Glass tops and oxygenation

[Larry L]

Has anyone run into problems with glass tops keeping a tank from staying well oxygenated? I've got a basement tank with just a HOB filter, no overflow or sump or skimmer that would normally help keep things oxygenated. It currently has egg crate over the top, but am thinking of replacing that with glass because I'm getting a ton of evaporation and a lot of condensation inside the canopy. If I use glass and leave a gap at the back for cords and such, is that enough to allow for air exchange? Or would I need to add an airstone or something?

 

[Peace River]

You may also want to consider surface agitation, bio-load, and temperature.

 

[AlexG]

The HOB filter should provide enough surface agitation and oxygenation on its own. Having additional pumps provide surface agitation would also provide more oxygenation. The glass top itself should not be an issue in hindering oxygen as even small holes for cords and the HOB should allow for a good gas exchange.

 

[King Turkey]

auto top off?

 

[SDK]

A skimmer would definitely be a good purchase in that situation.

Some years ago TFH or FAMA did some testing and found a measurably higher amount of CO2 concentrated beneath glass lids. If I remember correctly, the gap was not very helpful since the CO2 was heavier than the ambient air, and tended to pool in the gap beneath the hood. The only thing that was really effective at countering it was an airstone.

How much this will affect your particular tank, I don't know, but I thought you would appreciate the data....

 

[Joseph Disalvo]

I don’t see any issue with a glass canopy other then salt creep from splashing causing a little drop off of par on your lighting .. nothing major tho. Go for it, save that water ✌

 

[EMeyer]

I use glass lids on all my tanks to minimize evaporation.

Between the skimmer and return to the sump, there is a TON of aeration in my tanks and I consider it a design flaw to let the RODI evaporate away.

If you had no skimmer or sump I could imagine gas exchange problems.