just another rack question

I have drooled over most of your guys great set ups. I am on a TIGHT budget and wanted some shelves so went out and priced them. Well push came to shove and I could only afford the $20 metal shelves so I got them thinking at least each snake will have its own tub.

Well I got them set up but am having a hard time controlling the temps. Is it because of the metal? Is this why no one uses metal shelves? I am using a 30 q tub for my adult and 1 40q for another adult, 2 16q for my sub adults and 2 shoe boxes for my babies.

I have a 3" flex watt on the first two shelves going along the entire back under the tubs (two tubs on each shelf: one shoe box and one 16qt) the other 2 shelves have one piece (ft) of 11" flex watt under them. The one shelf the flexwatt covers 1/3 of the entire tub but the other shelf the tub hangs over the shelf (have it secured so it cant fall off) so about 3" hang over the edge so it is without heat under it.

I actually have one tub (a 30Q) that is not set up yet as I had my male in with my females alternating him between them. but decided to get him his own tub so he could rest.

I got some scrap wood today and am going to put one piece under the lowest shelf and use the other to make another shelf so my boy can have his own shelf with his own flexwatt.

Should I put wood under the other tubs as well and put the flexwatt on top of the wood?

My babies are only 200gs my sub adults are about 500 and my one boy is 1500g, one girl is 2100g (she is in the 40q) and my other girl is 1800g (in the 30q)

I know my discription is not the best. I am attaching a pic. You can see both peices of wood on the bottom shelf as I haven't put up the boys tub/shelf yet.

SOoooo. how do I control the temps better? I have all the flex watt attached to a helex thermostat (the probe is taped to under one of the shelves)

http://img.photobucket.com/albums/v3...s/P1020825.jpg

sorry for the side shot