Seeding the filter

Previously, I did a fishless cycle on this tank which took a grand total of one month. This time, I switched from the Powerbio 700 by Classica to a Elite Mini (a tiny internal filter which is quite efficient and was a favourite of mine for my fish room) which I “seeded” with cycled filter media from my display tank. I had also switched the heater from the 50 W heater that came with the tank to a Visitherm 50 W heater which was also salvaged from when I broke down by fish room five years ago. This puts the heater and the filter both at around 7-9 years old and still in perfect working order.

To seed a new filter, some of the new filter media needs to be replaced with old, cycled filter media which already has all the necessary bacteria living on it. It is possible for a filter to be partially seeded, to kick start the cycle with household ammonia or for low stocking, or to be fully seeding so that it will be able to take closer to full stock immediately. If you are seeing your filter and aiming for higher stocking, I recommend that the seeding is followed by a fishless cycle, which should take no more than a week or so.

I drip acclimatised the fish as normal and set up the filter at the same time on the 13th of December. Ammonia and nitrite have been at a constant 0 ppm since then, which means that seeding followed by immediate low stocking works well.

Interpet PF Mini

I have just bought a couple of Interpet PF Mini filters for some small tanks to grow our fry. I have previously used Hagen Elite Mini internal filters for this as they retailed for under £10 each and were very low powered, but they appear to no longer be produced. The PF Mini has a recommended selling price of £15.99.



This is the bit that always gets me: most manufacturers do not list the dimensions of the filter, so I’m going to go ahead and fix this here. It’s 140 mm tall, 60 mm front to back and 43 mm wide. With the mounting bracket on, it is around 65 mm front to back and with the addition of the outlet nozzle, it comes to a hefty 100 mm front to back. The power cable is around 130 cm long.

Power and ratings

It’s a 5W heater, which costs £8.76 to run for a year, assuming that one pays 20p per kWh. Interpet claims that the flow rate is 200 lph, but do not specify if this is with or without filter media, and that it is suitable for tanks up to 35 cm long which are 5-40 litres in volume. It is rather good of them to market filters specifically for shrimp and growing on tanks, but it does make me wonder if this encourages some people to keep fish in tanks that are too small…

Filter media and capacity

The filter takes approximately 110 ml of media and comes with two rough “wool” sponges, a carbon sponge and a fine “wool” sponge. I plan to run this filter lined with fine filter wool and filled with porous ceramic media as I find those easier to clean and they are already cycled.


As with most filters, this one comes with an instructions booklet. This “most advanced and comprehensive filter available today” from “UK’s leading aquatic equipment specialist” comes without any references for those statements. To be honest, I don’t see how a basic internal filter can be considered “advanced” when we have self-cleaning, programmable filters available from Eheim.

Having said that, the explanation about the nitrogen cycle is pretty good and the advice about replacing filter pads is spot on at “never replace over 50% of the filter media at a time”. They even recommend liquid or tablet test kits to monitor water quality and specify that tap water will kill filter bacteria. The only improvement here could be to recommend 20-25% weekly water changes for the “average” (read, “overstocked and unplanted”) aquarium instead of 10% every 1-2 weeks.

Replacement parts

As the Interpet website does not currently have the booklets available online, here is a list of spare parts that are available for this filter:

  • Flow deflector: 2180
  • Impeller and housing: 2181
  • Mounting bracket: 2184
  • 3× suction cups (sucker set for bracket): 2183
  • Media housing (filter body): 2182
  • Rough wool foams: 2230
  • Carbon foams: 2231

A sad end to the project

On 1st of January 2012, this tank was moved from Berlin, Germany to UK. The move took around 48 hours and was successful, with a 100% survival rate of fish, plants and equipment. Unfortunately, I have since not had enough time to dedicate to appropriate research for the new posts, so the blog was put on hold.

Last month, this project met a rather abrupt and an unexpected end: I was away from a couple of weeks in the US, and during that time, without my knowledge, the filter was unplugged. On my return, I found no sign of vertebrate life in the tank. This has happened even though the people who were in the house while I was away knew the importance of a running filter.

You can view all the posts relating to this aquarium in the 60 litre aquarium category. The posts of most interest to beginners are the following:

The three items that are highlighted are the ones that I have referred others to most often, as they are usually the most misunderstood and clouded in myth.

This is the last tank shot of the aquarium:

Before trimming

Of course, this is not the end for the tank and I will soon be setting it up again. I do not have much preference for set-up, other than it be a biotope, so I welcome all suggestions in the comments! Anything from a detailed set-up to a species that the rest of the tank should be created around would be considered.

Next time, I plan to explain how to seed a filter from an existing tank, and whatever else is requested. In the mean time, I am using it to grow plants that fund my hobby.

Daily tests: day 48 – 57 and adding wood

Test tubes waiting to be washed

I’m planning to do a large water change tonight, in preparation for the fish, and I would also like some clear readings for the record, so I know how much the wood will affect the water after it is added. This morning, the readings were:

  • KH: 9.5 ° (170 ppm)
  • GH: 21 (376 ppm)
  • ammonia: 0 ppm
  • nitrite: 0 ppm
  • nitrate: 80 – 160 ppm
  • pH: 8.2

I expect KH, GH and nitrate to drop after the water change because my tap water readings are lower.

Unfortunately, the diatoms are still there and getting worse, so hopefully, the water change will help improve the situation. I also have a Malawi aquarium, which, for those of you who do not know, is a Lake Malawi simulation, with a lot of rockwork and no plants because the fish which live in the lake naturally graze on algae and have a habit of mistaking plants for algae, which means that most plants would not survive for long. In this rocky and plant-free environment, I also often see diatoms, and as is currently the case with this aquarium, the Malawi setup also has high nitrates, so I assume, given that the general hardness is the only other common factor between the two aquariums, that the nitrate is responsible. I have also noted the appearance of cyanobacteria, an algae-like bacteria, today. I hope this is also related to the high nitrate levels.

I performed a clean of the aquarium, including glass and filter, and changed 36 litres of water, which was approximately 80%. The water readings after the maintenance were:

  • KH: 10.5 ° (188 ppm)
  • GH: 18 (322 ppm)
  • ammonia: 0.25 ppm
  • nitrite: 0 ppm
  • nitrate: 10 – 30 ppm
  • pH: 7.8

The results indicate that my tap water has changed since I took the original readings: my tap water pH has dropped, while the KH has risen.

I also added the wood, right after the water changes. It has now picked up the rich red which gives it the name of “red moor wood”, but is being slow to water log.

Daily tests: day 31

This morning’s test results were:

  • ammonia: 0 ppm
  • nitrite: 0 ppm

Some of the plants are starting to suffer from the higher temperatures and no light. Given that my first stock will be 9 × 10 mm Danio margaritatus, I expect that they will not produce more than 2 ppm of ammonia per day. So, while for a full stock I would be aiming to see 4-5 ppm of ammonia processed in 12 hours, I will settle for the 2 ppm in 24 hours for now. I will now gradually start dropping the temperature into the 22 °C range and I will start using the lighting. To avoid algae problems, I will also dose ammonia in the evenings from now, instead of the mornings, so that by the time the lights come on, there will not be much ammonia left left.

Daily tests: day 27

I have been very busy with the Desktop Summit recently, so I haven not really had that much time to write anything interesting lately and this is also why I missed the reading yesterday, in my hurry to get in for my volunteering shift. Because I keep getting consistent readings, I added about 0.5-0.6 ml of ammonia, to keep the bacteria going until today. This morning’s test results were:

  • ammonia: 0 ppm
  • nitrite: 0 ppm

So currently, the bacteria are processing 1 ppm ammonia and about 3 ppm nitrite. Because I read a double 0 reading this morning, I decided to increase the ammonia dose to 1.5 ppm, which should result in 4 ppm of nitrite. So, I added 0.75 ml of ammonia to the water and the resulting reading was:

  • ammonia: 1.0 – 2.0 ppm