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treesprite

what flow rate 36w uv?

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It has been many years since I used a uv sterilizer, and I was only using it on QT tanks (it was only 9w). I want to see if using UV on this current system will have any benefit, so I bought an inexpensive one that is 36 watts. The total system volume is about 75 gallons.

 

Along with needing to know the best flow rate, I need to figure out which sump to put it in since those have different flow rates (I didn't have enough space for a bigger sump, so I have an arrangement of two smaller ones).

 

Sump #1 is a 15gH raised a little off the ground behind the tank.  It is a full tank of water. It has the main return pump in it which I think is rated 1200gph which feeds the DT with a Sea Swirl return. It overflows to Sump #2.

 

Sump #2 is inside of the stand. It is a half-filled 20gH which maintains a level of about 10g of water, contains the protein skimmer and ATO sensor. The #2 return pump goes back to Sump#1, and I think the pump is rated 500gph. I probably should use a smaller return pump but wasn't too concerned about it since the returning to the other sump (instead of display) makes me think it has a bit or a recirculating effect (maybe I have no clue what I'm talking about, so feel free to correct me if you think it will help me). 

 

Advice/suggestions are greatly appreciated.

 

 

 

Edited by treesprite

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See page 9 (12th page of the PDF) here for something from Aqua Ultraviolet for UV guidelines for saltwater/reef tanks.

 

Here's a snapshot of the page:

small.UV_Chart.png.aa133d3dbdc5a9dea2e79

 

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I just noticed that the suggested flow rates for AquaUV seem very high. I'm not sure why they have them so high.  DFS has a similar chart but with lower flow rates. 

 

small.UV_Chart2.png.d8d857106e9069cdfb76

 

SmartUV which BRS sells seems to have other (lower) numbers, even. Maybe the DFS numbers are a good compromise?

 

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As for location, I'd recommend that you put it in the return from Sump #1, but lower than sump itself so that you can configure it so that water is always in it (even if the return pump failed). That would help keep it from overheating should the pump fail.

 

Is the return pump in Sump #1 rated for 1200 gph considering head pressure, or is it rated at 1200 gph max? If the latter, then you're probably somewhere between the DFS numbers and the AquaUV numbers for bacteria/algae control if you put it in the Sump1 return.

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Thanks, Tom.

 

The 1200 is not including head pressure. It's straight up about 2 feet then into a Sea Swirl. The Sea Swirl probably takes a lot away because of the bend and the pipe size changes. The tank only has one hole in it, and when I got it, I wasn't up to drilling it, so I'm really limited.

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Well, I just now got home and the package was delivered at the door. They sent me an 18w sterilizer. I was certain I ordered the 36w, but according to the eBay thing, I paid for the 18w. Maybe I clicked the thing on the drop down option list. Is 18w going to work well for 75g of water? I could always replace the bulb in the old 9w one and use them both (I wonder if I could just connect them together if I use both).

Edited by treesprite

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So now I have found my pump box and it says it is rated 1022, and there is a chart for head loss, so it looks like I'm probably only getting 700gph from it. It is a Quiet One pump. I am wondering if the 950gph Aqua Mag pump I bought but didn't use, would perform better even though it has a lower gph rating. Of course I just now this very second remembered that I have a bigger Quiet One pump from my old tank just sitting in with tank junk.... wondering if I should switch to that one since I've apparently got so much lost flow.

Edited by treesprite

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The Sea Swirl will probably eat into your output.  I think that you'll be fine with 18W. Another option would be to put the UV in the return from Sump #2 to Sump #1. This would have less effect on how much water is going back to your display. (Adding a UV to this path would only add drag and therefore reduce flow into the display.) You'd have more recirculation but, over the long run, I think that you'll achieve what you're looking for. That may be a better option given the smaller pump size.

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I put it in the #1 sump with its own pump (tank tends to run cool, and I don't have electric bills to pay). The only place I could put it is on the end where the main return pump is, because the sump tank is wedged tight between the wall and the back of the tank stand and the other end of it is the end where the drain pipes and the overflow to #2 sump are.

 

I had to wait for delivery of a flow meter to put on it, so I didn't have it set up and running until about 10 minutes ago.  The smallest pump I had right on hand was a maxijet 1200, so I have a valve on the output and the flow meter is after the valve. I put an Eheim pre-filter on the intake so a bunch of gunk won't get in the sterilizer and meter. I figured I would be a little more serious with this sterilizer, so maybe it will actually do some good. I've got the flow rate at only 75, still need to do some more figuring for it.

 

Now that I have used a flow meter for the first time having never seen one in operation, I think it's a really helpful and cool device, so I might make myself believe I need one for my main plumbing. The idea has kind of made the subject of plumbing more exciting.

 

Edited by treesprite

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Heads up, Forrest: One more post and you'll join the 5-digit club - 10,000 posts since finding the community nearly 12 years ago.

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On 1/16/2019 at 10:46 PM, Origami said:

Heads up, Forrest: One more post and you'll join the 5-digit club - 10,000 posts since finding the community nearly 12 years ago.

OMG I had no idea! I guess this is it!

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Here's a little souvenir of the milestone:

 

large.Forrest_10K.png.89581fa37481b2fde3

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Lol. Thanks, Tom.

 

My water seemed to look clearer within just a few of days of running the sterilizer.

 

I have been feeling a lot lately like finally putting up the 120, but if I do, this sterilizer will be too small for it. I wonder if using this one and the 9 watt one together would work if I ever set up that big tank.

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7 hours ago, treesprite said:

I have been feeling a lot lately like finally putting up the 120, but if I do, this sterilizer will be too small for it. I wonder if using this one and the 9 watt one together would work if I ever set up that big tank.

If you're asking if you can daisy-chain them, my guess would be yes. The UV dose should be cumulative within a single pass, so long as you're controlling flow. As it is, your single 36W UV may be sufficient for a 120 on its own according to those tables above.

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