Help!!! My water is clouding up!

[happydanio123]

Hi everybody! Today when I filled my 20 litre aquarium up with water, it began to cloud yellow. I used a mixture of AZOO 4-in-one filter ceramic rings (which was recommended by the shopkeeper for this porpose), fine gravel (definately no bigger than 1mm), and a bag of Dennerle nutrient medium for mini-aquaria ready-to-use mixture (that was suited for 20 litres) followed by another sandwich of fine gravel. I placed some hardscape like pre-washed, aquarium safe rocks and pebbles into the aquarium and filled it up with tap water and dechlorinator using a hose from my tap. When I flicked on my flourescent lights, I found out to my horror that the entire water was stained yellow.
Please note that this aquarium has been used before but I scrubbed the glass clean of algae and boiled the substrate and decorations before putting it in. I also added my previous fish in as I have no other aquarium to put them in. Is it normal for such things to occur? Must I wait a few days for the "yellowness" to set? Will my fish be harmed? Any advice would be greatly appreciated! Thanks!
Postscript: Below is the attached photograph

[Dscheng]

It normal la. On your filter, it will go away.

[Suzerolt]

Monitor it for a couple of days. It may go away with filtration.
Else, more regular water change will help 'renew' clear water.
Alternatively, Seachem Purigen is something folks use to clarify water. Google "Seachem Purigen remove yellow"

I'm not sure of the cause. Maybe from 'boiling' the substrate?

[happydanio123]

Thanks for the constructive comments!

[Urban Aquaria]

The yellowish tint is most likely from the dennerle nutrient medium releasing tannins and organic compounds, such tinting will usually be cleared up after repeated water changes or if you use adsorption media (ie. carbon/purigen) in the filter.

Note that if you see such tinting in the tank, it could also indicate high levels of organics being released into the water column, which may comprise of ammonia and other nutrients, so it'll be a good idea to test the water parameters just to make sure that its still at safe levels for the livestock.