Finally got a UV BUT !!!

[Bad Inferno]

OK after 2 years I finally got a UV. 11 watt phillips tube (Vorton 9000) which I thought for 180 litre tank should be overkill. Using Ehiem 2215 and have left it on 24hrs / day

The UV has improved tank clarity to "crystal clear" (however before the UV was installed you would of also thought it was very clear).

What I am troubled with is algea growing within my return lines. The UV is on the canister return into the tank and after about 3 weeks of operation algea is growing within the return line. (green dots). The tank is not in sunlight and am very surprised that if UV is supposed to kill free floating algea why has my new return line got algea ?

[weird]

I have brown algae growing in my 3 foot , which has had the UV on 24 hours ... for last 4 weeks. I am surprised as well. I am adding in some bristlenose in a week so not too concerned, but was surprised with the algae growing. I must have misunderstood - must be water clarity only.

[Proteus]

It will only kill free floating algae...

the algae you are referring to is a result of excessive or incorrect lighting (wrong spectrum/lumens) and phosphate/nutrient levels.

if all other areas such as lighting and water chemistry are correct, with the UV helping you will find that you will never see algae again... (well very little if any at all).

[Bad Inferno]

I have "to date"read good stories of UV. I understand the in-tank algea will not be killed and algea on glass will spread.

However I am talking about the "new" 19mm tubing I installed from the outlet of the UV into the tank. The UV unit and tubing is within a cabinet (ie dark) and tubing goes up the back of the tank.

I just assumed the outlet tubing of a UV would be the cleanest part of my tank.

[Proteus]

all water has sediment/nutrients in it...

point in question... cut open a regular garden hose (on the insode it is totally sheilded from light) you will find that it has a fine layer of slime...

hook a clear hose to a tap and leave it on for a few days and it will do the same... (whether it is dark or light)

sediment, nutrients, etc, cant be avoided... even the best filtration and mega wattage UV's cant stop milli micron sized particles of gunk...

also, what you may think is bad, could just be the good guys you want... Bacteria, aka, bio-bugs...

:wink: