My thoughts FWIW.....keep it simple and cheap, don't over engineer to fix what's probably inconsequential issues.
Buy the cheapest and highest wattage unit you can find - they all use the same replacement bulbs which will be an ongoing expense. IF the wattage is higher than recommended for your water capacity, it will still be effective as the output diminishes over time, reducing the frequency of replacement.
Plumb it directly in the return line to the tank. No need to buy a second pump or add additional plumbing.
Run UV full time, why wait until a problem occurs?
Run at whatever flow rate you desire for the return to tank, don't worry about altering the speed to accommodate the UV.
I have read the various opinions/recommendations about flow. Some say it depends on what problem you are trying to solve. For example, the reproduction rate of certain bacteria that causes cloudiness in the water column is to double every 20 minutes or less. In that case, the higher flow rate will more than keep up with the bacteria population explosion and aid in water clarity.
Some feel that a slower rate will be more effective in fighting parasites. Likewise, algae in the water column can be tackled by UV, and since it reproduces more slowly, why use a fast flow rate.
In either case, the UV alters the DNA of single cell life to prevent reproduction.
I view it a bit like exposure to the sun's UV rays. If every 5 minutes of sun I get is followed by 5 minutes of shade, I'm still gonna get sunburned if I'm exposed too long. Likewise for the bacteria. If I have a flow rate of say 5 to 10 times tank volume per hour, then the parasites I'm trying to target are still getting exposed to 6 to 12 minutes of UV every hour while the bacteria with the rapid reproduction rate are still getting exposure before they are able to double in population in 20 minutes.
I can turn off the power to the sterilizer if I get concerned that I'm using too much UV (to extend bulb life perhaps), but so far that's not a problem. I can also plug it into a receptacle/switch shared with the return pump to make sure it is turned off anytime no water flow.
A lot of room for different opinions based on individual experience. In any case, I recommend the use of a UV sterilizer and look for the cheapest you can buy. Again, they are really very simple and most of the products on the market, high or low priced, use the same replacement bulbs.
Buy the cheapest and highest wattage unit you can find - they all use the same replacement bulbs which will be an ongoing expense. IF the wattage is higher than recommended for your water capacity, it will still be effective as the output diminishes over time, reducing the frequency of replacement.
Plumb it directly in the return line to the tank. No need to buy a second pump or add additional plumbing.
Run UV full time, why wait until a problem occurs?
Run at whatever flow rate you desire for the return to tank, don't worry about altering the speed to accommodate the UV.
I have read the various opinions/recommendations about flow. Some say it depends on what problem you are trying to solve. For example, the reproduction rate of certain bacteria that causes cloudiness in the water column is to double every 20 minutes or less. In that case, the higher flow rate will more than keep up with the bacteria population explosion and aid in water clarity.
Some feel that a slower rate will be more effective in fighting parasites. Likewise, algae in the water column can be tackled by UV, and since it reproduces more slowly, why use a fast flow rate.
In either case, the UV alters the DNA of single cell life to prevent reproduction.
I view it a bit like exposure to the sun's UV rays. If every 5 minutes of sun I get is followed by 5 minutes of shade, I'm still gonna get sunburned if I'm exposed too long. Likewise for the bacteria. If I have a flow rate of say 5 to 10 times tank volume per hour, then the parasites I'm trying to target are still getting exposed to 6 to 12 minutes of UV every hour while the bacteria with the rapid reproduction rate are still getting exposure before they are able to double in population in 20 minutes.
I can turn off the power to the sterilizer if I get concerned that I'm using too much UV (to extend bulb life perhaps), but so far that's not a problem. I can also plug it into a receptacle/switch shared with the return pump to make sure it is turned off anytime no water flow.
A lot of room for different opinions based on individual experience. In any case, I recommend the use of a UV sterilizer and look for the cheapest you can buy. Again, they are really very simple and most of the products on the market, high or low priced, use the same replacement bulbs.
