Should I put scrubbies in the bottom of my Hozelock Cyprio bio-filter?

Recently I got an email from someone asking about Cyprio bio-filters. It was much along the lines of the problems I have encountered and written about in my Ponding website.

"Hi ....just been reading your page on how to make a pond filter ...very informative ...wish I had found it before buying the Hozeloc Cyprio off Ebay , Although it seems to be working ok (I have checked size and thats fine) it does need the foam cleaning (I rinse it as instructions say using the water from the filter) every couple of days...my point in emailing you is to ask if you think putting some "scrubbies" in the bottom of the filter will help increase my bacteria population ? There are already some black ball things in there ....but not many......and not a lot happening to them....pond is new and has been going for about 2 months . I recently had the water checked and found I had traces of ammonia .25 . I was told this could sort its self out as the pond matures but thought I could give nature a helping hand !!"

Hi Christine,

The problem is always one of matching the right size pumps/filter for the size of pond. Unfortunately I think that the Hozelock Cyprios really are not man enough for the job, and their design is probably more suited to decorative feature ponds rather than ones that have fish in, because they block up far too quickly/easily.

I think part of the problem is that because they are pressurised units with no settling area for fish waste, debris and weed to "settle out" to a drainage point, all that muck just becomes compressed in the foam filters, to the point where they almost feel "solid" when you squeeze them out!

The idea of the bio-balls in the bottom of the filter is to provide high surface area for the bacteria to develop on. I think that if you put scrubbies (green kitchen scouring pads) in the bottom of your Cyprio (which is essentially a sealed unit) you will just end up giving the filter even more material to clog, and for you to clean.

Probably more important to help your pond mature faster is to give regular fresh doses of bacteria. I use both a solution type for "injecting" into my bio-filter, and a granular type for spreading in the main pond.

See my page http://leisure.prior-it.co.uk/pond-biofilter-bacteria.shtml for details of bacteria.

I wonder how many and which type of fish you have? During early pond maturation stage you should just have smaller, hardy types of fish, goldfish, shubunkins, to help build a mild ammonia level for the bacteria and bio-filter to start building up the nitrification cycle. It is only later when the pond has an established eco-cycle that you should put larger fish (more susceptible to disease and less tolerant of ammonia) such as koi.

Really your Cyprio will probably perform the job it needs to do, as long as you keep cleaning it out, but my feeling certainly with the smaller models of the Cyprio is that because they clog so quickly, and you have to clean it out every couple of days, then you are constantly disturbing the bacteria trying to develop inside it, and so this type of bio-filter really only ever acts as a mechanical filter, and I believe doesn't deserve to be called a "bio" filter.

As mentioned above a settling tank or section within the filter setup plays a major factor in helping remove solids waste, and letting the scrubbies in my own filter design do their work without becoming so clogged. Yes - the scrubbies do become filthy over time, but it is extremely fine sediment, which the bacteria is working on and turning back into minerals.

Also consider increasing the number of large plants in your pond, and also you might think about a "veggy" filter as part of a waterfall. A veggy filter acts both as a mechanical filter with its fine root system, and as a bio-filter where bacteria can feed on the fish waste and ammonia, turning it into nitrates which the plants in the veggy filter can then gobble up as fertiliser. In my pond I have plants in the top of my bio-filter, more scrubbies and cress inside the decorative water urn at the top of my waterfall, and then a bog area in the lower section of the stream. You probably don't have a stream, all I'm saying is that each of these features helps aid the growth of even more bacteria and plants, so I'm maximising mother nature to the full!

Do you have some kind of pre-filter cage on the pump in your pond? Something there could help to reduce the amount of muck going directly into the Cyprio.

Overall I think its the sum of many things which help keep a pond healthy and clean and bright.

Jim