UV Sterilizer

[kmayhew01]

My boyfriend just bought me a 5 W UV Sterilizer for my 40 gallon planted tank. My question is, should I run it all the time or only at night or what should I do? I have heard something about how it will diminish all of the nutrients my plants need in the aquarium. I would be grateful for any advice

 

[TankGirl]

If you are not having any problems with the tank I'd hold onto it until you find it necessary. The bulbs are expensive and it is a pain to maintain the sleeve, etc., so if you don't have a reason to run it I'd save it for when you need it.

 

[wobbles]

Try gravel ferts. Seems to be working for me

 

[kmayhew01]

Well, I feel that I really need it because my algae is out of control. I even have the light set so its not on all day, there are periodical nap times. I am also concerned about possible parasites.

 

[malkore]

Well, algae gets out of control due to nutrient imbalances. What are your nitrate and phosphates sitting at?
40gallon tank with how much lighting?
CO2 injection? if so, what's the level?

UV will kill algae spores, but not the algae that already exists. You're trying to use a band-aid when what you need is to know the cause, so we can choose a proper solution.

 

[Zezmo]

I use a UV sterilizer on my planted tank (8 watt/twist). I run it all the time with out an issue of it "neutralizing" my ferts that I can tell. I have read that if you run it 23 hours a day or less, you will get longer bulb life. I would say, since you already have the UV. You might as well hook it up and run it most of the time. Like maybe 20-23 hours a day on a timer. If you are still concerned about ferts, add a little extra iron, or trace mix.

 

[malkore]

UV's only oxidize certain trace minerals. They wouldn't affect the NPK ferts.
And what it does remove isn't a crazy amount..a slight increase in frequency of dosing your trace mix would make up for it easily.

 

[kmayhew01]

My nitrates are at 20 ppm, i dont know about my phosphate level. I have a T5 lighting system on my tank thats 36 W and a plant bulb that gives out maybe 20 or 30 W. I have a hagen CO2 injector that is for a 20 gallon tank.

 

[Wizzard~Of~Ozz]

Plant bulb, I've had nothing but problems with them, typically they are pinkish in colour, around 2700kelvin and cause greenwater all the time IME.

Try leaving the "plant bulb" off if it is under 5000kelvin, or replace it with a 6500-6700k bulb and leave the algea growing bulb in the closet.

The red spectrum they put off, unless run with an actinic to give the plants the needed blue spectrum, cause a deficiency in blue's allowing algae to flourish while the plants can't absorb the light properly due to the lack of blue spectrum with respect to the abundance of red (remember, algae can thrive with a deficiency, plants require all things to be met and be relatively in balance.)

at least that is my experiece.

 

[kmayhew01]

My T5 light has a 21 watt true actinic 03 blue and a 21 watt 10,000K Daylight in it. I know that plants absorb both red and blue which is why I went ahead and got the plant bulb that has the red.

 

[Zezmo]

Visible Color or color temperature (Kelvin Rating) which is how a bulb looks to the human eye. Is not directly related, nor often even a good indicator of "spectral output" as required from the plants perspective.

 

[kmayhew01]

So, should I use my UV Sterilizer or not or only sometimes?

 

[Zezmo]

well, my vote would be since you already have it.... you should use it.

At the least it will do nothing, at the most it will help control algae, and prevent disease in your fish. Any concerns over "destroying" your micro nutrients are easily countered with dosing a little more often.

 

[kmayhew01]

How often do you think I should dose if I run it?

 

[Zezmo]

Dosing ferts is really a whole different discussion. I personally only add a bit of extra iron. I add my Flourish like normal, and add an extra half teaspoon of Flourish Iron. I am dosing these micros about 3 times a week.
That said, I don't believe that low wattage UV, like your 5 watt or my 8 watt is going to have any noticeable effect on micros. Maybe if you had a big 25 watt or larger one it would be a concern.
You do mention algae. That suggests nutrient imbalance/deficiency, lack/excess light, or CO2 problems. It is doubtful that this U/V will make the algae go away. There is a lot of good anti algae type information found on these boards if you search about some.

 

[TankGirl]

I may have faulty memory, but I thought I read somewhere once that UV sterilizers rendered Flourish Excel ineffective. This may or may not be true - I have no clue. Could this be where the question of dosing ferts with a UV sterilizer comes from?

 

[Simpte]

The 10000K bulb is fine. Many (including myself) use them in conjunction with other bulbs (6500-8800K). The 03 bulb isn't helping much. I would replace it with a 6500-6700K bulb. (T5 do not have the same spectrums available as no or pc bulbs right now).