[vtchef]

I have always had covers on my tanks but just got some mounts for my light and cant use my glass top anymore. what are the positive and negative of not having a cover?

 

[Tex Gal]

These are things I can think of.

Pros
1. Light does not have to filter through glass and muck - more light
2. Easier access to plants
3. Less heat from light to tank as there is evaporation which cools and light is usually higher so heat dissipates easier.
4. Cool mounting for light fixture

Cons
1. Light is usually higher so some light is lost.
2. fish/inverts can jump/crawl out
3. more water evaporation
4. Lights need to have a splash guard of some type for electrical components.
5. Lights must be secured to make sure they DO NOT FALL into water.
6. Plants can grow up into lights.

 

[Zapins]

1 more for the cons list: the evaporation and heat loss will cause your heating bill to spike up significantly since a lot of heat is lost without a glass lid.

 

[nfrank]

Another big negative to open tanks -- higher humidity throughout the house. This can be a big issue with larger tanks in the more humid climates, like the SouthEast. In my old house, i had to install a ceiling ventilation fan in the "fish room." There are extremely quiet models which you hardly hear at all.

With smaller open thanks and in more arid areas, the evaporation is probably very beneficial particularly in the winter (no need for a humidifier), but can still make it more difficult to run the A/C during the summer.

In my new tightly sealed house, I have fewer tanks but my evaporation is still more than i want (i get condensation on a few of my windows) and i am stuggling with the decision to add glass covers to my tanks. :Cry:

I currently have Tek Lights with mounts over my open tanks, and plan to still use those lights+mounts if i custom make hinged glass covers.
--Neil

 

[yildirim]

If there is apossibility for you to keep the environmental temperature and tank temperature same or at most 1-2 degrees evaporation will be minimum and with an open top you will have a much better viewing pleasure IMO.

 

[gibmaker]

I used to use tank covers on my 125 gal until I upgraded to 4 CF's. They would actually crack my glass tops from the heat! I went through about 4 free replacements and then gave up.

 

[David Hui]

Easy access to plants is a big plus.

 

[nfrank]

If there is apossibility for you to keep the environmental temperature and tank temperature same or at most 1-2 degrees evaporation will be minimum and with an open top you will have a much better viewing pleasure IMO.

I agree that open tops are much better. However, I think it is difficult to avoid a temperature differential between the water surface and the air because of the heat that the lights generate.

I used to use tank covers on my 125 gal until I upgraded to 4 CF's. They would actually crack my glass tops from the heat! I went through about 4 free replacements and then gave up.

With Tek Light "legs", there would be air separation between the glass and the lights which would keep the glass from getting too hot. Other companies also make light stands.

 

[BryceM]

I'd like to suggest a third option.

I'm using what I think is a "best of both worlds" approach on my 180g tank. I use a three-sided canopy with an open top and front-opening lids:

You don't get a totally visually unobstructed view like you would have with an open top and hanging pendants, but you also don't get the same light spillage into the room. I need to add a small piece of wood along back to prevent critters from going up and over the edge. That still sometimes happens.

What I really love is the ability to open the lids and work on the tank. The metal halides and T5's sit up about 11 or 12" from the water surface. Believe it or not, this is plenty to allow scaping to your heart's content. The open top and back allow good air circulation around the fixtures which mitigates heating issues.

I used retrofit components to keep it fairly open:

I've never regretted the canopy look for a minute:

The MH fixtures have removable glass lenses and the T5s are open to the water but use waterproof end-caps. So far I haven't been electrocuted.