I have a 450g that I am about to switch over (from saltwater) to a planted discus tank. It was a reef prior to this, but about 3 years ago the front glass panel came off and everything died. I got a new tank in the mean time, but just didn't have the energy to get it back going again as a reef. Here is a picture of the old reef:
I did have a successful planted tank about 10-12 years ago, so I do understand the basics, but it was only a 110g and used a canister filter... my current system is going to add some complexities that I want to make sure I'm not running into an unmanageable nightmare! So please provide as much large-tank advice as possible.
Dimensions: 8'x3'x2.5' (LWH)
Overflow: double calfo (on each side)
Sump: ~120g, 4 compartment
Return pumps: 2x Dart Pump (output can be reduced as necessary), each ~3200gph +/- 400, I don't recall exactly
I will have large pieces of driftwood and some stacked dragon rock.
(1) Substrate: what type/brand/etc, and how many inches is recommended?
(2) Lighting: I currently have 4 250w MH's from my reef days, and 4x 39w T5s, and 1x 8 foot VHO (forgot the wattage, 160 maybe); Is any of this recommended to be used for a planted tank, or should I strongly consider switching out for some LEDs. Please swamp me with recommendations on lighting.
(3) CO2: I understand it will be a challenge to keep co2 up given the sump situation. But, what will it take for me accomplish this? I am sure technology has improved in the last decade...?
(4) Plant food: What is the go-to these days for dosing into the aquarium to keep the plants happy?
(5) Water changes: Discus require a great deal of water changes but am I really going to need to do these "25-50% weekly" ones with plants doing a lot of the water cleansing? I have an auto water change setup already, so I can do however much per day is recommended, but wondering what I should really expect on a weekly/monthly basis.
(6) Water additives: I will be using RO/DI water (0 TDS) as my initial water and then adding back what is needed. What is the go-to these days for this? Considering Discus here in the answer. And obviously to keep the plants happy.
(7) Algae prevention: Please flood me with recommendations on how to prevent algae from ever being an issue from the get-go!
Anything else is much appreciated! Let's get my tank off to a great start!