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Water Changes - Adding in water


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On 3/4/2022 at 8:53 AM, dasaltemelosguy said:

No problem @Wrencher_Scott. Those bulbs are rated for 5000 hours of a germicidal level of radiation, but most will do double that.

What I think is important is the life in hours, the wattage and if available, the radiation output in Joules which should be between 16uJ-33uJ. The reason fluorescing from a 2' distance in free air will tell you its working is that UV loses 75% of its power every time you double the distance from the bulb. If you equate that to the power it has just cm's close to the water, it's actually twice the level of UV required to kill bacteria. 

But I do understand that you'd like a bit more precision than making detergent glow in the dark! 

To that end, they make these really cool UV test strips.

You simply hold it 1" from the UV bulb and it changes color ONLY if there's a germicidal level of UV radiation present. They are cheap and you may buy them in bulk and verify your UV light has bacteria killing UV output as often as you wish:

UV Test Strip-1

This is another one with more graduations:

UV Test Strip-Meter

Here's a short video of someone using the UVC test strip above with a portable UV sterilizer:

This is a good chart to show how long it takes to kill various pathogens. "Shielding", the UV industry's term for shadows blocking UV light is one cause of imperfect sterilization. But what's most apparent here is that UV would require more time than flowing water would allow to kill eggs, so they pass right through anyway. 



I don't know the UVC output of the GKM but if it really kills algae in real time, it's pretty powerful as if you look at the chart, algae are by far the most difficult to negate via UV!

I hope this helps. Good luck. 

Yes, thanks! That gives me confidence in the GKM for sure.

But.... What about the unit to use and the bulbs to buy for them? Can you recommend a good brand of unit and a good brand of bulb? Also, where to buy the bulbs? I don't trust Amazon for this stuff because they sell counterfeit stuff all the time. 


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On 3/5/2022 at 1:28 PM, Streetwise said:

I feel really lucky that the chlorine treatment in my water district is so minimal, that I don’t have to worry at all. I fill my buckets from the tub, and I only off-gas if I smell any chlorine. Otherwise, I just let buckets sit to hit room temperature.

Same here. I only have to leave it sit over night.

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On 3/5/2022 at 2:15 PM, Bev C said:

 After filling the tank i add more prime for the whole tank again since the water sat out 24-48 hours with the old prime dose  Seachem says prime last for48 hours before you need to dose again 

Just FYI, you DO NOT have to re dose the Prime. It's job is done after the first dose. Those directions are there for their claim for "detoxifying ammonia" whatever that means. Many believe and it has been tested it does not do anything to ammonia anyway.  

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