I am addicted and plan to not limit myself on the type of coral i can keep
It's a great addiction
, but...
Try to keep in mind that your equipment generally neither limits nor dictates what corals or fish you keep. It's your knowledge that does that.
Don't get caught up in (too many) fads! And don't think you can over stock your tank without problems.
Go slow.
Learn - get to know - each and every critter you add to your tank.
Know everything you can about your critters in the wild, as well as what people have done in the past to keep them successfully in the aquarium.
Make mistakes early, before you've added all your live stock.
Making mistakes is human.
Making mistakes is how we learn.
So go slow, and let yourself be human.
Oh, I wouldn't do heaters in that manner. Too big, wrong design. Put one correctly-sized heater in each tank on the system. If you really want two (e.g. one is too long) then still use the correct total wattage. A 500-watt heater stuck on in a small tank will be a bad outcome in a big hurry.
Remember: Two to four times your display tank's size is all you need for return flow. 75 gallons x2 = 150 GPH x4 = 300 GPH. Much more than 375 GPH is pretty much a waste of pump and electricity....you should get your flow from power heads in the tank. The return pump just feeds the filters....and 2x to 4x is more than enough.... 5x (375 gph) would be the most I'd overbuild to.
Also, get a [HASHTAG]#lux[/HASHTAG] [HASHTAG]#meter[/HASHTAG] ($15 delivered) to help you set up whatever lights you get. (Run a search for "lux" on the forum, or click those tags, to see lots of past conversations about doing this.)
One gyre would be more than enough for a 4ft tank.
I would almost never recommend one pump for flow*, I don't care what style of pump or what the numbers on the box say.
At least two pumps (as the
@Nickh517 spec'd) to give a rough tidal simulation - strong, laminar currents in one direction for a few hours, then then other direction for a few hours. (Don't think that's news....just sayin it!
)
But there can definitely be uses for more than two good pumps in the tank!
There are oodles of combinations for a 75 gallon, but let's take your budget for
two Gyre's ($538 or $478 depending on the model
) and see what can be done within those bounds to create a "full service reef" that will support great coral health:
- on the minimal side, four Tunze 6045's on simple timers to create the tidal effect would be awesome - $312
- a pair of 6055's ($370) plus one or two smaller support pumps, if/when needed...you could add a 6040 or a third 6055 for around the same budget as the Gyres.
- three 6040's would make a pretty nice flow! ($420)
- a pair fo 6105's ($570) is even more overkill than the a pair of Gyre's, but they are strong enough to run any tank you'll have in the next two upgrades. (Thanks to that you will run them at a low percentage, causing less wear and tear over time, making them longer-lasting.)
Listing equipment combos is fun 
but honestly, what is ideal ultimately depends a great deal on what you do with the rock and later what the corals and other critters do to fill up tank.
Flow requires open space.
You
will need more than one or two sources of flow as the tank grows in as there will eventually be too many dead zones and too much space-restriction for large pumps to work as effectively as when the tank was empty. (In contrast, you may or may not eventually need more flow by the numbers...dividing the flow among more pumps is usually the ticket.)
Most people experience tank crashes or other problems before they get to that point, but it's a good thing to at least be aware of at the beginning.
* I don't know Jimbo662's scenario, so I'm not judging, just making an example.
