[QDanT]

Setting up a new tank I put the bag of Marine gravel in a bucket covered it with RO water and stired it around it went milky poured the water off and covered it with RO water again stired again milky poured water away and repeated this 5 or 6 times it still wasn't clear, at this rate I'd use up my 25ltr of RO water.
So plan B, I put the bucket under the kitchen sink cold tap on high and let it run for a couple of hours stirring now and again

gravel 2.jpg

untill it looked clear

gravel 3.jpg

gave it a stir Cloudy !

gravel 4.jpg

Took the gravel out bit at a time into a stainless steel kitchen sive and poured RO water through it then into x2 containers and covered with RO water and left over night next morning still not clear.

gravel 1.jpg

I think I'll give over to it and try some other substrate, it's as though something is dissolving out maybe Calcium ?

[odin]

Do you have a link or a photo of the gravel you used?

[QDanT]

here you are

Gravel.jpg

[odin]

If you have the time try constantly swirling it under the tap like you were before if it doesn't freeze your arm and hand lol, if you still don't get clear water you could try a different type like you suggested.

[QDanT]

I had thought of putting it in a large stainless steel pan and boiling it ? then wash/soak with RO water

[odin]

You could do, i've never known a substrate to take so much washing before... ive used Caribsea substrates in the past and they were pretty good so thats one brand to look at if you do wish to change.

[QDanT]

I gave it another hour under the cold tap still cloudy, put some in a stainless steel pan and covered with RO water then boiled for 5 minutes cloudy with a ring of scum round the lip, which had to be scoured off, sived the gravel under the tap put in a container topped up with RO water left over night you guessed right, still cloudy in the morning tipped it all on the garden and raided the wife's greenhouse for some topping off gravel some in a bucket filled with water stirred poured of and again, this time crystal clear rinsed it in RO water and put it in the tank - Phew !

Coarse grit.jpg

[odin]

Good call, i guess its just unlucky but dont let it put you off lol.