Speedy’a shell changing colour

[Speedy101]

Hi,
My tortoise speedys shell is turning yellow when he was originally dark green.He is a spur thighed tortoise and is nearly 12.Im aware he has some pyramiding however he came to us like that, his diet now consists of dark leafy greens, weeds, dandelions , bell peppers and also a calcium supplement. He lives in our greenhouse during the summer and has a UV light and a heat lamp which he basks under daily.He had a similar problem last summer but the vet said he was ok however it’s more prominent this time round so I was looking for some opinions.
P.s He is acting normal and eating/going to the toilet fine.
Thank you!

 

[Tom]

Get a brick and lay it on its side directly under the heat lamp. This is to simulate tortoise height. Then get a digital thermometer and put it on the brick directly under the heat lamp. Let it cook for a couple of hours. How hot is it? Should be around 95-100 F, 37 C.