mr pink floyd

New member
i have a 29 tank upo for over 1.5 years, changed CC to sand 2 weeks ago, have fairly bad diatoms, weekly 5 gallon changes, how long will they last, will they ever go away?
You could be experiencing a new cycle since the tank is adjusting. Have you tested your water parameters?

That would be my guess. If so, they are likely to subside before too long on their own, but keep up with the water quality and test regularly.