Lids on large tanks - effect on gas exchange?

[kattz]

On this 400g that we are planning, I've been warned that having a tank that large in your house usually will contribute to mold. Lids have been recommended.

This tank is 48 x 72, so twice the surface area as a 24 x 72.

I don't have a problem with lids. But what is the effect, if any, on the gas exchange for the aquarium?

Kev

 

[Randy Holmes-Farley Verified Community Expert]

It will reduce it, certainly. A skimmer might mitigate the issue.

 

[TCoach]

I see a couple of options depending on the setup:

1. Run a dehumidifier - Could raise temps in area.
2. Use a hood and use fan(s) and duct work to exhaust the air outside.

Look at some of the work that Ryan from BRS did with his 360 when he had it at home. Might have some more ideas there.

 

[Treefer32]

I've ran a 340 gallon plus 75 gallon sump for 3 years now in my home (it's in the furnace room) - In wall display. There is a ceiling over the tank that I hung the lights from and I have netting over the tank.
Based on the amount of salt water floods I've had over the years. I highly doubt I'll have any mold at least in flooring. As Salt and mold are complete antithesis of each other. My understanding is that salt kills mold spores instantly. So, Yaay for those of us that have created more floods than they care to admit with salt water. Each flood kills mold spores!

That said, the evaporation (above the tank) I've heard can cause major issues. I had a fellow reefer that his tank was on the main floor and attic above that. The ceiling and all the insulation at some point was saturated with water... evaporated water (no salt). They had to redo the entire ceiling and insulation and pull stuff out.

That said, I'm struggling with evaporation myself. My wife is having lung issues recently and the doctors believe it's viral and she may be developing what they call viral induced asthma. It could be permanent or temporary. But they asked if we have a lot of humdity.

So, I'm looking into glass covers myself. I have 75 gallon water containers for water changes and top off. I go through about 60 gallons of water every 40-50 days. It just refilled last night, so I'm going to calculate the exact number of days here. But, That's over a gallon a day. I'm looking at getting glass lids for the tank at least. My Sump has too much equipment I can't put covers on it. But putting covers on the display should be huge in helping reduce general humidity. I've been told that the water falling through our larger plumbing (1.5" for me) has more than enough O2 for gas exchange while limiting evaporation. Plus, if you run a skimmer that should help oxygenate the water as well.

If I were you, knowing what I know now, I would definitely add glass lids just to help keep everything in the house safe.

 

[Fishnut]

I have been running 350 gallons worth of marine tanks in my house for 10 years and discovered that the attic plywood is covered in black mold. The inspector said the warm humid air from my tanks makes its way to the cold attic in the winter and condenses on the ceiling of attic causing mold to grow. I now need to replace not just roof shingles but also the plywood. $$$. I’m now a believer of lids and exhaust fans in rooms with large aquariums.

 

[alton]

When I had my Planet 310 I had glass tops with no issues. The person who bought it from me did not use them the first month, but after going through a bunch of top off water he now uses them with no issues and no changes to his coral.

 

[Treefer32]

I have been running 350 gallons worth of marine tanks in my house for 10 years and discovered that the attic plywood is covered in black mold. The inspector said the warm humid air from my tanks makes its way to the cold attic in the winter and condenses on the ceiling of attic causing mold to grow. I now need to replace not just roof shingles but also the plywood. $$$. I’m now a believer of lids and exhaust fans in rooms with large aquariums.

I don't know if this helps or not, but I run my dehumidifier right next to the tank, fan running all the time and set to 50% humidity. I also have my return air vent for the basement in the ceiling about 3 feet from the tank, plus the tank is in the furnace room where there's a lot of air flowing through the furnace. I don't know if that helps or not, but, I will definitely be putting lids on my tank. I just have find someone to make them.

 

[kattz]

This is all good info and represents exactly what my friend (he runs a large tank maint business) said would happen to my house.

Lids for the tank are going to be included. Not glass, acrylic. I'm running LED's, not metal halides, so should be OK.

Our overflows will be open to the house and should allow enough for the gas exchange based on what Treefer32 said.

Sorry to hear about your wife...

Regarding the skimmer, there is an inlet pipe for the furnace and water heater. I'm just going to run my inlet hose to that pipe for the skimmer.

Regards,

Kev

 

[TCoach]

This is all good info and represents exactly what my friend (he runs a large tank maint business) said would happen to my house.

Lids for the tank are going to be included. Not glass, acrylic. I'm running LED's, not metal halides, so should be OK.

Don't acrylic lids warp over time? Think I've read about recommendations for glass or maybe polycarbonate for lids.

 

[Cory]

Do what i did, run an air pump from outside air into your glass lid. Air exchange wont be impacted as much and youll get a nice ph boost.

 

[TCoach]

Do what i did, run an air pump from outside air into your glass lid. Air exchange wont be impacted as much and youll get a nice ph boost.

I do something similar with my tank. External air pump sending outside air into my sump (wooden airstone where return comes in) and skimmer intake (before CO2 scrubber). pH boost/stabilization has been nice.

 

[Cory]

I do something similar with my tank. External air pump sending outside air into my sump (wooden airstone where return comes in) and skimmer intake (before CO2 scrubber). pH boost/stabilization has been nice.

Nice! My gas oven made my ph go to 7.6 some nights when cooking. The lid plus outside air in it, in the overflow box and in the skimmer keeps my ph 8.1 to 8.25 at 8.5dkh. Very happy now.

 

[Bruce60]

This is a very interesting discussion. Allow me to add my observations.

We built a home in Nashville where we built-in two large tanks with a total water volume, including sumps, of about 650 gallons. We had also built the home using insulated concrete block forms (essentially building a home with Legos and then filling the insides of the Legos with steel reinforced concrete. The home was so air tight that we used to get condensation on the insides of the windows in the winter. Eventually we had to add a fresh air exchange into the geothermal system to move air in and out of the home. Interestingly, the people who purchased the home from us removed the tanks, yet continued to have similar humidity issues, although perhaps lessened somewhat.

In our current home we have a 150 g display (about 170 total volume). Have not noticed the same issues, but this is a traditional construction with more air exchange naturally. Tank has screen top, but the sump has glass lids to keep humidity in the stand to a minimum. As a measure of how much water the system puts into the air, I typically go through 5 gallons of ATO water in 3-5 days. I actually lose more water in the summer when I am running a ceiling fan in an adjacent room to move air and cool the tank than I do in the winter when the home is colder and dryer, but with no fan. I like to think of this tank as helping bring some humidity into a dry winter home in the northeast. Now I wonder if I need to check our attic.

 

[kattz]

I checked - the lids will by polycarbonate. The air-stone is interesting.

 

[Treefer32]

My wife and I had our home built 5 years ago. Being in the north, the builders built the homes so tight that... I can't think of a good analogy this early on Monday morning. Our first year in the home I didn't have the tank operational, but water condensed on the windows and we didn't realize it right away due to having good quality blinds put in and they remained closed in many rooms. Well, when we noticed it in mid winter and checked them all, they all had mildew and fuzz growing on the window frames at the base and a puddle of water damaging the wood and the stain. We wiped all the windows and bases down thoroughly. Carefully using bleach on all the mold and mildew to make sure it was all killed. Then I implemented the tank and daily we had to wipe the windows down. I got a dehumidifier and keep it in the fish room and it runs 24/7. Since then, no condensation on the windows.

I've talked to several people and they said the new homes are built sealed tight to ensure maximum heat efficiency in the cold winters. Which leads to a different issue of very little oxygen exchange in the home and very little room for humidity to get out of the house.

I did have the furnace installed with the option for an air exchanger. I'm getting quotes on glass lids for my tank, but won't have the sump closed up, so, curious on peoples thoughts on an exchanger?

My builder had mixed thoughts on it, he said it's not humidity control it just exchanges air with outside air... I get the difference, but, is it worth the $1500 it'll cost to install the unit (or more probably now)?

As to running a skimmer line. I've thought about that too, but, in the summer the city aerial sprays and has vector control trucks drive around neighborhoods releasing gases into the air to kill mosquitos. One year we had a huge die off of butterflies as the mixture may not have been right or something. Dead butterflies covered the ground everywhere. Another year a kid was keeping some toads in a kiddie pool. They were all doing awesome and he woke up the next day after aerial spraying and all the toads on the ground were dead. The city cited that the spray is safe for humans but may not be safe for amphibians since it's meant to kill of water dwelling mosquitoes.

Having that pulled into my tank seems like a really bad idea in the summer..... Maybe a carbon reactor on the intake might deal with it, but I'm not willing to take that risk. . .

 

[p72c10]

I have a skimmer in my sump that runs 24/7! How confident are we that it will cause enough gas exchange? Also several cuts in the PVC my water flows down through and they make tons of bubbles. I recently cut 3 24inch by 24inch acrylic reduce evaporation and then it hit me GAS EXCHANGE. New to the game smh

 

[Randy Holmes-Farley Verified Community Expert]

I have a skimmer in my sump that runs 24/7! How confident are we that it will cause enough gas exchange? Also several cuts in the PVC my water flows down through and they make tons of bubbles. I recently cut 3 24inch by 24inch acrylic reduce evaporation and then it hit me GAS EXCHANGE. New to the game smh

You have a tight fitting lid?

 

[p72c10]

You have a tight fitting lid?

No they fit pretty good not to snug might run a 1/4 acrylic sqare stock across to prevent Boeing. I hand cut them so they are snug us some spots and just a little open to air in a couple spot they can't be seen at all so I didn't prefect them

 

[Randy Holmes-Farley Verified Community Expert]

No they fit pretty good not to snug might run a 1/4 acrylic sqare stock across to prevent Boeing. I hand cut them so they are snug us some spots and just a little open to air in a couple spot they can't be seen at all so I didn't prefect them

If you blow some air into the space under it, the concern is eliminated, but skimmers will help if aeration is limited.

 

[jda]

I had a large acrylic tank with lids. I found that if I kept the lids on the tank then the air that got out was more saturated and the effect on the home was the same... less escape with more humidity. The lids also kept the tank very warm - tanks this size usually have pumps that can heat the water a bit.

For me, the humidity in the house was about removal with the AC unit or dehumidifiers and did not matter how much I tried to seal up the tank.

Also, lids cut down too much light for the corals... very hard for reefs. Also for reefs, you need to evaporate water if you want to run kalk, so not an issue for some, but large for others.

In the midwest with high humidity we never had any mold. We ran the AC and had a larger home-type dehumidifier in the basement with the tank. We did not need to use the humidifier for the furnace in the winter months. Like 40-45% humidity all of the time, or a bit lower in the winter.