I am doing a planted tank that is 1500x700x700.

My question is what will be the best light set up for growing plants? I want to work it out before I go and spend XX on some lights just to find out I messed up and need to spend more on some new ones.

What's your budget and what type of plants do you want to grow, they're the two factors that determine what you need pretty much.

Also for a tank 700 deep you pretty much have to use metal halide to be able to successfully grow anything that's considered light demanding.

As with all things the budget is as little as possible for as much as possible. always willing to fork out for something if it is worth it.

As for the plants, they will be mainly medium to high light required plants.

My main issue is tank depth, to type of lighting, have had suggested by a couple of people 4 T8's and others say MH.MH is what I originaly was thinking due to the tank depth, but just want to know other options before I got and do it

You probably don't want to use T8 lights, unless your plants are happy with a lower light. (for a planted tank you would normally use T5HO lights).

MH or LED is going to be the safest option. Unfortunately if you are trying to do this on a budget with such a deep tank it's going to be a real challenge.

One trick though - if you really cannot afford big lights - is to only half or 2 thirds fill the tank until the plants mature. Light travels just fine through air, it's when it hits the water that the trouble starts.

One trick though - if you really cannot afford big lights - is to only half or 2 thirds fill the tank until the plants mature. Light travels just fine through air, it's when it hits the water that the trouble starts.

Thanks for that tip, I have never thought of that. I am one of those people that fill a tank to the top so I havent thought about part filling before.