GrahamC

If I had two fish from the same tank get sick, I'd use a UV filter ... Some people have had issues with melafix leaving an oil on the water surface blocking o2 exchange.

What about a flued gas heater in the room??

Just curious... but how many tanks do you have, how many 50-300W heaters would you need if heating each tank individually? And what contingency plan do you have for a power failure in the middle of winter? My guess is that in tank heaters would be able to restore the heat to each tank much faster than by heating the entire room ...

Unfortunately the error is likely on the part of the OP. There are enough horror stories like this on the internet to know that this is a likely outcome no matter how detailed the instructions are. If you have to rely on a person to feed you need to do a training run first, or, give them a goldfish to look after for a week at their own home. And then check the water parameters after a week to see if they have coped. I did some training videos for my daughter when she had to look after my fish, and called daily to see how things were. And the very first day she asked me why the scales were falling off my Oranda &c:ry

The point of cycling your tank is to create the population of bacteria on the filters and other surfaces in your system. Once that happens, you can then replace most of that water with clean aged or dechlorinated water that you know is contaminants free. I guess you can't replace all of it as you will then starve the bacteria.

I've got several tropical tanks covered in duck weed and it's not been eaten. I remove it from time to time to feed the goldfish.

Stack this tank against the larger tank and heat the larger one? Get a smaller heater?

That sounds very inefficient. I suspect you would be better off heating the water directly than indirectly using air to water heat transfer.

There's a guy on youtube who is using Lucky Bamboo to remove nitrates from the tank. Also you can build a algae scrubber http://www.aquariumslife.com/saltwater-diy-projects/diy-algae-filter-screen/

Auckland temperature is 19.5C at present .. and you run your interior temperature at 38C? Or do you have a fever??

do you have a concrete slab on a north facing window? I got a SolaVenti 70 that I might put on the roof of my shed to dry the air, and add a little heat.

Since you want to encourage the growth of the bacteria that do the nitrite to nitrate conversion, I can't see how this would work. The idea of the 100% water change is to remove any contaminants in the original priming solution you used... AFAIR.

I couldn't get the primer on my sun sun working ..in the end I filled the cannister with water, put the lid on, and only then was the priming "button" able to start the siphon.

Acidification of the water ....

Ahh... you've got adolescent fish ... mine are already parents :slfg:

What's the point of the daily water change? My understanding is that you do a 75% ( or was it 100% ) water change once the tank is cycled. And then put the fish in.

It's just when I look at the fish, they seem to look back at me and I have the feeling they're asking me when I am I going to clean the tank for them :digH:

Looks like you're using tap water for the veggies ... I'm putting all the fresh water from my water changes onto all the house plants I can find!

I had a BN die the day after I bought him. He got himself into a horizontal drain and i think suffocated due to the lack of circulation. When I emptied the pipe, the contents were foul though the rest of the tank was clean as. So, I suspect dead areas in a tank can give a very different micro climate.

Impeller jam, or motor burn out ... dunno, but I am often away for a few days at a time and can't trust the kids to look after everything for me! :dunno:

One of the US sites I read suggests that you can easily outperform these external cannister filters with an internal powerhead filter attached to a fluidized sand filter ( US$69).

As far as I can tell you're suggesting that an undergravel filter but without the flow of an undergravel filter has more biofiltration capacity than your appropriately sized take your pick external filter?? The issue I see is that although you have a large surface area, it's not functional in that if you create sufficient flow, your fry will get battered and then fried! :slfg: http://www.americanaquariumproducts.com/Aquarium_Filtration.html

I guess I am doing this for partly foro insurance so that if the filter dies while I'm away, there isn't a large amount of waste that can potentially wipe out the whole population.

My take on this is that the bioload is so small in this situation that the biological filter on the substrate is able to cope. However, the biological filter is primarily in the filter media of what ever filter you use.

Well, clearly there is some difference of opinion here. So, my summary so far is that: In a planted tank ( not the situation here ), then fish waste is useful to leave around the roots as long as the ammonia levels are fine. In a tank where the plants are free floating, or the roots are not used to absorb nutrients, then it does not make sense. I worried too about too much visible waste being unattractive on a sandy bed, but I put some craft plastic sheeting against a side of the tank ( to hold some plants ), and I found that a lot of solid waste gets trapped at the base. So, it gets hidden behind it and I can easily lift it a cm or so to vacuum at the base.