Ok since i have changed to sand, my fish seem to sit on the bottom till i turn the light on. I have lost one guppy recently that was doing the same is there a problem? My plants are rotting as well should i remove them?
Ok, I used that same stuff in my tank for 2 years without problem...so unless it has been changed - it shouldn't be the sand alone which is causing the problem.
Was the sand washed?
Also, to ask the obvious - have you checked the Ph levels and ammonia levels?
But you will also need to find out why you are getting ammonia. How long have you had the tank? It's possible I guess, that some beneficial bacteria we removed with the old substrate.
Have you cleaned your filter lately, or made any changes to it?
I have not made any changes to it, i took it out and bathed it in some old tank water as it was running slow but i only opened it and moved it through the water, i did not take out any sponge etc...
One thing that happend to me before is that my filter got clogged up with sand which made it run slow. So I got a small ammonia spike. Could be that the slow running of your filter is preventing it from getting rid of all the necessary ammonia. It maybe worth taking out one of those sponges and given it a good clean - just incase it is clogged.
Also make sure you wash it in tank water. You will lose a little beneficial bacteria, but not much and it will repopulate quickly. You need to get the flow of your filter back up to full speed, else you are going to keep getting ammonia problems.