Planted tank, no fish, least expensive way.
If you're going to want to have good growth with decent lighting, I'd rule the HOB out. Get a decent powerhead with a pre-filter sponge and you're set. If you find that you need more circulation, just get another powerhead and put it on the other side of the tank. =P Each powerhead can then be plumbed with a line supplying CO2 for a DIY venturi reactor. =)
A HOB will outgas lots of the CO2 you try to put into the tank, so it'll be somewhat counterproductive to what you're trying to achieve.
The best choice would be to get a canister filter, but it also wouldn't be the most economical.
If you're going to want to have good growth with decent lighting, I'd rule the HOB out. Get a decent powerhead with a pre-filter sponge and you're set. If you find that you need more circulation, just get another powerhead and put it on the other side of the tank. =P Each powerhead can then be plumbed with a line supplying CO2 for a DIY venturi reactor. =)
A HOB will outgas lots of the CO2 you try to put into the tank, so it'll be somewhat counterproductive to what you're trying to achieve.
The best choice would be to get a canister filter, but it also wouldn't be the most economical.
