[kiky]

All this time, I used to put UV lights in the last chamber. But since I have some head lost, I positioned it at some distance above water level to prevent being submerged in case of power failure. However, I think this reduces its efficiency.

So, now I tried moving it to the 1st/primary vortex, where I can place it closer to the water level. But after only 3 days, my kois are more lethargic and loose appetite. Is there a connection? Water parameters are ok, except that it is quite greenish with algae.

Technically speaking, where is the best place to put UV lights?

All comments would be greatly appreciated.