Best UV sterilizer?

I think that my 50 and 65 gallon planted aquariums have high bacterial loads for some reason. Previous antibiotics treated never seemed to do much. Both tanks have zero ammonia or nitrite but some nitrate and phosphorus. I do 50% weekly water changes. I have well water that is super soft. The tanks are moderately stocked. The 50 gallon is 25 years old! But, every time I add new fish to it, they don't survive. It's full of a colony of rosy barbs that are self sustaining since 2002 (19 years!) but no other fish now. It has been this way for a I put in two baby bristlenoses last week; they did great for two days and then just died. And no, I never saw the barbs interact with them. The tank is FULL of algae and java moss. I had a Queen Arabesque pleco in there for 14 years but most of that time, she looked to have fins that were rotted off. She died earlier this year.

I reset up my 65 gallon this year, and even with quarantine, there's been a high mortality in there (even without the one ick outbreak from the first new fish with the UV sterilizer going). My cardinal tetras are missing fins although there's no sign that anybody did it to them. I can't keep Sterba's cories alive (down to 2 from 11 total this year). My new discus seems ok but is getting a little white on the fin tips. So, I'm thinking high bacterial load. I treated for BGA algae with erythromycin a month ago (before the discus). I started the 65 gallon with a UV sterilizer earlier this year, one that is in the water. It worked great until I noticed the lamp chamber was flooded. For many years, I had a huge pleco in there (don't worry, that was before discus), and I had similar UV's where the lamp chamber always flooded which is dangerous (shock hazard). I had a great HoT UV filter until I discovered it was leaking out the bottom. Unfortunately, I didn't discover this until the stand was soaking wet with mold. I have a Turbo Twist UV in my turtle tank but, since half the tank is air, I hang it inside, and it drips constantly. So, an external UV won't work either.

What brand and type of UV sterilizer do you use? I've yet to find a good one! Thanks.

Hi Brutus, It sounds to me that you are not changing water often enough. Adding fresh water will help the fish and remove some of that bacterial load.
Pat

Ok being there not discus tanks and more community tanks I think your not doing your nitrate test correct. You have to shake the heck out of the second bottle and the vial when mixed. It sounds like old tank syndrome. Your barbs have adapted to the water but anything new will die because it’s just to hard to acclimate too. I have a 90g community tank that is planted and only gets one 50% water change a week and is fine.
For a uv steralizer I use the green killing machine. Replace the bulbs every 8-12 months.

Thank you for the replies. I am fully aware that doing more water changes would certainly help. I am gone from home 45 hours a week, and I spend 35 hours on my animals, aquariums, and ponds already, mostly on the weekends so it would be difficult logistically.

As for the nitrate tests, the ones that hobbyists buy are no good. I'm an analytical chemist, and I run my water on the ion chromatograph that I have at work so I can have accurate results for fluoride, chloride, nitrite, sulfate, and nitrate for which I calibrate. I also run ammonia on a discrete analyzer. I plan to retest my well water and tank waters (I also have a 20 gallon planted tank with a self-sustaining colony of panda cories, and new fish added there also don't last long either) on Monday for anions and ammonia.

With regards to the Green Killing Machine, yes, I had those when I had my pleco who lived 26 years. Without a UV, sometimes the tank would bloom with bacteria or suspended algae. The Green Killing Machine worked well for a while. The problem with it is at least the one I had was sealed so you could not buy a new UV bulb. You had to buy an entirely new unit. Other problems that I had with it included that it was a lot of parts that would get stuck or pop off, there's no way to tell if the bulb is on or working, it clogged often (but that was with the messy 15" pleco), and it kept falling off the glass. I had to stop using it last year when I noticed a heavy metallic smell coming from it. Since I couldn't get to the bulb which they sealed in, I presumed that the bulb had broken and exposed the electronics to the water. Anyway, I found it to be poorly designed. Is yours like that?

So which of these would be better? I've had them all before. The first worked great for a few years and then leaked out the seal on the bottom of the HoT filter and destroyed my old stand. The second one, you cannot get to the bulb, you cannot clean the flow path, and you cannot tell if the bulb is even working. I've gone through about three of those in the past. The last one smelled like metal and must have ruptured inside (I tried to cut it open to see but couldn't; they are made like Fort Knox). The third UV is a type from various manufacturers that I've probably had six of those! In all cases, water would get in to the lamp zone and flood the parts that are supposed to stay dry, and then I had to stop using it. This is the last kind I bought in January. It flooded by February, potentially electrocuting the fish (nobody died though). I've wasted so much money on UV sterilizers! That's why I thought you guys would know of a good one!

Don't they make anything like this that's built to last? [And doesn't leak. And where you can change the bulb and see the bulb?]

My guess is no. So, if I get another, I'm risking the lives of the aquarium animals as much if not more than I might be helping them! Is it worth the risk of leaks and electrocution to lower the bacterial load that's giving my fish minor but constant fin rot?

https://www.chewy.com/aquatop-hang-o...m-uv/dp/168631

https://www.chewy.com/aa-aquarium-gr...hine/dp/158403

https://www.amazon.com/Sterilizer-Ad...9806462&sr=8-6

The bulb comes in a sealed plastic container it’s $24 I replace every 8-12months. Never had a problem. I’m running 3 of them now.

Look at Pentair sterilisers. All the serious reefers use them . I’ve got one and love it! Not cheap though

If spending a little more dollars on a unit that will last you a long time and easy to install and do the maintenance work required, go with this unit: https://www.bulkreefsupply.com/25-wa...traviolet.html
I purchased this unit for my 125-discus tank, once over the sticker price, I'm glad I got this UV for my tank.

Test for DOC.

I have a bulky 9W placed in the return chamber in a sump. No connection to pipes just hanging there as internal filter.

I didn’t know how effective was it till I accidentally switched it off for a week. Water become browny, much more algae, dust on substance. I was wrapping my head around that - what’s going wrong in a tank till I realised that it it was off.

It costs only 50$ but effects are amazing

https://www.amazon.com/Aquariums-Sterilizer-Submersible-Machine-Replace/dp/B07DFR6CRQ/ref=mp_s_a_1_10?dchild=1&keywords=ZSSSS123+uv+filt er+9w&qid=1620145725&sr=8-10

Thanks. The UV that Pablos listed is just like the last one I had. The lamp chamber flooded after less than two months (I had never even opened it). The gasket is just not efficient enough. I ordered the 125 gallon size of the Green Killing Machine, coming tomorrow. I used that one for maybe a year with my pleco but it kept clogging with black ramshorn snails. The 65 gallon had hundreds of them (I put in ONE a decade ago because I was too lazy to take it out to my pond). When Plecy died, I moved some of the snails to my pond, and I bleach murdered the rest. The newly-set up 65 gallon does have Malysian trumpet snails and a tiny species of ramshorn that I moved from my other planted tanks. They are good snails and not many in number but could still clog the filter Since the Green Killing Machine UV chamber is sealed, I cannot clean it out. It is a poor design. There is a pre-filter so I'm not sure how my old one became jammed with snails, and then it smelled like metal, and I think something ruptured so I stopped using it in 2019 I think.

maybe you where not lucky with that particular unit. Mine is working for quite some time already (6-7months) without an issue.

I'm going along with Pat, more water changes needed, but with the drought in California I might have use the UV.

Cliff