I finally got around to purchasing a UV sterilizer despite the fact that the cooler weather has been effective in fighting algae. I had the opportunity recently to purchase a 120 watt UV sterilizer at near half price of $700, but figured I could buy alot of algaefix for that amount. I was surfing ebay the other day and found a Chinese brand UV sterilizer with 55watts for $79 + 20 shipping. So I modified my plan and added it to my box filter line which has about a 2000 gallon per hour flow. Not all my pond water will flow through it but the volume is close to full pond turnover per hour. 55watts at 2000 gph gives me 36 watts per gallon which should suffice for algae killing. I may not use the UV during the winter, but I have turned it on for now and hope to see a change in clarity since algae keeps sneaking back in due to the amount of warmth and sunshine here in the southern USA.
I installed two 2×1.5 Ts on the main line to the filter box. from the 1.5 side I added a single union ball valve which connects via female threaded adapter to the UV. I have a valve going in and coming out in-case I need to remove the UV for maintenance I can shut off the flow through the Tees. Between the Tees I added another ball valve so I can control flow through the main pipe and force some of the water through the UV.
The UV is only 1.5 inch piping so I could not direct all the flow through it without reducing overall flow to my filter.
UV Sterilizer – $99
plumbing parts – $35 – the union ball valves were about $9 each.
time- 2 hours disassembling reassembling
This is not a strong sturdy piece of equipment. The plastic housing is rather thin and I will need to be careful not to step on it. I thought about mounting it on a board for additional stability but the ground is level where it sits. It should work like other UVs though, and for 1/5th the price of other 55Watt UVs I can replace it if it breaks. Bulbs are readily available when I need to replace it. I would recommend it to anyone on a tight budget. Standard US female threaded PVC adapters seem to fit this unit if you don’t want to use the barbed fittings that come with it.
This is a bit of a challenge. Mine did not want to open. IF you press in the button on the side then twist counter clockwise about 1/12th rotation, it should come apart. There is a catch that locks it horizontally. Then you have to remove the threaded cylinder that holds the outer glass tube. Once the glass tube is removed the bulb merely unplugs. Be gentle so you don’t break the glass tube but forceful enough to remove it.
After 12 hours of running I can see the bottom again. Still not perfectly clear but better than yesterday.
After 3 days the water is very clear but still has a green tinge.
After 1 week of running no more green colored water at all. It was so easy to clean the mats in my bio filter. No real dead algae debris either.
4 Months later, The unit has worked well but the uv bulb has burned out, possibly due to ice or condensation on extremely cold day. Replacement bulb $28.
AFTER 3 Years of service the housing developed a leak at one of the seams where another piece of plastic is welded on. the weld was a thin are in the housing so I assume the water pressure overtime broke through the slit. The quarter inch slit was losing 200 gallons per day. Time to buy another.