water has stuff floating

Question
hello my name is Melvin i have a 210 gallon fish tank. i change the water 30% or so every week or twice depending on how dirty water is i have 5 koi 1 at 11inc 3 at 8-10inc 1 marble catfish 2 1small algae 1 large algae eater 2 small gold fish i have this vary small white stuff floating and i talked with with all the pets shops around me the all say different stuff like over feeding but i only feed my fish 2 time a day before i go to work and when i come back i feed them sakari food about 1/4 of a cup 3mins in eating time or so i have sand only one live plant and i have a fx5 filter soon to get one more temperature is at 75 degrees i also have a maxi get 1200 on it PH is at 6.7  no ammonia that i can read i have no clue. tank you

Answer
Hi Melvin;

Your tank probably just needs more surface agitation. If you could get an airpump and run an airstone in there it will go away. Just be sure the pump you get is strong enough to work in your tank. I have had this problem too and it was solved very quickly with bubbles. They look cool too. ;-)

At Your Service;
Chris Robbins