UV sterilizers?

newsalt16

Member
I was wondering what you all thought about these? I have heard they are good and bad. I am going to plumb my 75g and so i need to know if i want to do it before i cement all my stuff. If you all think they are good, how many watts do i need for a 75g? thanks for the help.
 

gnorman

Active Member
hmmm, well it really is a personal choice. i set up my first SW tank ( 150 g DT with a 40 G sump ) and i used a UV on it. mine is a FOWLR, with semi aggressive fish. i would recommone one if its going on a such such as mine. they benefits is that it keeps the water more clear, and helps control algaes and parasites. now, it wont keep ur system free of algae and parasites, it will only help control them. the main reason i put one on is to keep the water clear. for a 75 gallon tank id go with around a 14 watt or so.
 

gnorman

Active Member
actually nope, i plumbed it right after the drain. i had a sump with a 2 soc compartment, i used one of the holes for my HOB UV, and the other whole is where the main drain enters into the Filter/micro sock. my powehead pulls from that section, through the UV then the water exits into my Fuge, then that water enters into my 3rd chamber where my skimmer and return pump is
 

gnorman

Active Member
well some people say that if its a reef the UV will kill off beneficial bacteria that the corals like, thus, taking some of the corals feed supply away
 

scsinet

Active Member
A word on flow with these things as it will answer many of the misconceptions that are being posted in this thread...
UV units have to have very slow flow through them. No more than about 5gph/watt. If you pass water through them too quickly, the things you really want to kill, such as ich, will not have sufficient dwell time (time exposed to the lamp) to be affected.
UV units will kill beneficial bacteria going through it, but these bacteria breed far more readily than the bad stuff that is being wiped out, so your system will adjust. Also, remember that most of the beneficial bacteria population lives in the sandbed and on the rocks, not free floating in the water column. Finally, most of the time the flow through the unit is only a fraction of the total system flow, so it's not like it kills all bacteria going through the filter.
Plumbing a UV unit directly onto the return pump or in any other scenario where there are hundreds of GPH passing through it will only serve to drive up your electric bill and give you a false sense of security. You want to set it up with a dedicated loop off your sump driven by a powerhead or something, or with a "T" off your return line and a ball valve for regulating the flow through the unit.
 

sk8shorty01

Active Member
Nice post SCSInet, good way to sum it up. My return pump sends the water back up to my tank, but about 6 inches after the pump I have a "tee off" which has a ball valve directly after it which controls the flow to the UV sterilizer. There is also a ball valve on the return from the UV sterilizer where it "tees" back into the pump return. This setup will allow you to completely shut off the water to isolate the UV sterilizer. I did not actually do the original plumbing (it was done this way when I bought it) but I do think that it is a nice setup as far as work is involved. If I need to do anything with the sterilizer I can shut all water flow down, work on it, then start it back up again. Good luck.
 

dmv

Member
This has been very helpfull I am new to sw and picked up a nice uv but am I understanding that it is good to have if used correctly or not really worth it at all mine is going on a 26 gal bf with 1-2 fish and a small coral thanks guys these posts have been very helpfull,
 
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