Ideas to reduce evaporation in my tank
 

I am looking for ideas on how to seal the top of my tank to greatly reduce evaporation. I would like to make a sealed canopy. Has anyone done this to their tanks? IS there any down-side to sealing the top? If anyone has pictures of things you've done to the top of your tank to reduce evaporation, I would love to see them!

You may end up having a lot of heat issues if you fight evaporation. Evaporation is great in helping reduce heat. I have a 120 with a canopy that has an open back. I have 2 fans blowing from that back opening and I lose about 2-3 gallons a day. I'm not sure what kind of loss you're experiencing. My 2 cents and that's probably all its worth...he heee

You can seal the top of the tank and reduce evaporation... but the cost is probably more than the gain. You'll have a harder time controlling temperature, and you'll have a much harder time controlling the ph, which is an even bigger concern. The water in your tank needs to exchange gases with the open air: trapping it in there can risk buildups of CO2 and lack of 02 in the water.

imho, the only real reason you'd want to cover the tank is to keep jumpy fish from jumping out of the tank.

Installing a chiller may help alleviate this issue by mechanically cooling vs evaporative cooling. In NEOH, its kind of a waste though unless your house gets really hot. No matter what, you will still have evap, especially in winter when you ambient humidity is lower.

I agree with the suggestions of the others. The cons outweigh the negatives in most cases as you will drastically reduce gas exchange.

evaporation is your friend if you harness its power, and get an ATO

Thanks for the advice so far. Seems like actually sealing the tank is not the way to go. Is there any way that anyone knows of to re-direct evaporation back into the tank? I'm thinking that if the hood had a different shape, I may loose less water. Does anyone have any ideas for this?

To the best of my knowledge, any method would end up closing off your tank. The only way I know is to condense the water vapor like a distiller or dehumidifier. However, it would not be energy efficient.

What is you motivation for reclaiming evap, humidity or water loss?

For humidity, you can vent the room or use a dehumidifier in the winter (which really shouldn't be an issue due to the low humidity heating your house causes). As far as water loss goes, setting up an ATO is a heck of a lot less work than it sounds like.

use the evaporation to help you, get a kalk reactor and dose kalk via Auto Top Off

You'll really be hard pressed to find SW reefers that don't simply top off their tanks as needed instead of worrying about the evaporation rate. The downside is that your topoff water needs to be as pure as possible: any contaminants in the topoff will build up in concentration as pure water evaporates, but contaminates are added back with the replacement water.

At that point, only water changes can reduce the levels again. This is why many people opt for some form of filtration unit to produce pure water for topoff (and then also for salt mixes while their at it).

yes RO/DI is necessary for reef tanks.