After some research and input from the great people here, I decided to have a major rescape of the tank. I think that the blasting sand, which I thought looked good, was causing heavy metal poisoning of the snails.
The blasting sand is a by product from the copper industry and could very well contain traces of metals like copper and zinc. Put that in a tank with rainwater and some peat and the metals can leach out. I should have twigged at the start when the vallis and anacharis melted. These plants typically live in harder waters where metals are less available Therefore they have less defences against high levels of metals.
I put the melt down to easy carbo but I had been using that in the bowl where both plants were going great. The plant that grew best was Rotala, which tend to grow in more acidic waters and have a better tolerance of high levels of metals.
Anyway I decided my tank of mining slag had to go.
I started with the clay balls again. Most of the roots from the plants had wound their way down and through the clay. So this was a no brainer.
I covered this with around 1" of Westland Aquatic compost as used by Tim Harrison. This I found to be very gritty compared to the aquatic compost I used previously. This was great as I could scoop it straight in without sifting out twigs etc.
On top of this I put around an inch of play sand. It was cheap and available and if kids play with it, then I doubt it is loaded with copper.
I cropped my java fern of pups and glued these to the rock.
When all finished it looked like this:
Just have to go through the whole cycling process again now.
Thanks for the help dw1305 and everyone else who has read and commented on my progress. Hopefully this time I'll get my jungle tank.
