Glass Tops

[BeltwayBandit]

Ok.  Why does everyone bash glass tops.  I realize that every situation is unique and different.  Here is what I run, and some of the different setups that I have tried and what I have seen.

 

My "normal" mode of operation is full glass tops over the entire tank except about 2".  I have a 20 long sump that is completely open underneath.  I am running 2x250W XM 20k MH lamps fired with hellolights electronic ballasts and two Radio Shak 120v fans that are on the same timer as the lights(fans are mounted next to each other and blow in along the center of the tank perpendicular to the parabolic fixtures for the lights).  I do not use any actinic supplementation.  I like the color it is a bluish white.  No yellow.  I have several soft corals and a Long Tentacled  plate coral that all seem to be doing very well.  All of the softies have shown a ton of growth since I got them at the frag workshop.  In particular the colt frag that I got has at least doubled.  From the single branch that I started with I already have three branches, one large and two small.  So, in my limited experience I would say that I am getting good growth. (Just a side note about performance of XM 20k w/o supplementation)

 

Here is what I have noticed in terms of temps and evaporation.  When I leave the tops partially opened exposing approximately 1/3 of the surface of the tank I evaporate over 2 gallons of water per day from my system and my heaters are running constantly to keep the temp at about 78-79 degrees.  Completely open w/o tops comes close to 4 gpd.  When I close the tops except for the 2" or so in the back my temp stays at 80 degrees and the heaters are on much less and I evaporate less than a gallon of water per day.  I am aided by the fact that the aquarium is in the basement so the room itself is always on the cool side to act as a heat sink for the lights.  

 

Unfortunately I don't think that I can get rid of the tops.  My stand came with a custom canopy that is not really high enough to mount the lights safely over the tank unprotected.  The biggest drawback of the tops is that I should have to clean the salt off of them on a weekly basis (it usually slides to the 2-3 week range because the top is a pain to take off and I have already broken 1 bulb in the process when it slipped.. oops there is a $65 mistake.)

 

So, I don't know if there is a question here, but I just wanted to point out that glass tops can be worked around with the right conditions and they do provide some benefits.  Maybe don't be quite so quick to dismiss them?

 

BB

[OUsnakebyte]

I wish I could have them, b/c like you, I lose quite a bit of water to evaporation every day.  But, without the tops, my temp runs about 82, and that is with two fans in the canopy.  I put the tops on one day and the temp shot up to around 86-87.  (75 gallon, two 150 HQIs and two VHO actinic).  So, I am forced to add water daily.

 

I'm not sure if there is a concern with the glass filtering out some of the proper light spectrum.  Maybe someone else could comment on that?

[michaelg]

For me it has always been needed to go topless keep the tank cool...You are lucky you can get away with it.  I need every bit of evaporation I can get.  With a sump and a good skimmer, you will get good gas exchange, which could be an issue for some.  There is also some loss of light intensity when it passes through glass.  And as you mentioned- you have to clean them.  Added benefit is you don't need to worry about fish going carpet surfing.

[Sph2sail]

My understanding (old wives tale mebbe?) is that glass is a filter for all UV radiation.  I was under the impression we are trying to get UV into the tank, as some of the zooxanthelae need it.  That said, I recall being advised to dump my glass tops pretty early on by various club members.

 

Like most already, I evap about 2G/day running two fans on an open top tank.  Make-up through a float switch controlled Kalk reactor.

 

Personally, I would turn off the fans, open the top and see how that works.  Esp if your tank room is cool already.

 

just a thought.

 

s