Nitrate Reactor

[gatekeeperdi]

Hi there,
I have a deltec NFP509 nitrate reactor that I've been using for some years now. Over this time I have tried feeding either the deltec fluid or vodka and currently I'm using deniballs and denimar powder to feed it.
No matter what I have used as the food source, after a few weeks or a couple of months the inside of the reactor becomes heavily clogged up with the bacteria and/or the two pipes at the top get clogged up needing it to be cleaned out. The water and bacteria inside the reactor is drained through some clean tights and returned to the reactor then.
If I reduce the amount of carbon source feeding the nitrate levels on the tank then climb. The water supplied to the reactor from thetank is controlled using the ORP probe via my GHL Profilux computer and doser.
Has anyone any advice of the best carbon source to use and how to reduce the clogging of the reactor please?

Thanks, Di

 

[gatekeeperdi]

In case anyone is interested I had this reply from Tony at D-D.

"The bacteria collecting inside the reactor illustrates that the carbon source is working well. I dont think a change in the carbon source is the answer.

As you know the reactor is designed as a low oxygen environment/home for denitrifying bacterias. Given a carbon source and Nitrate the bacteria's colony forming numbers will increase and this will result in a bacterial mulm that has converted available Nitrate.

So in that we must look at the following.

1. Is the reactor appropriately sized for the aquarium or load.
2. Are you over feeding as the more Nitrate load you put on the system the higher the growth rate of the bacteria
3. Do you scrape off the old bacterias when the unit becomes clogged thus exporting the bacterial mass? If left in the reactor in a semi clogged state the flow will drop and the bacteria start to crash and release nutrient back into the system and the cycle begin again.

Basically the reactor is doing its job, you must keep in mind that if the Nitrate levels in the tank is very high due to over stocking or feeding the unit will clog quite quickly , its akin to feeding a chiwawa the daily food ration of a bulldog. The Chiwawa will keep on eating but the results wont be pretty.
The answer would be to look at the food ration going into the tank and the stocking and if the reactor is in fact a good match for the system and cleaning it more by decanting the water from the reactor, scraping off the inner element to remove most of the bacterial mass and then installing into the reactor and topping up with the original water again.
Obviously dont wash the elements in fresh water as you will crash the reactor when you start to run it again. If the element if very dirty scrape and wash in tank water before using the original water to go back into the reactor. Then run it for a few days with the effluent addition turned off but carbon source on to kick start it again.

I always found 50/50 Vodka and RO water the best carbon source for my NFP509 dosed at 8ml a day (4 x 2ml on a timer through the day)



Best regards
__________________
Tony"

I have the NFP509 nitrate reactor and the tank water volume is about 900 litres. I have only recently set this tank up, upgrading from the RSM 250 & have 6 fish & a mixture of corals in there at the minute. The nitrate is 10, some of which I think has leached out of the live rock that was transfered.

I had been led to believe in the past that the bacteria mulm in the reactor was what broke down the nitrate from the tank & had been trying to preserve some of this when I cleaned out the reactor if it had become blocked. It will be interesting to see how the tank nitrate levels go if I am harvesting this instead of presrving it!

I'd be interested to know what people think about it (apart from me apparently having my understanding completely wrong, lol!).