Two questions from a noob!

[ian_m]

Will I likely need to supplement iron or phosphate or anything?

With low light levels and small numbers of low poo rate fish you can get away with no extra carbon or fertiliser source for the plants, as rotting fish poo will fertilise the plants, but is quite a slow rate in doing so.

In your case you will probably need to add small amounts for carbon source and fertiliser source in order to allow the plant growth to keep up with the goldfish destruction and eating rate. However in doses not as high as hi-tech dosing levels.

So if you are low tech (ie no CO2) and low light, dose a liquid carbon at say 1/4 rate in your 100l tank (2ml twice a week ?) and EI dosing solutions 5ml twice a week, alternate macro days to micro. Doesn't need to be exact amounts and times as all low tech and ticking slowly along. My mate has a low tech tank, doses liquid carbon once every couple of days and EI solution every couple of days and plants are growing nicely and algae free.

Suitable liquid carbon here...
http://www.aquaessentials.co.uk/neutro-co2-medium-p-6377.html

 

[ZeeDeveel]

A trove of knowledge here, thanks so much Ian, this is really useful.

Any word on how red/blue LEDs look in an aquarium? Will the purple drown out the colour of everything else?

 

[ian_m]

Any word on how red/blue LEDs look in an aquarium? Will the purple drown out the colour of everything else?

I think you will find without the green to reflect off green plants your planted tank will look "washed out". Look in the lighting section of this forum for how plants look under differing T5 tubes.

Plants don't really care about spectrum, they use what light there is (broadly) but your human eyes do. Choose lighting to make your green plants stand out to your eyes.

 

[ZeeDeveel]

I'm gonna go with 6500k or so I think. Purple will make everything look drab, you're right.

Would heavily insulating an unheated tank increase it's temperature by any significant amount? Would it help the tank maintain heat from the day overnight better?

I'm wanting to keep the tank from getting uber cold in winter. If I were to get a heater, what sort of running costs could I expect for keeping a heavily insulated, 300 litre tank at about 14 degrees during the winter? And what size heater should I get? (It'd be insulated with thermawrap on 5/6 sides.)

 

[parotet]

I bought once a pink tube, probably something similar to the grow tubes. If you just look inside the tank it is fine, the layout looks more red. The problem is when you notice that your living room looks like if an UFO had landed. Not nice, those tubes spread a weird pink glow.
I use T5HOs and now I buy the cheapest tube I can find in my hardware store between 4,500 and 9,000 Kelvin. Plants look nice and it looks more or less natural. I usually buy them for 4 to 6 euros (Osram, Phillips, Sylvania... 24w), good quality and very cheap compared to the aquarium-brand ones.

Jordi