Bubbles after changing to Dennerle gravel

[tropical-fish]

I have recently changed my substrate to DENNERLE crystal quartz gravel (Diamond black). I gave the gravel a good wash before putting in into the tank. the water is clear but when i turn on the airstone i get a blanket of bubbles on the surface of the water. when i turn off the airstone it takes about 1 minute for all the bubbles to burst and the surface of the tank is back to normal again.


anyone experienced this before with Dennerle gravel?

 

[tropical-fish]

today i did a 50% water change and it's a bit better now. still has bubbles but not as many. guess the problem will be solved after a few more large water changes. at least all of the fish are still alive and appear healthy.

i've turned off the airstone for the time being.