Greetings from Melbourne, Australia

[threequote]

aeration I am sorting today, wasn't going to do it until the fish were in but am told it helps cycling as well?

[urbanfarmer]

aeration I am sorting today, wasn't going to do it until the fish were in but am told it helps cycling as well?

It depends. In the right context it might. But, to keep it simple let's just say you can't put too much oxygen in the water whereas you can put too little.

I think you have a great design. I look forward to seeing how it turns out!

[stucco]

@ commander we have those bins in the us. I have four of them.
http://www.decadeproducts.com/products/MACX/main.html

[foodchain]

The UV sterilizer won't kill the bacteria in the filter, it will however kill the pea green soup algae that plagues ponds, and if you push the stocking densities and ever have a problem with ich or anchor worm or some other parasite it will assist in eliminating them while suspended in the water column and off the host.
I have used UV sterilizer's for years with no adverse effects on any bacteria or filters, both indoors and out, and on both fresh and marine systems. The only thing I dislike is having to change the bulbs and having to be mindfull of NEVER touching the bulb with your bare hand as the oils on your hands can cause 'hot spots' on the bulb itself. Never, never run it without water. As the water cools the bulb. NEVER look at it when on, if the UV kills nasties in the water, what do you think it does to your eye?

[foodchain]

If you were to add a gas exchanger down stream from the UV this would help with some of the aeration as well. Or/and depending on how much you need...run a piece of tubing with slots in it across the return line. So the 'clean' water coming back to fish tank sprays out due to pressure and aeriates on the way down to the water. Not recomended to be used by itself here. But the more contact water has with air the better off your going to be. I have seen this in use with drilled holes instead of slots. Many variations out there. This keeps from having to have another machine, Good luck.

[foodchain]

Probably not needed, but a particulate filter in front of the UV will increase the effecientcy of the UV filter as the particles protecting the stuff you want to fry harbors them, and protects them from the cleansing light. Just a thought. Pay attention to flow rates, you can't have the water exposed to the light too long.....but it's possible to expose for too short of time, thereby reducing it's effectiveness. Just keep the flow high enough to cool the bulb. Your manufacturer should have sent you a optimal flow rating in the paperwork.
There are DIY ones out there, please pay attention to your flow. Bulbs get expensive.

[keith_r]

i wouldn't bother with uv... at least with an ap system.. when there is a bloom, the uv only penetrates a very little bit, so doesn't help a whole lot..
most ap'ers get the initial algae bloom after their system has been running.. covering the ft and adding aeration will get you through this stage, and when the algae dies off (after a few days of being covered) it produces a chemical that inhibits further algae blooms..
oh.. and adding aeration to your ft will help with cycling..the bacteria do consume oxygen

[Oliver]

The UV light adds no value to your system. Take the electricity it uses and apply it to added aeration.

Not all bacteria live in the bio-filter.

Heterotrophic bacteria remain suspended in the water and are necessary to mineralize the solid fish waste and other organic material.

Autotrophic bacteria also are found in the water and some of them attach themselves to the media of the bio-filter where they nitrify the ammonia in the system along with those found in the water.

If the UV light is effective in doing its job, it will kill all of the heterotrophic bacteria and much of the system's autotrophic bacteria.

If you have been using a UV light and it has not appeared to adversely affect your system, then consider yourself lucky, as it is not doing a very good job. You might as well turn it off and save the electricity and the cost of replacing the bulb.

Oliver

[foodchain]

Your above statement is in contradiction. The UV has no way of getting to the bacteria in the filter. Set one up and try it. They are very good at what they do. I won't run an intensive culture without one.
The amount the light penetrates depends on the wattage you have, take one apart and look at the gap between the bulb and the sleeve. It's not very big as it's meant to do a thorough job, and this is best acheived by limiting the amound of water that goes by...therby prolonging the exposure time. If you are only running a handfull of fish, you are absolutely right, there's no need. But in an intensive culture you really do need this. In any livestock you run, the higher the concentration the higher the risk of an epidemic, in aquaculture, which is what this is when you remove the grow beds...you may want to at least consider it. Especially if you are going to push the production limits. Again...low populations make it a waste of money. High populations is an investment you can't live without, or if you do...it's at your risk.
Yes, the UV will kill the bacteria in the water. And? It's supposed to. That's the purpose of this unit.
Technically the bacteria are on everything in the tank, including the fish.
Your not worried about the bacteria in the water so much as it is the bacteria in your GB, it's there that the waste is broken down. That's why there's a corelation between the amount of fish and the amount of GB. Too little and there's not enough surface area right? Your bacteria don't migrate through the water from the fish to the GB's. They are dividing, and multiplying. Not one organism traveling around. AFTER the system is ballanced, a UV light will do nothing to the filter, prior to balancing it MAY prolong the process. IF the sterilizer wiped out the bacteria in the filters reefers all across the country, public aquariums, aquaculture facilities, etc would all be having serious levels of mortality.
Go to your local public aquarium, request a behind the scenes tour. You will either see a UV sterilizer or Ozone. They both do similar things, sterilize the water.

[Oliver]

foodchain:

I stand by my previous statement. Please re-read it and see that what I said is different than what you are referring to.

This is not an aquaculture system to which we've added some grow beds/bio-filters. It is an aquaponics system that has different and special requirements. It is about the balance between the fish, the bacteria (all the beneficial ones that live throughout the system) and the plants.

I believe you have over simplified the beneficial bacteria by grouping them into one type that are located in one place, the bio-filter. The truth is that there are at least two types of bacteria that break down fish waste, of which only one (autotrophic) reside on, but are not limited to, the substrate generally found in the bio-filter. They don't always remain there or there wouldn't be any in the water, which there is. The heterotrophic bacteria, as I have stated, remain in the water until they attach themselves to organic mater (which are also suspended in the water) for their feeding duration and are susceptible to the destructive effects of UV light as are the autotrophic bacteria that also freely float around in the water. The heterotrophic mineralize the solid fish waste, and other organic material found everywhere in the water. But, I am repeating myself here.

I will say this only one more time, turn off the UV light and allow nature to do what it does best, converting all fish waste into useable nutrients for the plants. Stop trying to over control what is happening in the aquaponics system. Filter your water going into the system, grow plants from seeds and don't transplant them from soil and breed and brood your own fish to help keep your system pathogen free. Add lots of aeration to the system to keep it healthy. Low dissolved oxygen content is a huge detriment to the health of the system and is often thought to be some other problem.

Oliver