water change question

[DKoKoMan]

I started with monthly water changes in my 75g. My phosphates got very high so I have been doing 20% water changes every 3 days for a while. Everything is back in check so I am planning on doing biweekly water changes. I hope this is able to maintain everything as I have a high bioload. I may end up doing weekly WC's if I have to. I'm thinking the monthly WC may be to long for me, but I May try this first before bi-weekly.