. How many of those do I need? (yes I'm dead end broke lol.this would be awesome if I only need one)does it need a ballast?
Thx
You could probably get by with one. No ballast, but you do need some type of clip on fixture to hold it in position.
Can't I just hook up 4 10watt LEDs withs a 40 watt ballast?
No. For any LEDs you need a driver, not a ballast, that is matched to the forward voltage of your LED circuit, and can supply the correct drive current to the LEDs. You also need a heat sink, fans, soldering iron, and misc. other supplies to put the light together. 4 quality 10W LEDs and a driver, or driver power supply combo would likely be more than the RapidLED kits I posted originally.
Again, there are ways to save money, but this is an
expensive hobby! This is just my rule, but I rarely purchase a piece of equipment without thinking whether or not it becomes obsolete the first time I upgrade my tank. For example, the RapidLED kit I posted can be expanded upon, and even integrated into as big a system as you may eventually want. You seem to be solely focused on building a 10 gallon tank with components that likely won't transfer to a 50 gallon tank when you want to expand. This money will be wasted, gone because there is no resale value on basic equipment.
The most pragmatic advice I can give to you is this: If you can't afford a quality light, and other equipment right now put the halts to this project ASAP. Take some time, and save some money until you can do it right. If you can't afford a light up front how will your animals be able to handle it if a marginal piece of equipment, like a cheap light fails and you don't have money to purchase another? Once this tank is up and running your expenses have only begun. I would say stop, take a
DEEP breath, and rethink your plans. Not only will you be disappointed when the shoestring budget tank fails, but it's unethical to subject living creatures to a marginal system that is likely to fail.