if you arent able to feed them at night for any reason (perhaps you go out for a night on the town a few nights a week? haha) they will usualy open up when you feed the tank also. just the scent in the water makes their feeders open.
also, one more comment about liquid foods and dts and such: i dont feed any of it because IMO, it is all a wast of money. i dont have anything that depends on phyto, but i do know some people who dose it to their tanks because they have zoos and mushrooms.... but let's be reasonable... a tablespoon of dts is going to be extremely diluted throughout ANY sized tank. so the changes that zoos or anythign else, which although most water, such in and take out water so slowly it could barely make a diffference before your skimmer removes it. also, look at how much y;oru skimmer removes. do you really want to/think you need to add more? just my opinion on the subject. but of course, there are a lot of things (such as your sponge) which DOES need it.
also, one more comment about liquid foods and dts and such: i dont feed any of it because IMO, it is all a wast of money. i dont have anything that depends on phyto, but i do know some people who dose it to their tanks because they have zoos and mushrooms.... but let's be reasonable... a tablespoon of dts is going to be extremely diluted throughout ANY sized tank. so the changes that zoos or anythign else, which although most water, such in and take out water so slowly it could barely make a diffference before your skimmer removes it. also, look at how much y;oru skimmer removes. do you really want to/think you need to add more? just my opinion on the subject. but of course, there are a lot of things (such as your sponge) which DOES need it.
