I need some input

Well I have two things, first and foremost I added to many fish to quickly to my tank and now have an ammo problem... Test showed .50 ppm this morning so I did a 20% WC which dropped it back down but it's going back up. I have recently added 2 clown fish ( I heard adding them in pairs was important) and a cool little fire shrimp. This is what was in there before the clown fish and fire shrimp, I have a colony of Zoas, 1 damsel, 1 cleaner shrimp, 6 hermit crabs. Also I got some kind of sea star which is missing limbs possibly from some recently added live rock. My tank has recently fully cycled it's a 14 G Biocube, with skimmer and bio balls ( I've decided to keep the bioballs too). My plan is to take out the shrimp and clown fish and hope that the rest of the livestock make it through the mess I caused. I am kicking myself as I write this, one issue I have though is I don't have another tank to place them in temporarily. I do have a 2 G bucket(used for WC) and a small isolation tank probably about 1/2 G, I can't afford another tank right now. So do you think those would be able support the fish, that I can isolate while my mess gets sorted out?

Secondly, has anyone used Berkey water filters for their salt water mixes. I have a berkey filter I use for my drinking water. I hear it's about equal to RO probably not as good as RO/DI though. I've been using saltwater from my local store, but would like to start mixing my own since it would be cheaper and easier for me.