Newbie Need Help On Green Water, newbie need help on green water Options

[gold2dee]

Hello, i have tried out green water using a 150W MH cool daylight bulb for the past 3 mths. I have only 3 goldfish of average size 7cm (body length). They are in a large blue guppy tub. The total amt of water the tub holds is ~170L

I am amazed by the growth and color improvement for the past 2 mths. However, for the past 1 mth, the goldfish seems to deterioriate in health. I see blood streaks in their tail and tail ends seems to tear.

I manage to cure them and re-started the green water but the syptoms always come back within 2 weeks after the water turns green.

If i seed back 10-15% of green water, i realise that on the 2nd day, ammonia is present and will only disappear by the third or fourth day. So i seed back 20%-25% instead and my green water turns dark green in just 2 days time. So every 2 days have to change 80% of water. Shiong ah.

Am i overloading the tub? Or anything i have done wrong? The MH light is switched on for 10 hours and sodium bicarbonate is added to up the KH to about 4dH. And i have cut down feeding those GFs to twice a day only.

Hope some kind soul can give me some pointers. Thank you very much and sorry for the long description.

[OhaiYo]

Only thing I can advise is lower down the timing of MH light. You already have existing green water to seed, so it shouldnt be the problem for green water to resurface again. If u find that green water is growing tremendously, try swithing off one side of the MH light bulb and tan with the other bulb..Hope this helps...My 2 cents