You could and, to be honest, evaporation shouldn't make too much of an issue...PROVIDED you're aware of the potential effects of it and what it can do to your tank parameters.
I top off evaporation with RO/DI water in my FW tanks, but I also do weekly water changes.
In brief, I needed riparian pants for nitrate reduction. I created this "bamboo forest" because the inhabitants have historically uprooted or destroyed every aquatic plant I've tried and eat floaters like their brine shrimp! In particular the tank that will see this has Oscars and pacu's in it such that anything but these plants were knocked down or uprooted.From my experience of aquariums in the late 60s, the 70s and 80s, tank lids were always, ALWAYS, considered to be essential, especially for tropical tanks.
Not only did the lid hold the lighting, be it bulbs or fluorescent tubes, but it helped reduce evaporation, minimised fish loss through jumping and, perhaps most importantly, it stopped dust and household airborne contaminants reaching the water surface.
Today, I see this popular trend for open tanks and, whilst I can appreciate the aesthetics of such a tank, I'm wondering about jumping fish and those aforementioned 'airborne contaminants'?
The increased emphasis on plants is, as far as I'm concerned, a Good Thing and I do like those tanks with the plants growing up and out of the water.
I can also appreciate the nice lighting now available and the ability to get that 'different' view of the tank from above...although I suspect that might freak the fish out somewhat, as a potential predator suddenly appears above, casting its predatory shadow.
Another factor with the light would be an actual reduction in the control of the light spectrum entering the tank. With a lid and modern lighting, the majority of the lighting can be controlled, with ambient lighting only entering from the sides left clear. Without a lid, ambient lighting enters from all five sides.
I can also appreciate the visual impact of a clear glass box, with colourful movement inside it, with visible frames and equipment kept to a visual minimum, although, again, I question the effect of such an open arrangement on the well-being of the fish.
Do those of you who have such tanks use a glass cover and, if not, how do you stop your fish jumping ship, minimise evaporation and stop airborne contaminants?
There’s not enough evaporation going on to significantly affect a house’s structure. My houseplants surely do appreciate the added humidity though.
Is there not a danger of messing up your water hardness and therefore PH by adding RO water with no buffering? Over time there is maybe potential to drop your PH buffer capacity enough that you will start getting wild PH swings.
I strongly suggest that you get a lid and use it.
Not an issue because very few people do an exact volume water change every time- If, for example, you generally aim for 30%, sometimes you do 33% other times 28%. Over time, the amount of change is minuscule in either direction. If it worries you do a larger % water change (or an extra one) once every few months to increase your kh….P.S. Your tap probably doesn’t have exactly the same kh (or any other value) every time you do a water change. This is one of the reasons it’s a good idea to test parameters every so often.
He is only 3 inches right now, The tank is half filled, so he cannot jump out. He is going into a new, bigger tank as he grows. They Can't they jump a foot in the air can they?
My lad had a 20 gallon long and it was filled to about an inch off the rim...they swim alot more than you might think. Mine would literally swim about 40 laps every morning after he had eaten and would often seeminly rev up on the sand and shoot upwards in play and to get a lungfull of air....and would headbutt the lid almost every time when he breached the surface.
