drum filter to fit in the spring. The QK one looks great but I would love some real world feedback including reliability and customer service. The pond is between 16 and 18000 litres depending on how water level. Any plants have been repotted without soil and the pond is in shade for at least half the day.

unless the pond is small, combi units tend to have bio chambers that are too small.
though many people manage with smaller bios but usually end up adding showers to make up the shortfall due to nitrite or ammonia readings.

my own rule of thumb for bio size is 1 litre of K1 filter media per 50 litres of pond water. for average stocking levels. (1 x 60-70cm fish per ton of water)
this allows the bacteria to cope with change in seasonal bio load quicker, and more easily, than a smaller amount of media with a higher density of bacteria.

at 18000 litres (4000 gallons) i would be looking for a bio that will hold around 300 litres of K1
so you would be better off with a drum and separate bio imo....something like a nexus 320 would be an ideal size.

I have had the QK25 for just over 3 years now, and untill very recently only replaced one drum seal...

then a week or so ago the drum motor failed (3 years is apparently not an unusual life expectancy) and this caused the main pump to be starved of water and to cycle on and off and fail too.
then my booster pump also started leaking so had to replace that as well...so they are not cheap to maintain. but i'd still have one due to the labourious dirty work they save.

Queni had all the parts in stock so that was good,
but the drum motor is £250,
TIP booster pump from a different supplier £95 (£150 from queni koi)
drum seal £60