Help - Am I going to poison my fish with the background I built ? (NetMax please read)

Hello,

[NOTE - this message covers some of what came out of the thread "How 
many times should I wash out the tank before adding fish ?" currently 
here. I posted this separately as I wanted to get more opinions, 
especially from people who have built backgrounds like mine.]

Some time ago I started a thread "What do I use to stick rocks together 
?" (see Message-ID: <[EMAIL PROTECTED]>) and 
was advised (mainly by NetMax with the help of some useful links) to 
build a fake rock background out of polystyrene.

Briefly what I did was get some polystyrene ceiling tiles and stick them 
together to make a sheet big enough for the background. I then cut some 
rocks out of bigger bits of polystyrene and stuck them on the tiles with 
aquarium-safe silicone. I then painted it with non-toxic water-based 
paints (from Toys-R-Us, 99p for a litre) and gave it two coats of 2-part 
epoxy to seal it.

Well, after working on it for quite some time, I finally finished it and 
was very pleased. It looks very realistic and has loads of caves for the 
cichlids to hide. I stuck it in the tank and prepared for the first 
fill.

I filled up the tank for the first time yesterday. To my horror, about 
an hour after filling, I saw what looked like streams of milky substance 
coming off the background. There were also loads of brown particles 
coming off the background. This continued most of the day. By this 
morning, the brown particles appear to have stopped. There are quite a 
lot on the floor of the tank and on horizontal bits of the background, 
but I don't think any more are coming off. The milky stuff also appears 
to have stopped streaming, but the tank water is very milky.

First, does anyone have any idea what could have caused this ? I am 
pretty certain that the epoxy sealed the paint in all over. I don't 
understand how the brown particles, which look like paint powder, could 
have got off the background. Also, anyone any idea what the white stuff 
is? The epoxy I used was West Systems epoxy and is designed for boats, 
so is definitely waterproof. I found the stuff from someone else in this 
newsgroup who used it in his tank without any of these sorts of 
problems.

Anyway, I intend to empty the tank tonight, wash the background well to 
remove any more particles, then clean out the gunk from the bottom and 
refill. If the refill remains clear and clean, I will risk some small 
cheap living creature to see if it survives.

I'm a bit desperate here. I realise it's almost impossible for anyone to 
say clearly what has happened, but I'm just hoping someone may have some 
ideas. I'm really worried about the idea of putting fish into a tank 
that may contain poisons. On the other hand, the thought of ripping out 
the background upsets me too. I worked very hard on it for quite a long 
time and just don't have the time or heart to make another. I'm not even 
sure I would get this one out cleanly as I stuck it in well.

Any advice would be very gratefully received. TIA.

--
Alan Silver