# UV Sterilizer Question



## Nevermore (Mar 26, 2007)

I began having a problem with cloudy water after I added CO2 to my 20 gallon tank. I've had it for a full week now; I guess if it's bacteria it'll resolve itself within 2 weeks. I am thinking ahead to possibly needing a uv sterilizer but, if I'm going to buy one, I want one that will be effective against parasites as well as algae. On Foster & Smith's website, they have a table seeming to show that you need 15 watts or more to kill parasites. http://www.drsfostersmith.com/pic/article.cfm?acatid=423&aid=440 Am I understanding this correctly? I've seen quite a few posts in which people are using 9 watt uv sterilizers and are finding it's helping to keep their fish disease-free. Do you base your choice of what size to buy by what you want to eliminate or by the size of your tank? I'm confused about which size to get for my 20 gallon tank.


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## iceblue (Dec 2, 2005)

Base it on the size of your tank. A 9w is rated for up to 125gal so it would be more than enough for your 20gal tank. You then control the flow of the water passing through the UV sterilizer depending on what you are treating the tank for. Higher flow rates are for bacteria, middle flow rates for algae and real low flow rates for parasites.
By the way what type of CO2 are you using? If you are using sugar-yeast make sure none of it is backing up into the tank itself.


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## Homer_Simpson (Apr 2, 2007)

Nevermore said:


> I began having a problem with cloudy water after I added CO2 to my 20 gallon tank. I've had it for a full week now; I guess if it's bacteria it'll resolve itself within 2 weeks. I am thinking ahead to possibly needing a uv sterilizer but, if I'm going to buy one, I want one that will be effective against parasites as well as algae. On Foster & Smith's website, they have a table seeming to show that you need 15 watts or more to kill parasites. http://www.drsfostersmith.com/pic/article.cfm?acatid=423&aid=440 Am I understanding this correctly? I've seen quite a few posts in which people are using 9 watt uv sterilizers and are finding it's helping to keep their fish disease-free. Do you base your choice of what size to buy by what you want to eliminate or by the size of your tank? I'm confused about which size to get for my 20 gallon tank.


Have you had your tank running for a week now or have you had the cloudy water for a week? If your tank is new, I would recommend against a UV sterilizer until your tank is fully cycled. UV sterilizers are known to interfere with the nitrogen cycle in newly established tanks. Specifically they will interfere with the establishment of beneficial bacterial colonies. The "good" bacteria will be killed off before it has a chance to fully settle on your filter media, glass, gravel, etc.,. Once the nitrogen cycle is complete and the colonies have established themselves firmly on surfaces, then the UV sterilizer is not known to kill them. Have you tested your water parameters? If your tank is still cycling, you can use "septo-bac"(http://www.crlca.com/fishsite/articles.html) to speed up cycling or just add a lot of "healty" plants(best option). You can also use a product like Seachem's clarity which will help quickly resolve the cloudy water issue without interfering with the nitrogen cycle. You just have to clean your filter more frequently if using clarity until the cloudy water resolves itself. This is an interesting article on what causes cloudy water. http://www.nunnie.com/cloudy.html

By the way, I have a 9watt UV sterilizer in my 20 gallon and 40 gallon. While I don't have microscopic proof, I believe that they have worked in keeping the water parasite free. If you inadvertently get a diseased fish from your lfs and place it in your tank, the UV sterilzer will not kill the parasite(s) already in that fish, and the diseased fish may still die. However, the UV sterilizer will kill the parasite when it becomes water borne and before it can infect your other fish. However, UV sterlizers are known to interfere with the absorption of iron and possibly other trace minerals needed for healthy plant growth, so It is really a trade off with respect to what you consider more important. Healthy plant growth without any nutrient deficiencies whatsoever or the need to protect all your fish from parasites that could be introduced into the tank from new fish infected with parasite(s). Some people set up a seperate small quarantine tank and observe/treat new diseased fish before introducing the fish into their regular tanks. I just find that to be too much of a hassle vs using a UV sterilizer.

Finally, keep in mind that there is an added cost of replacing UV sterilizer bulbs every 6 months. Apparently UV bulbs lose their effectiveness after 6 months and need to be replaced. Be sure to buy one that allows for this and compare prices for replacement bulbs for the different UV sterilizer brands.


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## vicpinto (Mar 27, 2007)

Nevermore said:


> I began having a problem with cloudy water after I added CO2 to my 20 gallon tank. I've had it for a full week now; I guess if it's bacteria it'll resolve itself within 2 weeks. I am thinking ahead to possibly needing a uv sterilizer but, if I'm going to buy one, I want one that will be effective against parasites as well as algae. On Foster & Smith's website, they have a table seeming to show that you need 15 watts or more to kill parasites. http://www.drsfostersmith.com/pic/article.cfm?acatid=423&aid=440 Am I understanding this correctly? I've seen quite a few posts in which people are using 9 watt uv sterilizers and are finding it's helping to keep their fish disease-free. Do you base your choice of what size to buy by what you want to eliminate or by the size of your tank? I'm confused about which size to get for my 20 gallon tank.


You have a choice of adjusting 2 parameters. Flow rate and wattage. You can kill parasites with a slower flow and lower wattage. You can also speed up the flow but then you also need to increase the wattage. That's what I did in my tank - 38G with a 25W UV. I have a XP3 with the outlet valve almost all the way open. According to the chart supplied by CurrentUSA and my flow rate meter, I'm still killing parasites.


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## mikenas102 (Feb 8, 2006)

Homer_Simpson said:


> However, the UV sterilizer will kill the parasite when it becomes water borne and before it can infect your other fish. However, UV sterlizers are known to interfere with the absorption of iron and possibly other trace minerals needed for healthy plant growth, so It is really a trade off with respect to what you consider more important..


I hear this all the time yet nobody has ever proven this theory. I've had a UV running on and off for over a year and a half. I turned it off one time for about a month and a half just to try to prove or disprove this assumption. There was absolutlely no change in the growth rate or health of my plants. Until somebody comes forward with scientific evidence of the "UV iron theories" I'm convinced it's all a bunch of crap.


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## houseofcards (Feb 16, 2005)

mikenas102 said:


> I hear this all the time yet nobody has ever proven this theory. I've had a UV running on and off for over a year and a half. I turned it off one time for about a month and a half just to try to prove or disprove this assumption. There was absolutlely no change in the growth rate or health of my plants. Until somebody comes forward with scientific evidence of the "UV iron theories" I'm convinced it's all a bunch of crap.


Well I'll top ya, I've had a UV running 24/7 for almost two years and I've yet to see a problem related to the UV. I did once speak to Seachem about the FE issue, but they something to the effect if you dose Iron often enough (which you should) there really is no issue. I believe Greg Watson also runs a UV 24/7. I do not run big flows on my tanks. I only turn over my water once or so an hour, so I've had great success killing both parasites and algae with a 9watt UV on my 72g.


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## Nevermore (Mar 26, 2007)

My tank is fully cycled and has been running fine for four months before I added the CO2. The CO2 is pressurized.

Do the portable uv units all allow you to adjust the flow rates? I'm thinking about getting a portable so I can use it on other tanks if necessary.


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## JamesC (Jul 26, 2005)

houseofcards said:


> Well I'll top ya, I've had a UV running 24/7 for almost two years and I've yet to see a problem related to the UV. I did once speak to Seachem about the FE issue, but they something to the effect if you dose Iron often enough (which you should) there really is no issue. I believe Greg Watson also runs a UV 24/7. I do not run big flows on my tanks. I only turn over my water once or so an hour, so I've had great success killing both parasites and algae with a 9watt UV on my 72g.


Must admit I've had a 11w UV on my 55 gallon for nearly three years now and never noticed any iron deficiency problems.

James


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## vicpinto (Mar 27, 2007)

No, not on the UV itself. Most canister filters have a way of controlling flow rate.


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## Homer_Simpson (Apr 2, 2007)

Interesting discussion. Given differences in peoples' experience re: whether or not the use of UV sterilizers causes iron deficiency problems makes this forum so interesting.

http://www.aquaticplantcentral.com/...tilizing/42109-last-battle-against-gsa-2.html

As with most things in life, I guess people have to experiment for themselves to see what happens


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## houseofcards (Feb 16, 2005)

For anyone interested here's my original thread in the Seachem forum where I asked about a UV and dosing Iron.

http://www.aquaticplantcentral.com/forumapc/seachem/14801-flourish-iron-uv.html


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## Nevermore (Mar 26, 2007)

houseofcards said:


> For anyone interested here's my original thread in the Seachem forum where I asked about a UV and dosing Iron.
> 
> http://www.aquaticplantcentral.com/forumapc/seachem/14801-flourish-iron-uv.html


That's good info, but I'm still trying to figure out which uv sterilizer to buy, my cloudy water shows no sign of letting up. I have a canister filter, to be able to adjust flow rate on my uv sterilizer do I have to buy an in-line model so I can plumb it to my filter? That's kind of bad because I'll need to cut my flow down on my filtration (if I want the uv sterilizer to eliminate parasites as well as algae). The portable models don't allow you to control flow rate?


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## Homer_Simpson (Apr 2, 2007)

Nevermore said:


> That's good info, but I'm still trying to figure out which uv sterilizer to buy, my cloudy water shows no sign of letting up. I have a canister filter, to be able to adjust flow rate on my uv sterilizer do I have to buy an in-line model so I can plumb it to my filter? That's kind of bad because I'll need to cut my flow down on my filtration (if I want the uv sterilizer to eliminate parasites as well as algae). The portable models don't allow you to control flow rate?


Have you considered one like this. Although it is portable, it allows you to adjust flow control and the bulb can be replaced. A 5 watt model should be more than enough for a 20 gallon aquarium and if you decide to use it in another aquarium it is portable. Rohape uses one like this and swears by it.
http://www.jbjlighting.com/sys_uv.html


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## Nevermore (Mar 26, 2007)

Homer_Simpson said:


> Have you considered one like this. Although it is portable, it allows you to adjust flow control and the bulb can be replaced. A 5 watt model should be more than enough for a 20 gallon aquarium and if you decide to use it in another aquarium it is portable. Rohape uses one like this and swears by it.
> http://www.jbjlighting.com/sys_uv.html


That looks ideal! Thanks!


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## Homer_Simpson (Apr 2, 2007)

Nevermore said:


> That looks ideal! Thanks!


You are welcome, but all credit for Rohape for posting the link. I plan to switch over to this one.

The one that I am using is this one: http://www.aa-aquarium.com/NewProduct2.php?id=156&line_id=&level=3

A LFS(not the one where I purchased it from) was selling one for $20(instead of the regular $80). I asked him why so cheap, and he told me that you could no longer get replacement parts for the item including bulbs, so they were on clearance.

Also, while it seems to work fine for me, this review would suggest otherwise:
http://www.aquaticplantcentral.com/forumapc/aquarium-equipment/8691-reviews-internal-uv-filter.html


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