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.

Hitting the first problems and finiding solutions

By mid-November, the newly set up, fish-free tank already showed some problems, the biggest being the appearance of fluffy clouds of dark green algae along the surface of the substrate. To counteract this, I suggested reducing the lighting period (which had been set to around 12 hours by the family) to 10 hours. I also gave them some Spirodela spp. which is a type of giant duckweed that can have a nice red tinge and a bottle of EasyCarbo, a liquid carbon fertiliser which also acts as an algaecide. We then manually removed as much algae as possible while doing a water change and left it at that. I also gave them some sera Florenette A root tabs (which are best value for money), two of which were inserted into the substrate at the time.

In that 6 or so weeks, some of the plants settled in nicely and some died off. Mainly, the Limnophila sessiliflora tried to take over the tank, while the Bacopa lanigera, Lindernia rotundifolia and Lysimachia nummularia ‘Aurea’ died back heavily. This corresponds with my experience that without investigation and special attention, some plants just take to some tanks while some just don’t.


The other problem that the family encountered is high levels of evaporation as can be seen in the photo below. With the tank temperature set to 24°C, this was unexpectedly high as I get considerably less evaporation in my “hot” tanks. The problem with topping up is that it increases the water hardness in the tank, and disturbs the substrate, but this was resolved later.

In the mean time, I had failed to find my background for this tank, so it was looking a bit bare without one. The sagging lid was also irritating everyone.


Restarting the 60 litre project

Following a rather unfortunate end to the 60 litre project, I have now re-set it up at a friend’s house for their 5 and 6 year old children. The parents have the previous white-ups from this project for reference, and my advice, in person, on demand. Their life style is relatively busy, with little free time, so we’ll see how a fish tank fits into their schedule.

We set up the tank with the 5th of October. I wanted to use Moler clay for the substrate because it resembles the popular gravel more closely than sand would. It should also keep a higher bank at the back more easily. Moler clay is a ridiculously dusty substrate which is sold by some aquatics suppliers, but is also available for the bonsai tree hobby as a substrate for the plants, as cat litter (which may be fragrant) and in some other industries as well. Moler clay, which is calcinated clay consisting mostly of diatomaceous earth from Denmark, supposedly has a high cation exchange capacity. In simple terms, this means that it will extract some nutrients from the water column and make them available to the plants through their roots instead.

I was reminiscing about one of my first tropical aquaria around this time, which was set up in the early 2000s. I was using Dorset pea gravel at the time and as it sat in the corner of the room, I created two tiers: a 1 cm layer of gravel at the front and a 10 cm tier across the corner which was propped up by oak branches and had a “cave” from a plastic pot that was cut in half. As this tank will be viewed mainly from the front (from the dining room, across the lounge) and the right side (from the sofa in the lounge), I decided to try for a taller tier at the back-left of the tank sloping downwards to the front-right and only a little substrate at the front. I’m hoping this will allow the higher tier to be planted heavily, while keeping the front clear for viewing and feeding. I was recently lucky enough to acquire some dragon stone at a good price from another hobbyist, and wanting to involve the children, I let them pick out a few pieces for the new tank. These now line the tank about a third of the way to the back, and from the left side to three quarters across the tank.

Next came the plants. The children, stayed relatively engaged while washing the substrate as they enjoyed plating with the hose and getting soaked (in October?!?). Guiding their dragon stone placement strategically was a bit more challenging. Filling the tank with water was slow torture. They did redeem themselves on unpacking and sorting the plants by species.

2 pots of Bacopa lanigera went into the back-left corner, next to the filter, thermometer and heater. Two pots of Lysimachia nummularia ‘Aurea’ went in front of the Bacopa. To the right of the Bacopa, one pot of Limnophila sessiliflora and next to that the Cryptocoryne wendtii ‘Tropica’. Two pots of Lindernia rotundifolia went in between the Crypt and the right side of the tank. The Cryptocoryne sp. ‘Green Crisped Leaf’ took the spot on the right side of the tank, on the substrate slope between the front and the back.

60-litre-1I left them with a bucket, piece of hose, net, dechlorinator and a full test kit (ammonia, nitrite, nitrate, GH, KH and pH).

Large water changes

When raising young fish, it is a relatively good idea to occasionally do large water changes to remove waste products from the aquarium, but this is not the commonly given reason for the large water changes; the more common belief is that fish release growth stunting hormones/pheromones, but I have been unable to find any scientific proof to back it up. It is true that fish release a growth hormone (GH) which stimulates growth, but they can also become resistant to the hormone if they are already stunted, for example, because the competition for food is too high. There are also other factors that affect growth, including higher nitrate concentrations. Of course, any ammonia and nitrite[2][3] are very high on the list, but this should not be a worry as neither should be present in an aquarium.

Before starting on the water change, I check the water parameters. I know that my tap water is quite hard, and the results below show lower water hardness, lower pH and higher nitrates. This means that my tank water hardness has drifted downwards from my tap water and not all nitrates are being used up, which indicates that I need to refill the tank very slowly after the water change so that the fish have time to adjust to the change in water parameters and do not go into osmotic shock.

Parameters before the water change:

  • KH: 8 ° (143 ppm)
  • GH: 16 (286 ppm)
  • ammonia: 0 ppm
  • nitrite: 0 ppm
  • nitrate: 20 – 30 ppm
  • pH: 7.5

Water change

As can be seen in the photo, the tank is really rather overgrown with Pistia stratiotes (water lettuce), so I regularly have a bag or so of water lettuce to sell. If you would like some, reply to the post or contact me for more information!

[1] John Colt, Robert Ludwig, George Tchobanoglous, Joseph J. Cech Jr. (1981), “The effects of nitrite on the short-term growth and survival of channel catfish, Ictalurus punctatus”. Aquaculture , Volume 24: 111–122

[2] Jane Francesa, Geoff L Allana, Barbara F Nowak (1 April 1998), “The effects of nitrite on the short-term growth of silver perch (Bidyanus bidyanus)”. Aquaculture , Volume 163 (Issues 1–2): 63–72

Post-holiday update and maintenance

My friend came twice to check on the fish in the two weeks that I was on holiday and each time did a small water change, then fed the fish.

The hair algae has made a come back, while I was away, so I’ve had to pull out more of it. It is growing predominantly on the side of the aquarium where natural sunlight falls. I also gave the plants a trim and did a 15% water change. While I was on holiday, I managed to trade some Crypt. for water sprite and Riccia.

Water parameters are nitrate at 30 ppm and pH 7.4-7.6, I also tested for ammonia and nitrite, which I would normally not do in an established aquarium.. both were 0 ppm. Filter claims that it does not need cleaning, so it didn’t get any.

Weekly maintenance and update on plants

420 litre: Ludwigia removedThe Ludwiga brevipes has been growing fuller of hair algae and loosing its leaves, so I have pulled it out for the moment and am trying to perform a blackout on it, in the hope that the algae would die back before the plant.

During the more major weekly maintenance, I performed a 10% water change and tidied plants. Water readings were nitrate at 15 ppm, pH 7.4, 20 °GH, 3 °KH.