Heat and Humidity Control, 1000 gallons

[malfist]

How is everyone controlling the heat and humidity of their aquarium rooms?

We're in our process of building a home and we're planning on putting in a 1000+ gallon aquarium in our basement. The aquarium itself will sit into a wall and behind it will be an unfinished maintenance room for the aquarium.

The question we have from our builders is what's the best way to manage heat and humidity in this room. Google isn't much help because this is pretty far outside the beaten path for standard questions. We live in kentucky and humidity during the summers is commonly over 80%.

This is the plan for the basement:

We'd like to avoid a chiller for the aquarium and instead use evaporation to cool the aquarium. We've currently got a 320 gallon and that's what we do for it. Fully automated ATO with an RO refilling it.


We had three thoughts on how to manage the humidity and heat, but we are far from the experts and would love input from you guys.

First idea: Vent in aquarium room
If we put an exhaust fan in the aquarium room, we can run the fan whenever the temperature or humidity reaches problematic levels in the room. This should create negative pressure and pull conditioned air from the rest of the house to both cool and dehumidify the room. As long as the house's humidity and temp is below a problematic level (it will be), this should work.

Second idea: Vent in aquarium room, ERV in house
Building on the previous idea, vent in the aquarium room to remove hot, humid air and pull cooler, drier air from the house. To save on HVAC costs, an ERV could be used inside the home to keep us from losing all the conditioning that went into the air that's getting sucked into (not out of) the aquarium room.

Third idea: ERV or HRV in aquarium room
If we put an ERV or an HRV in the aquarium room, we could ventilate the room with fresh air from the outside without sucking conditioned air from the house into the aquarium. However, my knowledge of ERV's and HRV's are extremely limited. Would one of these allow us year round humidity control? We wouldn't want to pull outside air into the room during the summer without dehumidifying and cooling it, or at the very least, dehumidifying it.

Would love thoughts, suggestions and ideas

 

[malfist]

Double post, can mods delete this one?

 

[AaronFReef]

Hanging in to see what people say. I don’t feel qualified for you to follow what I’m saying but I’ve looked a little into this myself; not much.

I have a feeling they’ll suggest the ERV/HRV in the aquarium room and if air can come from the aquarium room to the house as I’d imagine you’ll always have unless you maintain negative pressure in the aquarium room and it’s mostly sealed to the house minus a door or two, then pulling in air from your home and saving what energy you can out of it will probably be the most reasonable. I think an ERV is basically an air conditioner in terms of power draw/electricity usage if that plays into it for you.

There’s my (less than) two cents to get a bump for ya.

 

[JumboShrimp]

12’ x 6’ in-walk tank… beautiful project! Hope you get good direction on your question. Make sure this is a Build Thread so we can all enjoy it.

 

[rtparty]

My new 250g tank bumped my humidity up to 60% in my home and I live in dry air Utah. I've been running a 2000sf dehumidifier 24/7 and it barely knocks it down to 40-45%.

I've ordered an HRV (I'm 99% sure. One of them dehumidifies) and need to get it installed.

I'm sure you'll need some kind of air exchanger (maybe specific to that room) and a dehumidifier.

 

[FishTruck]

The good news is that your system is isolated from the house, so if you can just keep that room at 70 degrees and RH 50% or lower you are fine. Collecting and venting the hot wet air (main priority) and bringing in fresh air (helpful in the winter and no so much in the summer - but helps the pH of the tank) is the approach I would recommend for starters.

IF you can hood the tank, blow air in one side with a fan and vent it out with a 4 inch duct, you can keep the tank water cool and keep the hot wet air contained. Then....the air exiting is so hot, you might be able to use something like this - which is what I use - much cheaper than an HRV. I wrapped it in pink Styrofoam for winter. Just use an inline bathroom fan and a four inch duct and bolt the duct to one side of this box.... use the fan on the other side to bring fresh air into the room. I just leave mine on 24/7 365.

You will probably also need a dehumidifier - a big one. And, if you live in a hot climate, a window unit or mini split also in the fish room. Planning for it now will save you hassles later.

Making covers for your sumps will also help quite a bit. The PVC sheets from home depot are great for this. Check out Alex Gs builds.

Also, your house will probably be sucking any air it can find, so having another fresh air feed somewhere besides in the fish room will help prevent the fish room air from getting into the rest of the house. Don't count on a little fan in the aquarium room to be able to pull the negative pressure from the rest of the home. Have the HVAC do the math on that.

And, I know you didn't ask, but forget installing a wood burning chimney. Get an isolated system with it's own ventilation - or the smoke will come right into your fish tank.

And, for god's sake, don't waste your money on any steam injection system or anything at all that raises humidity in your house. New "tight" construction with a big fish tank will tend to run too humid.

(In my house, I have the above setup, plus I am going to need a second dehumidifier upstairs for the cold months - when the windows sweat at 50% RH (needs to be pulled down to about 20%)). That's a collection fan, an air exchanger, a window unit, and a big dehumidifier and still the house is too humid in the winter time. Part of that is kids taking two hour showers upstairs - so it's not all the fish tank's fault.

 

[Reefvision]

I have 300 gallons combined in basement and use a large dehumidifier unit that is rated for 2k square feet. Maintaining 55rh. You may want multiple units for safety “just in case” but that combined with Hrv unit should get it done . Good luck.

 

[malfist]

I have 300 gallons combined in basement and use a large dehumidifier unit that is rated for 2k square feet. Maintaining 55rh. You may want multiple units for safety “just in case” but that combined with Hrv unit should get it done . Good luck.

Do you know how many pints it's rated for? Do you have it in the aquarium room or in the basement in general?

 

[amoore311]

Relying on the existing HVAC and postitive/negative pressure is not going to accomplish your goal. But it will help.

You are going to need a commercial grade dehumidifier, and air conditioning in the summer time down there in the fish room.

An HRV/ERV will help, it's not going to make any appreciable dent in any issue you have with humidity until the humidity outside is low.

If the outside air is 80% humidity, you are pumping near 80% humidity into your house by bringing in fresh air. Keep that in mind.


I would go with a cheap single zone Ductless mini split to take care of JUST the fish room. On top of that you will still need additional dehumidification more than likely.


I also would not agree at all with cooling that space to 70 degrees. You are going to be paying a fortune running electric heaters constantly trying to keep 1000 gallons of water at 76+, when the room it sits in is 70.

I would personally aim to keep the fish room closer to 74-75 if possible, and target 50-55% humidity.

If you want that space to be 70 degrees, I would advise researching heating your tank with a loop off of your hot water heater. That's a whole other topic in and of itself.


I have a 220 in wall in the basement with an additional 100 gallon frag system in the 10x10 fish room behind it, 26x26ish finished room on the other side.

 

[Reefvision]

Do you know how many pints it's rated for? Do you have it in the aquarium room or in the basement in general?

I attached pics- the dehumidifier is in room behind tank and is flex ducted from tank area and dry air is sent to another area of basement but it all circulates well.

 

[malfist]

I attached pics- the dehumidifier is in room behind tank and is flex ducted from tank area and dry air is sent to another area of basement but it all circulates well.

Thank you, that is very helpful.

I think I might do something similar, bulky dehumidifier in the room, ducted to blow out into the adjacent mechanical room which will push it around the house.

Do you have problems with heat from the dehumidifier, or does that all go out with the exhaust air?

 

[Reefvision]

Thank you, that is very helpful.

I think I might do something similar, bulky dehumidifier in the room, ducted to blow out into the adjacent mechanical room which will push it around the house.

Do you have problems with heat from the dehumidifier, or does that all go out with the exhaust air?

There’s definitely a heated air that’s discharged from the exhaust of this unit . It’s adding to the a/c load. I am running my main houses a/c fan 24/7 to handle this so as to not dump a lot of heat just into our basement. Our houses tstat is set for 73deg and basement will normally be 70 average. Lights will also add heat to tanks water and area in basement. My 210 gal reef has a hood and I use axial fans (2) to blow air across water surface.

 

[Reefvision]

This heated air is dehumidified air so you don’t want to exhaust it outside,defeating its intent.

 

[FishTruck]

Relying on the existing HVAC and postitive/negative pressure is not going to accomplish your goal. But it will help.

You are going to need a commercial grade dehumidifier, and air conditioning in the summer time down there in the fish room.

An HRV/ERV will help, it's not going to make any appreciable dent in any issue you have with humidity until the humidity outside is low.

If the outside air is 80% humidity, you are pumping near 80% humidity into your house by bringing in fresh air. Keep that in mind.


I would go with a cheap single zone Ductless mini split to take care of JUST the fish room. On top of that you will still need additional dehumidification more than likely.


I also would not agree at all with cooling that space to 70 degrees. You are going to be paying a fortune running electric heaters constantly trying to keep 1000 gallons of water at 76+, when the room it sits in is 70.

I would personally aim to keep the fish room closer to 74-75 if possible, and target 50-55% humidity.

If you want that space to be 70 degrees, I would advise researching heating your tank with a loop off of your hot water heater. That's a whole other topic in and of itself.


I have a 220 in wall in the basement with an additional 100 gallon frag system in the 10x10 fish room behind it, 26x26ish finished room on the other side.

This is a good point.... there is going to be a bit of a battle between the DH and the AC, and, it is harder to keep the humidity down the cooler you make the fish room, so it probably will be much cheaper to run the room at 74 or even 80 degrees. In my system, however, if I do that my tank temp gets too high, plus, I find the fish room uncomfortable when it is that hot.

I still suggest that you have the Capability to cool it to 70 or 68 while maintaining a RH of 50% or lower. (After that, you can adjust the temp that you and your tank likes, and whatever minimizes the electricity usage). And this, I think everyone agrees, will require both a dehumidifier and an AC dedicated to the room - both of considerable capacity, and a way to dump the hot humid air, and deal with the quite variable fresh air that comes in to replace it.

 

[Ashish Patel]

My basement ran at 80-90% humidity last summer (sump in basement), Total water volume about 700 gallons, this past November i added a dehumidifier and it was not running at all during the winter bc humidity was 40%.

Right now it was pretty much running constant to keep it at 50%, so I changed it to 60% and its not being a complete energy hog. I also wanted to add a inexpensive air exchange but never got around to it but don't think it will do much since the tank is upstairs and humidity is an issue in NJ during the summer months, and summer months id just be adding humid air into the basement and winter time Id be adding cold air to the basement.

 

[malfist]

80-90% humidity! How did you not have mold everywhere?

 

[Ashish Patel]

80-90% humidity! How did you not have mold everywhere?

There was definitely Mold growing on the top ledge of sump, Alot of centipedes too. i just ignored it but luckily added a Dehumidifer before add 550 gallons of new tank water. Far more pleasant in the basement now!

 

[Ashish Patel]

80-90% humidity! How did you not have mold everywhere?

Reading your msg I just decided to switch humidity settings to 50%. It as currently 58% down there and set at 60%

 

[maroun.c]

no experience with ERV/HRV here unfortuantely so not sure if they would help better.
we get hot and humid summer and not too cold by dry winter.
so the hiumidity is mostly in in summer time. I tried running a dehumidifier, not a huge one actually and it worked fine but was adding to the overall electrical consumption.
I also had an issue colling the tank in summer which required couple chillers.
2 yers back i installed an AC unit in the basement (fishroom) where I run most of my tanks and all are connected to my 400G at home ( total system volume about 1250 G) and it worked great chilling the whole system with chillers off even, and also reduced humidity to excellent levels. the only difference is I have about 6 tanks in the fishroom so much more air water contact so not sure if it would be different with a single tank in the room.
winter time I find the hot air from the AC unit is creating a humidity issue so not sure if I'll couple it with the dehumidifier again next year or rely on heaters to heat the water.
any venting in summer or winter I find causes more issues with temperature (then again I don't have access to ERV/HRV here so might be better for you using those)

 

[Ashish Patel]

I am pretty stoked with my latest electric bill of $293. I am sure its just as estimate bc I just viewed the email msg and its probably higher but here are my energy hogs

Running a 18000 gallon pool with pump on 8 hrs per day (sometimes more)
A/C all day at 72 degrees.
400 gallon display and basement sump room.
125 gallon second tank
40 gallon QT Tank.
Dehumidifier in the basement on constant timer based on humidity.