The bulk of the maintenance that has been happening on this tank since October has involved topping up the evaporated water, filter cleaning, manually removing algae and water changes.


One of the issues that the family which has the tank had was that topping up the tank with a bucket disturbed the substrate. I generally avoid the problem by balancing the bucket of new water on top of the tank and syphoning it in. This helps avoid spilling water all over the place and the water from the water butts tends to be freezing this time of year so I’m sure the fish appreciate not having a shock of cold water. Their solution is to place a mug in the tank and pour the water over that (similar to the plate suggestion that seems to be popular in books).

In the mean time, the die back from the plants kept clogging the filter, which they started cleaning in old tank water, but then replaced the filter media altogether. Luckily this was before the fish were added, but I have reiterated the importance of not replacing the filter media in one go.

Fish - 3

The algae that was removed in the previous maintenance session has not come back after the lighting was reduced and the Spirodela spp. was introduced. They haven’t used the EasyCarbo, but I have now advised a dose of 0.25 ml per day to encourage plant growth as nitrates were high in the test results:

  • ammonia: 0 ppm
  • nitrite: 0 ppm
  • nitrate 50-80 ppm

The predominance of tap water top ups (we live in a hard water area) has caused the water in the tank to be quite hard, but this is likely to be beneficial to the plants in the long terms. At last water change yesterday, we removed 5 litres of water and added 20 litres.

I have trimmed the Limnophila sessiliflora a few times and removed over twice as much Spirodela spp. as I had originally added to the tank. The Cryptocoryne wendtii ‘Tropica’ has shown good growth as well, although Crypt. sp. ‘Green Crisped Leaf’ has remained the same size but now has submersed leaf growth. I added four sera Floronette A root tabs, one under each of the Crypt. spp. and two spaced equally under the other plants.

We also got a dark-blue on the bottom to blue on the top background for the tank and replaced the perspex lid with a glass one which is available for a shocking £20 from Arcadia. It works very well, but really should have come with the aquarium from the start. The glass lid is satisfyingly solid and easier to clean with vinegar than the perspex one.

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

First shopping list – the details

Following on from the first shopping list, here are the explanations for why the items on the first shopping list are needed and what to look out for.

  • Aquarium

    The best aquaria for beginners are long, rectangular ones as most beginners do not know which way the hobby will take them and these are the tanks which give the most stocking options. It is best to go for at least a 90×30×30 cm (3×1×1 ft) tank as anything shorter will restrict you even on many of the “popular” fish. 60×30×30 cm (2×1×1 ft) is the absolute smallest that I can recommend to any beginner as setups smaller than that will not tolerate mistakes. Taller aquaria will not allow you to keep any larger fish, nor (really) any more fish, but the extra water will result in more stable parameters. Tank height does matter for some fish, such as Pterophyllum spp. (angels) and Symphysodon spp. (discus), but they should have quite large tanks anyway (for most species starting from 150×60×60 cm (5×2×2 ft)), so are usually not kept by beginners. Tank width/depth (the front to back measurement) does not matter too much for tanks tanks under 120 cm (4 ft) as they are too small to keep any fish that are large enough to have trouble turning around in a standard 30 cm (1 ft) wide tank. Odd shaped tanks and ones with low surface areas should generally be avoided if one does not want an extra level of difficulty and more stocking restrictions, this includes cubes, hexagonal prisms, “picture frames”, bowls and tanks with artificially reduces areas such as the Fluval Edge.

  • Filter

    Usually, the filters that come with the aquarium kits are fine, but if you do not have one, then I recommend external filters. I prefer to use Fluval internal filters or Eheim external filters. If the filter has activated carbon inside it, then the activated carbon should be removed and replaced with a media that does not affect the water while providing a high surface area for bacteria, such as porous ceramic media or sponges.

  • Test kits for ammonia, nitrite, GH and KH (water hardness), nitrate and pH

    It is only worth spending one’s money on liquid test kits, or maybe digital ones, but the strips are usually very inaccurate and can give false positives and, more worryingly, false negatives.

  • Dechlorinator

    Your first dechlorinator should be one that claims to “deal” or “neutralise” chlorine, chloramine, ammonia and nitrite. These are usually about the same price as ones which only work on chlorine and chloramine and add an extra level of protection because one of the by-products of chloramine removal is ammonia, so if your water supply has chloramine, as many in Europe do, then using a more traditional dechlorinator would leave the new water with ammonia in it, which would make the water changes during cycling redundant. Also, tap water can contain both ammonia and nitrite, both of which are harmful to fish.

  • Household ammonia

    Any household ammonia that does not contain anything other than water will do. Apparently the test to see if it contains other things is to shake up the bottle and see if it produces foam: if it does not, then it is what you want, but if it does, then it contains other constituents. I have never tried this method as I have never seen ammonia that contains other cleaning agents or perfumes in it. In the UK it is possible to buy ammonia from Boots, in the USA from Ace Hardware and in Germany from eBay.

  • Tubing for water changes

    Anything that is clean will work, starting from filter tubing all the way to garden hoses. If you plan to refill the tank straight from the tap, then it is worth getting a short length of tubing and a longer one or a python system.

  • Bucket

    Useful for lugging around water and for acclimatising fish. The bucket needs to be a new one and must never be used for anything other than fishkeeping to avoid contamination and poisoning the fish.

  • Thermometer

    Alcohol and digital thermometers are the most accurate. Avoid liquid crystal thermometers as they measure the temperature of the room and glass, not the water.

  • Heater

    Almost any heater is fine, I prefer to use NeWatt heaters because they are ceramic, so are more difficult to break and are less likely to fail than a glass heater. A good heater should last you a very long time (my oldest working heater is probably around 15 years old), while a bad (normally cheap) heater can break very quickly (most of the “cheap” heaters that I have had have failed in under 5 years). If you use a glass heater, make sure you have a heater guard for it: this is a plastic cage that goes around the glass, preventing the fish from touching the hot heater and burning themselves. A heater guard will also reduce the risk of you or a large fish smashing the heater. As a very general rule of thumb, one should have approximately 1 watt of heater per litre in a well heated house. So for our 90×30×30 cm (3×1×1 ft) example tank, which is approximately 80 litres in volume, we need an 80 watt heater. Since most heaters come in 75 or 100 watts, I would chose the 75 watt heater if I knew that the room was always warm, or the 100 watt heater if I could not be sure that the room is always heated. Another option would be 2× 50 watt heaters.

  • Substrate

    Research the substrates and go for your final choice right from the start. I recommend sand from a garden centre because it is usually no different from aquarium sand, but is considerably cheaper, and allows for a much wider selection of stock.

  • Plain background

    I prefer black, but dark blue also works well. White is more difficult to pull off, and the printed backgrounds usually look just tacky. At the very least, a background will hide the equipment cables, and it can even make fish more bold.

Next time, I will be writing a post-cycle shopping list.

Danios settling in

Danios are in

It has been almost a week since the Danios were added, they have settled in well and are relatively bold, but do not seem to appreciate when someone walks quickly across the room (as is expected). They certainly seem to enjoy the piece of wood, spending much of their time swimming through the holes in the base and around the stems, but do come right to the front of the glass when they notice me looking at them. The females are receiving plenty of attention from the males and one is looking considerably more plump now, so they may spawn soon.

The fish found the flow of the filter to be disturbing, so I have attempted to slow it down by wrapping filter wool around the rough sponge and placing more still between the sponge and the bio media. It seems to have helped slightly, but not enough, so I am still thinking about how to slow it down further. The stand building project has come to a bit of a stand still as I am quite lazy, but this has given me an incentive to get it going again because the external filter has a 300 lph rating compared to the 700 lph that came with the aquarium.

The fish are feeding well on frozen Daphnia and Artemia, with a supplement of high-protein granules and generic flakes. The 10 fish eat only tiny amounts, so even the smallest tub of fish food will last for years at this rate. Given that most fish food goes off in a matter of 1-6 months, it makes sense to separate it into smaller containers, freezing or chilling the majority of it until it is needed.

There have not really been any major signs of algae, I am still cleaning off mild signs of diatoms from the glass every couple of weeks, but that is it. Most of the plants are doing well, and I plan to split up one or two of the Cryptocoryne parva bunches into individual plants over the next week.

Filter media

Filter media

Before I added the filter to the aquarium, I removed the activated carbon and replaced it with some porous ceramic media.

I used Substrat Pro by Eheim as the space available was quite small at approximately 6 by 3 by 3 cm and Substrat packs more densely than porous ceramic “noodles” would. I do use a number of different types of ceramic media in my larger filters and can not say that one is any better than the other. There is one point to watch out for when buying ceramic media and that is that some media is not porous: this type of ceramic media is actually intended for spreading the flow of water in external filters before it reaches the porous bio-media, not as purely biological filtration.

The carbon I have removed is now put aside, into a dark, cool storage space, until I will need it to remove the remainders of medication which was used in the aquarium. Even though I do not expect to have problems with the fish, I still keep medication for occasions when a couple of fish may have a pecking order dispute or one may scratch itself on a piece of decor. These are rare occurrences, but impossible to prevent.

There is little sense in using chemical media such as carbon or zeolite on a regular basis because these will mask problems in aquaria and can affect the effectiveness of the filter. I even go so far as to not use any chemical media except carbon, and that only on very rare occasions and only because manufacturers seem to insist on including it with every new filter that I buy. I believe that carbon will be used up in anywhere from few hours up to a few days after being added, and there is consensus between many fishkeepers that at most it would last one week. When it is used, carbon is most effective if the water is filtered through it at a slow rate, which is relatively unusual for an aquarium filter as most fishkeepers aim to have the highest flow rate filter possible.

My preferred filter configuration for most aquaria is rough sponge pre-filter, leading to bio-media and finally passing through a filter wool polishing filter. In this setup, the rough sponge should filter out large pieces of solid waste, the bio-media will deal with ammonia and nitrite, and the filter wool (which is also known as filter floss) will “polish” the water, removing any remaining solid waste. The Powerbio is a two compartment filter: the media housing has a large, rough sponge which is accessible through the bottom and a separate, plastic compartment which is accessible through the top of the media housing. I may add a layer of filter wool later on, but for now, I have settled on the rough sponge with the bio-media.

The filter

Filters are essential to modern fish keeping: they are home to bacteria which make the water safe for the fish.

The nitrogen cycle in an aquarium commences at the point where fish and dead plant matter produce ammonia. Some of the ammonia is then used up by plants, but the majority is converted, by bacteria which live in the filter, into nitrite. Nitrite is then converted by filter bacteria into nitrate. Some nitrate is used up by plants and the rest is removed during water changes.

The general format of a filter is some sort of pump which causes water to move through some media. This is usually in the form of an internal filter, an external filter, an air pump powered sponge filter, an undergravel filter, a sump, a trickle filter, a hang-on-the-back filter, and so on. For this aquarium, I will be using an internal filter, potentially moving onto an external later on.

There are three types of media usually used in filter:

Mechanical media:
This media includes various sponges, wool and floss, it physically removes dirt from the aquarium by not letting it pass through the filter.
Chemical media:
The primary function of this media is to adsorb undesirable certain molecules out of the water: for example, activated carbon can be used to remove the remainder of medication after a completed treatment. Some “chemical media” works on the basis of ion exchange. It should usually not be used on an every day basis.
Biological media:
Bio-media is the best media for the bacteria to live on because it is usually very porous, so has a high surface area. It is usually made out of some sort of ceramic material. In an undergravel filter, the bio-media is the gravel and in a sponge filter, it is the sponge.

The bacteria are not particularly picky, so will actually live on any surface they can, regardless of the type of media used.

The first step for setting up the aquarium will be cultivating these filter bacteria. They are present in tap water in very small numbers, so I will be feeding them ammonia to encourage the colony to grow. Once the colony is large enough to support fish life, I will be replacing the ammonia with fish (who naturally produce ammonia).


The filter which came with the kit is a Powerbio 700 by Classica (which is the Arcadia brand for non-lighting equipment). It consists of a standard filter power head with a screw-on spray bar attachment, on top of a filter media housing which contains a cage for loose media (containing carbon) and a rough black sponge (not carbon). The carbon has already been taken out and I will be replacing it with some form of bio-media. I will keep the carbon in case I ever need to remove medication after treatments.

Weekly maintenance and a manufacturing defect in the Eheim filter

So today is a “large” water change day, with a 10-15% water change. I was planning to clean the filter (Eheim 2076) as well, but I have found that there is the same problem with this one that I had with one at work last week: the “floater complete” (part number 7428728) can become dislodged during re-assembly, after cleaning, which allows the middle part of the three which make up “floater complete” to move up into the “adaptor complete” (aka the tap for the hoses, part number 7428718), which means that it is becomes impossible to turn off the tap because the little white tube blocks the part where it closes off. Who comes up with these part names? The symptoms of the problem are inability to close the tap (feels like it is stuck) and if you push it a bit too hard, the tap will easily move from “on” to “off” and back, but without any effect (while making clicky noises in one direction- yes, you have snapped it). The solution is either to take the whole pump to an Eheim repair centre (if it is under warranty, it took them 24 hours to fix, they also did a 6 hour service on it and flashed the firmware, while they were at it) or use a Torx T9 screwdriver to pull apart the filter and fix it yourself (which will probably void any warranty you may have).

If you attempt to fix it yourself, you will get water everywhere, so be careful with the power sockets which your filter is probably plugged into and which are right next to it, on the ground. You will need to lift the inlet and outlet tubes out of the tank, then drain them by undoing the clips, separating the pump assembly from the canister and letting the water drain over the sides onto strategically placed towels. Next step is to pull the pump assembly apart and remove the offending part, reassembly should be quite easy. Photos to follow when I actually go through with this!

Why manufacturing defect? Because this has happened on both of my 2076 filters, within a week of each other. Yes, I am quite careful about reassembling everything properly. Luckily, the filters only need cleaning once every few months, so it’s usually fine to take one’s time over getting it fixed.

It is still an excellent filter, even with this flaw.. but it is an important flaw to be aware of, so one does not break it accidentally.

Oh yes, and lighting is now on from 11:00 until 21:00.