LOL I have you know i have left that world for a better diatom-free one
yes I had diatoms for months with my T5's and here is what solved the problem:
1) RO/DI water - priceless, it has to be DI as well.
2) PO4/SiO2 remover from kent
3) better water circulation
Now they are fine, sit tight and they will go.
Tim.