i recently bought a pair of bettas male/female im having trouble with dirty water. i want to breed them, but by the time the male builds the nest the water needs to be changed.  Filters are not good for bettas b/c i have heard that they can deystroy the nest and the bettas are keen to filters. so how cna i do this. i tried ot use a pump to get rid of the excrement but that is really horrible and it dont work really well. any advice?