it looks like your play sand is starting to cause diatom issues despite you doing a little test area. the silica in that is going to become a problem. i would remove it all, followed by a few larger water changes this week while you still have a chance.
if you are going to use sand in the aquarium hobby make sure it is reef friendly. while it may seem in the beginning stages like its going to work fine, problems like leaching happen over time and once it takes over the tank there will be no recovering from it. there is literally a million resources online that suggest silica based sand is not for use in the aquarium hobby.
|