Condensation on glass and Fertilizer

 Subject: Condensation on glass
> Dear Folks, 
> 		I have a rack of 4 - 15 gallon tanks 2 rows of 2 
with a 
> single 40w vita lite.  I'd like to grow low light level plants s
> of light isn
> isn't the issue.  The problem I am having is with the condensati
> tanks I use 1/4" glass and then 1/4" plexiglass on the other two
> plexiglass because I can have it cut to the exact size of the ta
> hole cutter I drill a hole in the corner through which I can fee
> seems to have property's (properties?) which increase the number
> droplets from evaportation visibly diffusing the light more than
> covers seem to.  Even the glass covers collect water that does n
> off after the lights come on.  I know I could leave the tanks wi
> but I'm concerned with the amount of Co2 that I'd loose, the dry
> floating plants, jumpy fish and excess H2O evaporation.  Eggcrat
> only one of these problems so I'm kind of stuck.  Any Ideas??!!

First let me point out that if your sponge filters are air driven, 
you ar not conserving CO2 by keeping the tanks tightly covered.  
You are pumping atmospheric air under the cover anyway!  That 
said, with low light and tolerant plants you probably don't need 
to worry about it anyway.

As far as the condensation is concerned, if you have warm damp air 
on one side of a piece of glass and cooler air on the other side, 
you _are_ going to have condensation.  I wouldn't worry about that 

Subject: fertilizer
> I have small gravel and laterite (from Thiel) in the sub-strate
> I received a large group of discus aquarium plants from Deleware
> Aquatics. I also have the plant food tablets from Deleware Aquat
> I am using the Duplaplant 24 daily supplement.
> My main question is: (I crushed the Del Aq tablets and placed it
> water, not the substrate), DO I need to be placing fertilizer, i
> addition to the laterite, in the substrate?   (I am using DI wat
> will soon be adding a Sandpoint fully automatic CO2 injectiopn s

I would never use DAI plant tablets in the water!  They contain 
both nitrate and phosphate (among other things).  If you have a 
very low fish load, and do not have very bright lighting, they can 
be a useful substrate additive.  But with Discus in the tank, you 
will have more nitrate and phosphate than your plants need anyway.

Karen Randall
Aquatic Gardeners Assoc.
Boston, MA