Running smaller UV sterilizers in series?

Beau_B · Jun 21, 2020

I have a 15w Aqua UV; I'm happy with the results for clarity and dino control. While planning a tank upgrade, I'm thinking I could add another 15w in series. Would be more cost effective versus selling what I have and buying a 25 or 40. As a bonus it would be a more compact arrangement...

In theory I don't see the issue. It would be similar to how the very large systems are set up.

AZMSGT · Jun 21, 2020

You can chain UV systems together with no issues. There are some very high end UVs that are designed this way. However make sure you have enough contact time for the size of your planned system.

Basically, the one in the link below is as you describe. The water flow is in a U.
https://www.bulkreefsupply.com/80-watt-classic-uv-sterilizer-black-body-aqua-ultraviolet-2.html

Beau_B · Jun 21, 2020

Thanks for confirming.

I'm currently using the 15w on 50g (actual) at about 400gph.

If I'm following the Aqua UV chart correctly, a 25w is spec'd for upto 150g, and thus 30w (15x2) ought to cover the same and be sufficient for my plans. I would be aiming for the same 30,000-45,000 and thus need 1200-800gph.

Suggestions/corrections welcome.

dwest · Jun 21, 2020

Beau_B said:
Thanks for confirming.

I'm currently using the 15w on 50g (actual) at about 400gph.

If I'm following the Aqua UV chart correctly, a 25w is spec'd for upto 150g, and thus 30w (15x2) ought to cover the same and be sufficient for my plans. I would be aiming for the same 30,000-45,000 and thus need 1200-800gph.

Suggestions/corrections welcome.

Agree that you can run them in series. But, from my personal experience and from lots of personal communications, you will want about 1 watt of UV per every 3 gallons of water for dino eradication. You will also want to run it much slower than manufacturers recommendations. It seems that about 2-3 tank volumes per hour is the sweet spot, run from DT back to DT. Also, even though the upfront cost is higher, you might want to look at an upsized unit as opposed to 2 as double the bulb replacements every year or so will change the total cost. My 57 watt aqua uv is very compact.

Vette67 · Jun 21, 2020

The other consideration is the efficiency of flow. Adding 2 in series is going to restrict flow twice as much as going through one unit. So if you have to buy a more powerful pump to accommodate for the extra 90 degree bends in the 2 units, have you really saved money?

Not saying you should do things one way or the other, just that you should consider the flow loss in the equation as well as the effectiveness of the combined wattages.