Question
it is an out door fish pond- 3feet by 3 feet and 2feet deep. I have 2 pond sharks, 2 carps and about 30 guppies and molly's. I have water hyacinth plants in the pond.
q1- should the filter be on 24 hrs/7?
q2- why does the water get completely green in 3 days after cleaning the pond thoroughly?
q3- how often should i feed the fish? how much?
q4- i bought my carps and shark babies when they were babies but why are they so so scared to come up to the surface?
q5- the filter does catch the gunk but i don't think its enough! the ponds still turning a lovely emerald green but i dont want that! what do i do?

Answer
Q1 ) The filter is sized according to the flowrate and velocity. Or the turnover rate, it is the time taken by the pump to pass entire water through the filter. If the turnover rate is more than the filter has to run more hours.If it designed for less hour then you do not need to run 24hrs/7.
But the filter initial cost goes up with less turnover rate. Hence smaller filter is put in order.Hence you have to run 24hrs.Solution could be to put one more filter.
Q2 ) Any water exposed to sunlight will turn green, since sunlight and water is breeding ground for algae, it has to be killed. Option for fish pond would be to use UV depending on the flow rate of the pump,but again the filter turnover should be adequate.
Q 3) It depends on number of factors which is difficult to answer. With the information provided
Q4 )Difficult to answer with the information provided.
Q5 ) Change the filter to bigger size and accordingly size the UV. This will take care of the problem.