Backyard Aquaponics
A place to discuss aquaponics

I have a plastic dome over my aquaponics tank and it is continually wet with evaporation from the tank. I am wondering if the nutrients from the water will be carried up with the evaporation. I have attached a picture of my proposed idea. In this system the water evaporating from the tank would collect on the plastic lid and run down to the edges. The bottom edge of the dome could be sloped in such a way as to cause all the water to run to one spot where it would drip down into the grow bed. Or there could be a round grow bed all the way around the fish tank and the lid would drip around the whole edge. The water would then run through the grow bed and collect in the sump at the bottom. You could then pick up the sump once a day or so and dump it into the tank. There would be an overflow on the tank as on normal sump operated system. There is the drawback of no continual pumping and no flood and drain. But it might work and use no power. You could also have a tank set above the fish tank that could be filled with water and drain at a set rate into the FT to provide a more consistent flow. Just looking for reviews and ideas about this system. I know you could not have nearly as high a fish load in the tank? I am thinking about trying it with a 55 gallon drum with gold fish as an experiment.

No nutrients will be carried up in evaporation.

it works with acid rain. I would have to rely on the sump changes for nutrients.

I think the acid gets in the rain from the atmosphere not by being evaporated from some acidic body of water.

The water condensing on the dome is going to be relatively free from the nutrients in the water. Think of distilled water, it is basically evaporated and then condensed. Most of the contaminants in distilled water are going to be from the air or the surface the water is re-condensed on, not from the original water supply.

This method might work for watering very tender plants that want almost no nutrients and are sensitive to salts and stuff. However, I don't think this method would serve more than a novel peripheral function since you still need to filter the fish tank water. If the only movement of water is from evaporation and then replacing that collected evaporated water, the ammonia levels are going to go up since the bio-filtration won't be happening.

Not exactly, Sulfur dioxide in the air (polution from burn't hydrocarbons) mixes with water droplets to create sulfuric acid and the precipitates as acid rain. Evaporation/distillation is how we purifiy water.

The evaporated water will have nothing in it.

however you COULD evap from the sump into the FT, thereby overflowing into teh GB. The GB will clean, the evap will clean better and the sump could be manually emptied once in a while, as it will be highly nutritious.
or the sump could grow NFT and evap out to the ft...
however what is possible is not always feasible... I don't like the preacticality of the system, it would be too slow or need to be too big.

just a thought I had. I know its not really practical but it would be fun if it would work.

Heat to increase the amount of evaporation would be a key factor. And allowing for the water to cool before entering the fish tank. Lose of nutrients not used in the first pass of the GB.

Cleaning the water may have a use to remove any metals etc.

+1 on no nutrients would go up with the evaporated water, but a good thought anyway.