Substrate heating

Thank you Karen for your candid observation on the fact that ssh may not 
be cost effective.  I just got out the July '95 article on  a DIY warm 
water system (written by me).  When I wrote the article I had doubts as 
to the value of ssh and pointed that out in the sidebar are temperature 
profile through the substrate.  
While I don't think I mentioned it in the article, the only way to get 
steady convection currents would be to have the heater on all te time and 
then manage the "real" temperature of the water with auxillary heater 
and/or chiller.  Where I suspect ssh does some good is if the tank is in 
a very cold room and there is no way to get heat to the substrate.  If 
the heat loss through the bottom is high then the roots could be quite cool.

The variables involved make a simple conclussion inappropriate.  One 
person will not get the result of another unless all the variables are 
kept constant and there are too many to deal with.  

I have found the discussion on alternate methods of heating interesting 
too.  How often we come up with original ideas that are not very 
original.  We had five ways to heat the substrate and I have seen others 
posted here.  IF ssh were really effective then I would get a sheet of 
aluminum and place the tank on top of it.  I would then mount my MH 
ballasts or another other lite ballasts under the tank on the plate.  If 
this proved to be too much heat one could cool the bottom with a fan, put 
a spacer between the ballast and the plate, etc.  Those of us with racks 
of tanks are indeed heating the upper tanks from the light heat below 
them.  As mentioned in the article, "while we do not propose to turn the 
substrate issue into chaos, we suggest that there are inconsistencies in 
theory that can be challenged and te3sted.  An ongoing forum of 
controlled experiments could be of interest."

--Earle Hamilton from northern Michigan where coral once grew