New Tank Placement Troubles

[Acroart]

I am just getting back into the hobby after a 12 year break. Very exciting to see all the new advancements! I plan on setting up a custom rimless 120 gal heavily populated SPS tank with a unique dimension of 48" x 32" x 20". It will provide the lagoon look I am going for. I may even add a few mangroves to the aquascape. Also plan on doing a nice sump, fudge, reactors, automation, etc.

Problem is the only location I can get any tank larger than the 30gal that I'm currently running now is under an open stairway and next to a HVAC return. This could possibly introduce contaminants to the tank and my HVAC system? I think I can work around the HVAC return by keeping it open and accessible.
(If you notice I have an additional return just adjacent to it, this is for noise reduction and 2 could be considered overkill but it is nice. I also do not run filters in them as I have a high performance filter that is accessible form the garage and easily serviced.) I am considering possibly putting my external Zeovit and calcium reactors in the void for some eye candy and to save space in the sump area.

My stand will be custom aluminum and have a drain pan plumbed to the HVAC condensate line for the oh sh*t day. This wall does back up to my garage so I will have RODI and saltwater storage out there but all other components under the stand.

Now for the open stairs over the tank. I am concerned about dust, dirt particulate, hair, etc. Also when the stairs get cleaned mopping and getting wiped down chemicals getting in the tank. #maidproblems lol

Possible solutions I am thinking of.

-Stairs could be solved with a full canopy but I would totally lose the open lagoon feel I am going for. Maybe a low profile clear acrylic skirt around my LED T5 combo.

-HVAC eliminate the return on this side and live with the noise of the single HVAC return which is virtually silent now.
-See what happens maybe the airflow will keep everything dry and have virtually no effect at all

Let me know your thoughts and if any one has had good / bad experiences with a similar scenario.

Thanks,

Art

[d2mini]

I wouldn't block the return and I'd use a canopy if that's the spot you want to use.

[SalinFL]

Why not look into putting an acrylic sheet backing on the stairs? It will still maintain the open concept, allow light to shine through, but will protect your tank from contamination.