The tank is a low tech setup and I want to keep it that way since its at work and I can spend too much time on it. I'm doing 30% water changes weekly so I'm hoping that will be good enough to keep things clean enough. Should I be doing water changes twice a week?
I can't honestly comment on if 30% WC is going to be sufficient. I'd guess so, but the only real way to tell is to do a nitrate test at the end of the week BEFORE a water change. If the nitrate levels is below 10 PPM, then a 30% WC should be fine. But if the nitrate levels is higher than 10 PPM, then a 30% WC probably wouldn't be enough.
Then right after the WC is completed, do a second nitrate test to see what the difference is. Do this for a couple of weeks and see where the nitrates are at. That's the only real way to know. I always aimed for nitrate levels of 5 PPM or less for CRS.
I'm also dosing a 1/4 ML of excel about 3 time a week. I've read horror stories about excel and shrimp, but I think that's a low enough dose for a 2 1/2 gallon. I want the plants to fill in a bit more.
I used to dose with Excel too, and the CRS bred, and the shrimplets did just fine. But I made sure to dose at half the recommended strength. When I did though, the shrimp went crazy, just like they did when they smelled food. But if shrimplets survive and breed, then I don't see why it would be a problem.