Old tank New to Freshwater

[Grumpypawpaw]

Hey Guys,
I have had a Saltwater reef setup for 10-15 yrs and it crashed a few years back and I lost everything. I cleaned the tank out and it has been sitting every since. My vision is to setup and maintain a Freshwater Planted community tank. What I have is a 75 gal tank with a built in overflow that drains down into a 15 gal tank with a return pump. It has a LED light system that I can control the color and intensity and 2 power heads that I can control output on them also.
I am looking for some suggestions on if I need to change anything out or add something. I am looking for suggestions on Substrate, fertilizer pellets that go under the substrate. Do I need a water filter system or will dechorionize be good enough for the water?

Thanks in advance for any help.

 

[nate77]

The 1st thing I would do if the tank has been sitting for a few years, I would fill it with water some you don't care that gets wet and do a leak check.

 

[Grumpypawpaw]

Ok, tanks has been up and running for 3 days no with a freshwater and Vinegar mix to help clean the tank and sump. No leaks
I have a Current USA Reef light system that I can control the Red, Blue, Green, and White intensity. Here are pics of the Tank with lights on and all colors at 100%, return pump, and 15 gal return tank. Please keep in mind this is still in the cleaning and testing for leaks stage.
Should these lights provide what is needed for a Freshwater Planted Community Tank? I do have a Heater and filter socks for the lower tank. The powerheads in the tank are not on at this time and I don't think will be needed for a Freshwater tank.
Are most people using tap water dosing with decolorizer or using a 3-4 stage water filter??

All Suggestions and thoughts are appreciated.

Thanks,
Ron