Filter Choice of my tank causing color change???

I had my axie, Joanna for a few weeks now, she's in a 40l tank with sand and I feed her bloodworm, brine shrimp, bits of meat or liver, a mix really. Anyway, she went in the tank after it was drained after my newt decided to escape the day before intending to get a few more newts from the pet shop. Anyway, now I have Joanna instead and she had a large amount of ammonia in the tank that was severely dangerous, the piddly filter that kept the newt and fish clean couldnt cope, I went to the pet shop and they recommented either a fluval U series submerged filter or the 105 cannister filter. I decided on the 105 cannister as it would allow more room in the tank and it wouldnt be vibrating in the water like the submerged one, with a huge capacity for filtering as well I thought it was a good choice and the shop staff told me the flow rate 'shouldnt' be too stressful for her, it certainly dosen't seem as stong as the Stingray filter I once had. Anyway she's had this cannister filter installed for a few days and I think I'm noticing a colour change in her (she's wild type), going more pale from the bottom up, I read some of the other threads on colour change and the general concensus seems to be that its normally genetic and harmless. But I thought I'd ask what other more experienced keepers have used or had experience with my model of filter and whether it's likely a problem for her. I hope its not stressing her, maybe it's change in water quality??

Thanks.

What's the water flow like with a canister filter like that? That's a fairly small tank so I'd be worried about a canister filter providing a bit too much current.

I think it may be a little too turbulent, It does 430l/h. I'm thinking of trying to find a spraybar to stick on it to spread it more, it the moment its coming in through one end of the tank.

That could be your problem!

The fluval 105 has a lever that you can use to decrease the flow rate (see manual). Until you get a spray bar set up, I'd recommend cutting the flow rate down.

reading around, I get the impression that filter flow for axie tanks should be no more than twice the tank size per hour, 430L/Hr on a 40L tank is an almost 11 times the tank size flow rate.

Thanks Jennewt, I'll have a look through my manual now!