I am in process of placing large order online, but I hav't hit send yet, and may wait until Wed. to get double vip coupons.

I have chosen an Aqua Medic UV sterilizer 9 watts for $64.99.
It describes it as for up to 100 gallon tanks.

This is for a 55 gallon tank, which I am upgrading lighting on.

Is this what I need, is it a decent price?
I have never had a UV before, so all suggestions welcome.

Can I expect it to keep all algea away or just certain kinds? Does does it keep most parasites away?
I am not having problems with algea at the present time, but with the advanced lighting I think I might so just decided to go ahead and order this at the same time as the lights.

Thanks

The price doesn't look bad, but if you want to keep your tank free of parasites I'd suggest getting at least a 18 watt sterilizer rather than a 9 watt.

IMO you need a turnover rate that's more than once an hour to control parasites. Most 9 watt UV units will not kill parasites if the flow rate is much higher than 55 GPH.

The only algae that a UV sterilizer will kill are free floating algae. A UV will not do anything for any algae that's growing on the walls or decoration in your aquarium.

Thanks Bak2it, and you gave me info which leads to mopre questions.

Although my tank is a 55 gallon, I have 2----350 penguin filters on there , so the flow rate would be 700 gallon per hour. Does the watt of the UV depend on the flow rate of the water, rather than the gallons of water in the tank?
Do you think even an 18 watt would be sufficient with the 700 flow rate?

Lets look at it a different way....

You need to have the water from the tank be exposed to the UV of the light for a length of time to kill what ever is in the water. Algae is killed quite easily - in a very short amount of time under the UV. Bacteria and parasites are a bit harder and require a longer "dwell time" under the UV light.

So you need to have the water move through the UV unit slowly enough that the water stays under the light about 7 seconds (I think that is right - I should look it up to be sure) to kill the majority of bacteria and parasites. If you have a small unit, and you turn it down so the water passes through slowly enough to sanitize the water, you will not turn over very much of the tank's water every hour.

If you have a larger tank - a 55 is a nice size tank - you will want to turn over about 55 gallons an hour, at least, through the UV unit. I do nont know if the smaller ones have the volume capacity to allow the water the proper dwell time and still be able to pump that much water every hour.

I put a Turbo Twist 6X on one of my 55 tanks and it works fairly well. I ran various tests - measuring the amount of water I have moving through it so I can adjust the flow rate to what I need it to be for parasites. It is OK powered - I would have liked a bit different unit if I had to choose again.

Nana6, You won't be able to use your Penguin filters to power a UV sterilizer. A UV sterilizer requires either a canister filter or a separate pump to push the water through the UV sterilizer. Toothless has a pinned topic in this forum that shows how to hookup a UV sterilizer.
http://www.kokosgoldfish.invisionzone.com/...showtopic=34785

Both wattage and flow determine how effective a UV sterilizer will be. Basically, it boils down to how much UV light, and how long the water is in contact with the UV light. The longer that the water is in contact with the UV light the more nasties are killed by the UV light. So the more wattage a UV unit puts out, the higher the GPH flow rate can past through the unit and still be effective.

So for example: A common 9 watt UV sterilizer running at 55GPH will kill parasites. But if that sterilizer is running on a 55 gallon tank, the water in the tank will only go through the sterilizer once an hour. Algae, bacteria and some parasites can multiply that fast, so you'll never be able to eradicate the nasties living in your tank. And to make matters worse... Not all of the water in your tank will go through the sterilizer each hour.

So how is this problem solved... By increasing the wattage of the UV sterilizer. As I stated earlier, the more UV light the faster you can run the water through the UV sterilizer. A good rule of thumb for common UV sterilizers is double the wattage and you can double the flow.

OK so how does this convert into what size unit should you get for a tank. From what I've read, the minimum turnover rate should be 1X - 2X per hour through the UV sterilizer. I personally don't think this is enough and recommend 3X -5X per hour. The 57 watt Aqua UV sterilizer in my 90 gallon tank is running at 10X per hour, and there isn't ANYTHING living in my tank water except fish.

Now let's talk about how much UV light is required to kill the nasties that live in our tanks. The size of the nasty that you want to eradicate determines how much UV light is needed. The bigger the nastie... The more UV light it takes to kill it. UV exposure is equal to [uWs/cm(squared)]. Don't worry about what this stands for, all we need to know is how many of these units are required to kill the nasties in an aquarium. Common Bacteria are killed by 15,000 units, Waterborne Algae are done in by 22,000 units, Most Parasites bite the dust at 45,000 units and Protozoa need a whopping 90,000 units or more.

When you're shopping for a UV sterilizer try to find out what the gallons per hour (GPH) flow rate is needed by the UV sterilizer to equal the amount of UV light to kill the nasties you're buying the UV sterilizer to eliminate. And then choose a UV sterilizer of enough watts that you to run the total volume of the water in your tank through the sterilizer at least twice an hour.

Thanks Daryl and Bak2it----great info there.
Bak2it---I realized shortly after I posted that, that I wasn't going to be able to run a UV with the Penguins----duh, I was on some strong pain meds that day. ha

I just now ordered my lights---see my other post, and decided not to order the UV at this time. Really need to wait and see, as, now I am considering perhaps possibility of canister filter for that tank.

Decisions, decisions, but I will get there eventually.