Gordo33

I have a 125 gal low tech set up. Substrate is BDBS. AMMONIA 0, Nitrites 0, Nitrates 20ppm(post WC goes up to 40ppm after one week) dKH 4, dGH 14. Temp 78-80 degrees. DIY sump filtration. I have pothos plant growing on top of the tank to assist with Nitrates
Fish stock 12 rainbows, 3 angles, 4 tetras, 2 bristlenose plecos , 3 roseline Denison barbs
Lighting is Fluval LED

I do not add ferts but by the looks of the plants they need some nutrients!!
Can someone identify the deficiencies and advise what ferts to add?

Attached Thumbnails

   

mistergreen

What's your GH?
If it's soft water, you'll need to raise your gH, that's calcium & magnesium.

Gordo33

dGH is 14

mistergreen

Hmm, hard to say. Might be overall lack of carbon or phosphate. Anubias are slow grower, don’t need that much light. If the lights are too strong, you drive it to want more carbon and nutrients.
How often does your anubias send out new leaves?

Gordo33

I’m note sure. In all honesty I haven’t been paying close attention . With this tank it’s been more about the fish and I threw in the easy growing plants with minimal care for aesthetics. They have been in the tank for several years and I have noticed they just don’t look as good.

davemonkey

I would try the basics first (Flourish or whatever other brand of basic plant foods are available at your local fish/pet store). I say this because you mentioned they've been in there years and have survived, but now look not-so-great. If they are well-rooted, maybe just some root tabs to start.
(This all assumes that your lighting is not intense...that it's low-moderate.)