Weird yellow tinted water in test system

[Sprae]

As some of you may know, I've set aside my new Eheim 2213 inline with a new chiller cycling through a 25L bucket of water. I'm awaiting a few other things to come before I can hook up into my tank so I thought might as well use this time to cycle the new media. Note that the cannister only has 50% media as I've set aside space for old media to go in. Media is Substrate Pro and matrix with the standard blue sponge. I've also got an airstone to help the media cycling. Water used is tap treated prime.

It's been over a couple of weeks and the water recent started to become light yellowish. I did a 50% WC the other day and cleared it up for a day before it came back again today.

Is this normal? I'm thinking bacterial bloom? There's no IAL or plants in the bucket either.

[Dean]

Very strange mate. If it not under lights I would doubt it's algae or bacteria. Could be wrong though!

One of the kids didn't do we we in there ;)

[Sprae]

Heh. The setup is in the garage so my kid have no chance of messing with it.

No lights whatsoever. But would that be the issue?