Well i dont want or meen to alarm you unnecessarily but it might depend on what materials you have used. I have heard some people have had to leave there builds for upto and over 4 weeks to compleatly get rid of smells and stuff as the heat from a viv can make the smells come back. Is your build stuck/sealed in ? If not i wouild remove it quick and give it longer to breath.
Imo if he has never done this before and has only done it and acted differently since you put the build in, that would be the first thing i would look at. Dont get me wrong im not saying he hasnt got parasites but that would not be my first thought if you know what i meen! Ive heard of beardies convulsing with RIs due to high humidity now the fumes would also affect his breathing, wouldnt they?
Well he hasnt been in there long has he? i would get as much fresh air to him as poss, even pop him in a RUB until you get the old viv set up. I wouldnt rule out the cricket leg thing but you know what size crix he has as long as there no bigger than the space between his eyes i dought it would be that. I wouldnt panic or anything but i would get him out that viv and back in his old viv asap. Oh and dont get rid of the new one just needs more time to air i would say
Take him out nd put him in his old viv. Could be the fumes or high humidity (as said before). The only other thing i know of which causes convulsions is calcium deficiency, but i dunno why he'd suddenly have that lol