I've had several PM's recently asking about UV. Sizing, types, brands etc.

First a couple of threads on uv which hopefully clear up some misconceptions, and offer a different point of view:

My observations - white spot, UV, skimmer

uv zapper or not????

U.V.

UV, why and what for?

Sizing:

Basically the bigger the better. You can't OD UV.

I would recommend starting with a 40watt as they tend to be "modular", so that if you upgrade to a larger tank, you can tidily gang up a second one to give 80watt etc.

Also, UV tubes efficiency diminishes rapidly initially then plateaus over time. If you "oversize" the unit, and run lower flow rates through it, you can save significantly on bulb replacement costs.

Running a 40 watt factoring in a 6 month bulb replacement cycle (longer if you "oversize") costs around $20 a month

Important Features to look for:

High Output GPH t5 / t6 style pure quartz bulbs. (It DOES make a difference)

Recommended Brands:

(Unlikely to find suitable brands "off the shelf" in shops here unfortunately)

Aqua UV

Emperor Aquatics

Deltec

Layton

thanks for posting that Layton, i was going to get around to sending you a pm with some questions, now i dont need too.

cheers

I've had another PM basically asking what the difference between different brands are. I'll try and explain what makes a quality UV unit here.

What's the difference between a good UV unit and a crap one?

Basically the difference between the units is the quality of plastic, and seals, and the type of bulbs used.

UV can be hard on plastic, it breaks it down much like it breaks down organics in the water (splitting those C=C bonds mainly). Viton seals hold out better under UV exposure. UV will tend to turn plastics brittle over time. Quality plastic will prolong this.

Bulbs are probably the single most important part, to be really effective you need a unit which uses GPH t5 / t6 tubes, with pure quartz envelopes. Standard glass will block the majority of the useful UV spectrum. Glass bulbs are common in smaller, cheaper brands. Some UV units are really made for "clarifying" which is more of less useless for what we want it to do. It'll "clarify" a pond of algae, but won't do a lot more than that.

The brands I recommended above, I know use the right type of bulb. There may be more, but they are the ones i've personally looked into.

Virtually every UV unit uses pure quartz sleeves.

Also, don't bother spending extra money on models with a sleeve "wiper", they are a waste of time.

Where do I get one?

Aqua UV - stocked by Marine Depot (make sure you order the 240 volt version)

Emperor Aquatics - can probably be found online too, but Marine Depot don't appear to carry them.

Deltec - shops that are meant to stock deltec gear, or ask reef.

Layton

Any thoughts on Helix-max uv????

There are larger "pond" UV systems available locally (not exactly cheap either $$$ ). If they have a quartz sleeve and relatively high wattage (40+), would that be alright? I think I read/heard somewhere that there is also a difference in the space between the bulb and water (or something like that) between pond and marine UV's. Does this ring any bells or is this not a factor?

Any thoughts on Helix-max uv????

I think you've asked before.

They use a PL-L style bulb which is nowhere near as good as the GPH t5 /t6's

They try and compensate for that by using the helix to try and maximize exposure time.

Personally i'd avoid those helix style ones. Much harder to clean. And often they are just trying to compensate for poor bulb performance.

Also note that the Deltec UV's are re-branded RuWal units. So RuWal can be added to the list of "known good" UV units.

Layton

There are larger "pond" UV systems available locally (not exactly cheap either $$$ ). If they have a quartz sleeve and relatively high wattage (40+), would that be alright? I think I read/heard somewhere that there is also a difference in the space between the bulb and water (or something like that) between pond and marine UV's. Does this ring any bells or is this not a factor?

The distance from the bulb to the water is important, but that is generally determined by the type of bulb.

Also the outer diameter is important, but not necessarily a purchasing decision. You can adjust for larger diameters by reducing flow, and vice versa.

Layton

this from Bob fenner, obviously doesn't have Laytons limitless knowledge, but worth a read..

Ultraviolet (U.V.) radiation is sometimes employed in water purification systems for tropical freshwater, marine, cool water and pond systems. U.V. sterilization can be very effective in reducing free-floating algae, bacteria and other microscopic planktonic organisms. A U-V sterilizer should be of limited value in a properly set-up and operated marine system. Too many people are of the opinion that zapping their water with a ultraviolet device confers some "holy grail" water quality improvement. This is not the case. An adequately sized U-V for the volume of water in a system and rate of post-filtered flow will improve water quality nominally in terms of lowering overall free-floating microbe levels. Additionally there is a slight improvement in dissolved oxygen, oxidation of metabolites, ozone production and skimmer efficiency. It is up to the individual aquarist to decide whether this incremental improvement is worth the cost in procurement, electrical consumption, bulb replacement and maintenance.

In other words save your dosh for a bigger skimmer

this from Bob fenner, obviously doesn't have Laytons limitless knowledge, but worth a read..

I wonder what he bases that opinion on ;-) By the sound of it, it's based on experience of some crappy "hobby" grade UV "clarifier" he used 30 years ago.

Why do you think I'm so specific on what to look for, and what to avoid in a UV unit.

The crap ones are worthless, and the good ones are indispensable as far as i'm concerned.

Half the problem with this hobby is that there is so much misinformation and misconceptions around.

That's why i'm so persistent with my posts on this forum Hopefully they offer a different point of view, and make people think a little deeper on why they choose the methods they do to run their tank.

Layton

Hopefully they offer a different point of view, and make people think a little deeper on why they choose the methods they do to run their tank.

The exact reason i posted this.

true, but to be fair that info of fenners is rather old (or at least his reference information is) still, i dont think UV will work for everyone - again, as often as this is brought up, it is true - what works on one persons tank wont necessarily work on anothers.

Those sneaky organics, I didn't realize they are so fast they can dodge photons (presumably with matrix style contortions). The ones in my tank must be retarded :lol:

why are the TUV PL-S bulbs no where near as good as the GPH t5 bulbs?

The Pondmaster units use Philips bulbs (like the Aqua Medics) and you can link multipule units together with ease as the outlets are at opposite sides of the unit.

Running cost of a UV is really a bargin if it works out at $20 at month.

why are the TUV PL-S bulbs no where near as good as the GPH t5 bulbs?

They output less UV per watt, and also the physical configuration of them means that they aren't nearly as efficient at getting the UV to the water as the GPH t5 / t6... it can make a significant difference in the end.

The Pondmaster units use Philips bulbs (like the Aqua Medics) and you can link multipule units together with ease as the outlets are at opposite sides of the unit.

Running cost of a UV is really a bargin if it works out at $20 at month.

Power on a 40watt is under $4 a month. Spreading the cost of bulb replacement every six months brings the total to around $20 a month max.

Layton, do any of the units you have mentioned have bulbs which are available in NZ or do they all need to be purchased from overseas

Don't know. I guess somewhere like "Lamp Specialists" may be able to supply these GPH bulbs.

But part of the reason why I got the Deltec one, is that reef fully supports the Deltec products he sells (in addition to being very competitively priced). When I need a new bulb, I'll get hold of him.

That way I don't have to deal with bringing them in replacement bulbs from overseas myself, worrying about breakage / returns / insurance etc.

You say indespensible as far as you are concerned. If they are as good as you are trying to make out, why isn't everyone using them to control nutrients. Only 2 of the last 9 TOTM on reef central use them. Don't know if any of the top tanks in NZ use them....Reef, Pies, cracker, westy ??

How about some before and after photos of you tank, showing the improvements, before everyone rushes out buying Deltec UVs on your scant evidence.

3 of that 4 dont use them, Dont be so modest PP your tank should be on that list

You don't believe me, that's fine. I'm not here to prove different methodologies to people, or force people to run a tank the way I would choose to run mine.

Why don't more people use them? I think you hit the nail on the head with the quote from Fenner. Misinformation, misconceptions, and just plain ignorance on what UV actually does. The majority of people still have the perception that because UV kill bacteria in the water it's bad for the tank.

The evidence supporting UV is there, just look for it.

I'm not into posting photos for this purpose. Photos prove very little.

You never post photos Layton, got to wonder why.

Ignorance from people far more experienced and successful than you, come off it layton, just like your zeovit and refugium arguments. And to compare yourself to the likes of Fenner, please. I note Borneman, who you often quote never mentions this ability of UV to reduce nitrates and phosphates in any of his material, nor anyone else that i can find, except some obsure reference you dug up from the internet.

It's not that i don't believe it has worked in your tank, but to try and believe that the majority of marine aquarists don't use it because of misinformation and ignorance, come off it.

It is one thing promoting alternatives or new ideas, but to state them in the way you do as fact is wrong.

Only 2 of the last 9 TOTM on reef central use them.

I count 4 out of 11 TOTM this year run UV 36% of TOTM use UV, which I would consider a much higher percentage using UV than the general population of tanks. And it tends to be some of the better ones too ;-)

http://www.reefkeeping.com/issues/2006- ... /index.php

http://www.reefkeeping.com/issues/2006- ... /index.php

http://www.reefkeeping.com/issues/2005- ... /index.php

http://www.oregonreef.com

But that's beside the point, these pics don't prove that UV works, the research does.

Just out of interest. Don't you believe the claims i've made because in your opinion "top tanks" don't use it? Or is there some other, more valid reason why you don't believe them?

Layton

so youre happy to post pics of stunning overseas tanks but not youre own?????????????????