Can I expect algae problems

Does seem like a lot of light for just Anubias, do you know what kind you have? The larger ones seem to grow at a faster pace.

What about some floating plants to diffuse the light? I have tons of mini water lettuce (was sold to me as frogbit, but definitely is not Amazon frogbit) I can mail you for real cheap if you'd like.

Water sprite doesn't like me, but another fine choice if you can find it.

You need ALOT of plants to fight the algae for nutrients. Get a sprite, they get big..and fast.

What are using the 20 for anyways??

wow that's a ton of light. I would reduce it down to maybe a 1/4 of that.

That's a ton of light especially for a 20 long with just anubias. I think you can definitely expect algae.

...out of pure desperation you can always use duck-weed as a floater...

That is a load of light... I have 108 watts over my 55 gallon and that is considered high lighting. What you have is uber lighting lol.

you should almost never go above 1.8 wpg of T5HO because it is almost impossible to provide your plants with enough co2 to out compete algae.

http://www.plantedtank.net/forums/lighting/105774-par-vs-distance-t5-t12-pc.html
here is a good article on lighting.

here is another good article on the myth of high lighting
http://www.barrreport.com/showthread.php/7503-The-high-light-requirement-myth