Brett-
First of all, great tank, I have been admiring your build for a while!
To digress from the discussion of your fish/corals and dosing etc, I have a question about the state of your fish room now that the tank has been in there for a while, because I am eventually refinishing my basement, and an in-wall tank is my dream!
1) Have you had any water damage to the drywall or any moisture/mold problems from evaporation in there?
2) Did you insulate the room and does it abut any foundation walls?
3) Do you know what the relative humidity is in the fish room and/or in the rest of the basement?
Thanks in advance!
Hi DoctaReef. Thanks for the kind words.

I'll try and answer your questions to the best of my ability.
1. No moisture, mold, or water damage present.
2. The sump room is located in the basement as such so only one wall is on a foundation wall. I insulated this wall with Kraft-faced insulation, no vapor barrier. The other walls are interior wall so no insulation.
3. The relative humidity stays between 55-65% in the basement which is normal for my area/climate. The upstairs living space stays around 45% year around.
As for vapor barriers, I personally do not recommend using them for areas of the country such as the midwest where I live. In fact, it's becoming more likely that it's against code in many parts of the country. Reason being is with the ambient humidity along with a concrete basement which tends to wick water towards the inside, you can trap moisture behind the plastic vapor barrier. The worst thing you can do is put a vapor barrier on top of the stud wall with insulation behind. This is a mold factory. The best product to use against concrete is to glue up rigid foam insulation and seal the joints with foil tape. Then you can frame it out and use Kraft-faced insulation so the wall can breath up and through the joist space above. Again, no plastic.
In my sump room I used 1/2" green board on the walls and regular sheetrock on the ceiling, as stated in code. I coated the walls with Moore Aura semi-gloss latex paint on the interior walls, again to allow the walls to breathe. I'm a big fan of allowing living spaces to breathe from the inside out, it's where trapped air and moisture behind the drywall really start to play havoc on those spaces. I also have a 80cfm DC ventilation fan along with a supply and return from my HVAC to keep the room climate controlled. Honestly, the supply and return are the biggest factors in keeping the room the same temp/humidity as the rest of the basement. Along with the vent fan it works great.
This is a heavily debated topic and none of this is intended to start an argument. I have a few friends in the building trade and I researched and consulted until I came up with the best solution for me. Biggest thing is to stay within code. If the space you build is climate controlled there is no reason it shouldn't stay within the same general temp/humidity as your living space - and without going overboard or breaking the budget.
