DIY UV Sterilizer Project

bg2311

Well-Known Member
Supporting
Messages
297
Reaction score
285
Location
Marietta
Hello!

I'm starting a build thread for a DIY project that I'm working on (if this should be in another forum section, mods please let me know). The sheer cost of consumer/prosumer grade UV sterilizers was enough to motivate me to try to build my own.

Quick required safety disclaimer:
Even brief exposure to intense UV radiation is harmful to the eyes and skin as is high-current (wall voltage) electricity. Both will be utilized to some extent in this build as would any consumer grade UV sterilizer. While I have a modest amount of experience with plumbing at this point and past electrical projects I am by no means a professional and you should not attempt to do duplicate what you see here. Do your own research. Remember, safety third first. Please don't try this at home. </warning>

Goal:

With that out of the way, my goal here is to build a DIY UV sterilizer for our reef system (currently ~200 gallons total system volume between the 120g display and 80g frag tank) for well under the cost of a consumer/prosumer unit. Thus far that seems quite feasible.

Requirements:
From what I've gathered the target wavelength needed for the sterilizer to be most effective is ~254nm and this is readily available in the form of either LED strips or traditional fluorescent UV bulbs. I'm going with UV bulbs because they will be much easier to replace when needed. The UV light emitted needs to be fully shielded when operating for safety. Only the water should be exposed to it and will benefit from being in close proximity to the bulb. Quartz glass is the material of choice for UV at 254nm because it lets most of the desired wavelength through. I'm starting with a 55w UV bulb which given the proper contact time (flow rate/surface area of the quartz coil) should be enough to properly treat our 200g system. The cost of this build must be under the cost of a prosumer unit.

Design:
I'm going to try to flip the usual design inside out and put the water inside of the quartz instead of the bulb utilizing a lab grade quartz condensing coil like the one below, but properly sized to the length of the bulb in this application. At the moment I'm sourcing a custom prototype from Alibaba. This is likely to be the most expensive part of the project however we're still talking a fraction of what a properly sized off the shelf sterilizer would cost for a 200 gallon system.

Example quartz coil:

quartz coil example.jpg



The UV bulb:

uv bulb.jpg





The enclosure housing the bulb and coil will be lined with a roll of adhesive aluminum (one of the few things that reflects the desired 254nm wavelength) to maximize the exposure of the water to the light as it passes through the quartz coil from the bottom of the unit to the top (this should help any air bubbles escape). The plan is to have the coil mounted vertically. As for the wall thickness of the quartz coil, I'm thinking of starting with something over 1mm which seems to be the typical thickness of the quartz sleeves used in off the shelf units (perhaps 2-3mm) . Doing so will slightly reduce the overall transmission of the UV light but the tradeoff may be worth it for the added structural integrity of the coil to avoid breakage from internal water pressure, during shipping, and handling during maintenance (replacing the quartz coil). Being a closed loop this will not be designed to handle the full flow of the system through it from the start. I can easily up-size the quartz coil later if I desired if I want additional flow through it (might required a slightly thicker quartz coil wall).

Safety:
As a precaution I'm thinking of adding a Neptune Apex optical sensor at the bottom of the enclosure to quickly detect any liquid and shut off all power to the ballast and utility pump feeding the closed-loop unit should a leak occur. The bulb socket will be at the top of the unit so any drips are unlikely to make it to an electrical contact. There should be no moisture inside the enclosure at all (it all passes through the quartz tube that spirals around the bulb). The external enclosure is just to safely shield the UV light inside of the unit and hold the quartz coil/bulb in place. I might add a maintenance viewing port made of UV-safe viewing glass to confirm proper operation while the unit is closed/on while protecting my eyes. The high voltage UV bulb ballast will be up out of the way in a waterproof enclosure with a drip-loop plugged into a GFCI outlet.

Parts ordered so far:
Bulb: PLT pL-L55W/TUV 55 watt dual-lamp UV bulb which utilizes a 2G11 4-pin socket - $28
Socket for the bulb: 2G11 - $6
Vertical/horizontal clip-on supports for the bulb - $2
Ballast for the bulb: Advance Centium ICN-2S54-T (54w, 2 lamp ballast) - $22
Wiring (misc 120v solid core copper insulated wire)

Parts needed: (more to follow):
Enclosure for the bulb/quartz coil
Waterproof enclosure box for the UV bulb ballast
Roll of aluminum reflective sheeting for lining inside of enclosure
Quartz coiled tube ~20" long, 3/4" OD tube, ~ 2.5" across coil ID - cost TBD (sourcing from Alibaba)
3/4" grommets/silicone fittings to plumb in
3/4" quarter turn ball valve to adjust flow
GPH in-line flow meter for Apex


6/10/2021:
I'll try to add more to this post as parts arrive and I start to fit the prototype together. At the moment I'm getting quotes for quartz coils from Alibaba. This will be the most expensive part of the build but ordering in bulk makes them cheaper. If this is successful I plan to replace the quartz sleeve and bulb as would be done with any UV sterilizer after 6-12 months so I will need to order more of them once I get the size/glass strength correct for this application.

6/11/2021:
I have this build cross-posted to R2R for additional visibility. Someone brought up the possible need for heat dissipation for the UV bulb inside the enclosure. I'm hoping that the flowing water through the quartz sleeve will act as a heat exchanger, carrying water heated by the ambient air inside the unit away back to the tank as it passes through the tube and reducing the overall temperature inside the enclosure. I will need to monitor the ambient temperature inside. If passive cooling doesn't work, an active approach may be needed. I had the idea to perhaps use extruded aluminum motor housing like the example photo below:

extruded_aluminum_motor_housing.jpg

Aluminum is a great conductor for heat. It's been used in the past for external computer water cooling tower loops like the Zalman series below. Should additional cooling be needed this might be enough on it's own, or a fan could be added if necessary:

reserator.jpg





TLDR Disclaimer: Electricity and water don't mix. Radiation is bad for you, mkay. Don't try this at home.
 

Attachments

  • quartz coil example.jpg
    quartz coil example.jpg
    53.8 KB · Views: 27
Last edited:

bg2311

Well-Known Member
Supporting
Messages
297
Reaction score
285
Location
Marietta
Very interesting. But .. PICs!!!
Trying to get edit permission for this thread. In the mean time I'll add some photos as I go in the form of replies to the thread. First few parts should be arriving today. Still working on sourcing the right size quartz coil. Since I don't need 100 of them it's a matter of finding the right vendor.
 

bg2311

Well-Known Member
Supporting
Messages
297
Reaction score
285
Location
Marietta
Trying to get edit permission for this thread. In the mean time I'll add some photos as I go in the form of replies to the thread. First few parts should be arriving today. Still working on sourcing the right size quartz coil. Since I don't need 100 of them it's a matter of finding the right vendor.
I've got edit permissions for this thread now so I will try to update the OP to keep things tidy.
 

Adam

Treasurer
Staff member
Supporting
Messages
4,443
Reaction score
2,796
Location
Flowery Branch, GA
I'm very interested in following how things progress on this project. I am going to be in the market for a UV in the 100's of watts soon. I love DIY and saving money is nice too.

I don't know if this is fact or not but my take on the spiraled quartz tube is it will speed up the flow through the uv chamber. Less volume traveling through the same relative space. It is also going to be much harder to source than a standard quartz tube as well as being harder to clean. Maybe down right impossible to clean as the deposits will be on the inside of the spiral. Just my $0.02.
 

bg2311

Well-Known Member
Supporting
Messages
297
Reaction score
285
Location
Marietta
I'm very interested in following how things progress on this project. I am going to be in the market for a UV in the 100's of watts soon. I love DIY and saving money is nice too.

I don't know if this is fact or not but my take on the spiraled quartz tube is it will speed up the flow through the uv chamber. Less volume traveling through the same relative space. It is also going to be much harder to source than a standard quartz tube as well as being harder to clean. Maybe down right impossible to clean as the deposits will be on the inside of the spiral. Just my $0.02.
I'm trying to find a vendor source for the quartz tube with a decent number of coils, proper diameter etc. to get the exposure time to the UV light correct. May go with something premade on Alibaba vs. customizing it if I can find a product ready made that fits the bill and just adapt the enclosure to it. Chaining 2 smaller 10" coils of quartz together for instance might work if getting a custom one-off 20" coil proves to be too expensive. The sleeve won't be easy to clean so it needs to be cost effective enough to be replaced along with the bulb ($28) as needed. The more pieces you order, the cheaper they get usually.
 

bg2311

Well-Known Member
Supporting
Messages
297
Reaction score
285
Location
Marietta
I'm trying to find a vendor source for the quartz tube with a decent number of coils, proper diameter etc. to get the exposure time to the UV light correct. May go with something premade on Alibaba vs. customizing it if I can find a product ready made that fits the bill and just adapt the enclosure to it. Chaining 2 smaller 10" coils of quartz together for instance might work if getting a custom one-off 20" coil proves to be too expensive. The sleeve won't be easy to clean so it needs to be cost effective enough to be replaced along with the bulb ($28) as needed. The more pieces you order, the cheaper they get usually.
These are sample images from vendors on Alibaba. I'm waiting for the UV bulb to arrive to determine the exact inner diameter I need to allow the bulbs to pass through the inside of the coil:


 

Attachments

  • Hbd55561ead33441987c2acea34ce87b6R.jpg
    Hbd55561ead33441987c2acea34ce87b6R.jpg
    96 KB · Views: 3
  • Ha5dca0f388964d878db31310e1cf0699m.jpg
    Ha5dca0f388964d878db31310e1cf0699m.jpg
    110.7 KB · Views: 5

ichthyoid

Vice President
Staff member
Supporting
Messages
3,640
Reaction score
1,852
Location
Cherokee
You could suspend the bulb over a trough or large diameter pvc pipe, for example, and enclose/cover it. That would eliminate the expense of a quartz tube. You would need ports/fittings for in/out of the water.
 

bg2311

Well-Known Member
Supporting
Messages
297
Reaction score
285
Location
Marietta
You could suspend the bulb over a trough or large diameter pvc pipe, for example, and enclose/cover it. That would eliminate the expense of a quartz tube. You would need ports/fittings for in/out of the water.
The bulb needs to be in close proximity to the water to be most effective. I'm not sure what the curve looks like as distance to the bulb increases. Condensation or steam might be an issue in an enclosed space. Not sure how well the bulb would handle getting wet. The glass does get hot. I've seen folks talk about running UV lamps over an enclosed sump. Going to try to keep the bulb/water close to start at least.
 

ichthyoid

Vice President
Staff member
Supporting
Messages
3,640
Reaction score
1,852
Location
Cherokee
Light, like other forms of radiation, follows what is known as the inverse square law-
So,
-at one unit of distance intensity (see below) is X
-at two units of distance irtensity is the square root of X
-at three units it’s the cube root ..& so forth

The intensity of light, formally known as irradiance, is measured in watts per square centimeter, also written as W/cm^2

For a marine aquarium a rule of thumb is to achieve around 90,000 micro watts per square centimeter (written uW/cm^2) in order to denature cryptocaryon irritans, which is the most difficult organism to affect. Lesser dosages can be effective, just to a lesser degree.

There is a lot more science behind all of this, so I’ll stop there. See below for more information, if you like -

 

Dmitri

Well-Known Member
Supporting
Messages
694
Reaction score
636
Location
Dallas
I don’t have MRC sump with built-in UV but I know their larger I-sumps have option to add that in.
I use this UV, it’s 48” tall and diameter of the cylinder is 14”
3 x UV tubes 80 watt each. I change them once a year. Raj recommended every 9 months. I may do 9 month this year.

5B03B644-DC82-446A-94B6-43C17739E273.jpeg
 

bg2311

Well-Known Member
Supporting
Messages
297
Reaction score
285
Location
Marietta
I don’t have MRC sump with built-in UV but I know their larger I-sumps have option to add that in.
I use this UV, it’s 48” tall and diameter of the cylinder is 14”
3 x UV tubes 80 watt each. I change them once a year. Raj recommended every 9 months. I may do 9 month this year.

View attachment 43635
So is there a single quartz sleeve in the center for the water to run through surrounded by 3 more sleeves that house the 3 bulbs? Or does the water fill the entire pipe with the exception of the sleeves for the UB bulbs? I see a central pipe and what looks like maybe one at the bottom left.
 

Dmitri

Well-Known Member
Supporting
Messages
694
Reaction score
636
Location
Dallas
So is there a single quartz sleeve in the center for the water to run through surrounded by 3 more sleeves that house the 3 bulbs? Or does the water fill the entire pipe with the exception of the sleeves for the UB bulbs? I see a central pipe and what looks like maybe one at the bottom left.
It’s a simply acrylic tube-sleeve that protects the uv bulb from water. 3 small tubes. Water comes from the button and exits from top. That keeps the cylinder always full and no bulb are overheating.
 

bg2311

Well-Known Member
Supporting
Messages
297
Reaction score
285
Location
Marietta
It’s a simply acrylic tube-sleeve that protects the uv bulb from water. 3 small tubes. Water comes from the button and exits from top. That keeps the cylinder always full and no bulb are overheating.
Interesting, so those tubes are acrylic and not made of quartz glass? If that's the case I wonder how much of the UVC portion of the spectrum makes it through them. Did you build this UV unit?
 

Dmitri

Well-Known Member
Supporting
Messages
694
Reaction score
636
Location
Dallas
Actually I’m not sure what it’s made out of.
It’s a commercial UV made by MRC
 
Top