hi tell. fillter wool was ok t start whith but after 3-4 days it i made the fx5s slow down to a trikle and it wernt packed in to tight. as for overflow box not to clear wat it is mate. also im ok whith drilling but it whould be a major task moving stok sand and all out . can lighting make a wide deep tank look cloudy?ive not had problems b4 whith tanks of 200 gal so im a bit baffeld to be honest as to why its such a problem all test are ok ph is the only diffrence 7.5-8 wer ass i usaly read it at closer t neutral