Yet another angle to a cycling problem if you will.

[HoundsNTrout]

OK, another little question not exactly like the others I've learned along this 3 year path of raising trout in a Recycled water system.

I have 3 totes ( IBC 275G ) I have 20 Gallon plastic totes as my bio filters and a 'sock filter' changed and rinsed daily. Bio capable and set up to take care of 8ppm ammonia in 8 to 12 hours. Has to be since I keep 1500 to 2000 Four to 5 inch fish in each one then release.
Flow rate is 300GPH through the bio filter and also tons of water movement with four stones set on high.

Anyway, LOOK a chicken. lol

So question. Cycling a tank at 50 to 52 degrees takes a long time, and the Nitrite part of it actually seems to always cycle first. I do a few weeks at 50, a few at 52 to 54 and then a week at 60 degrees since I want my fish to mostly be in the 55 to 60 degrees for faster growth and eating frenzy's.
Tank cycled nicely in maybe 45 days I think it was, but for some reason I decided to take a ph and I was like WHOA ! Apparently in time it dropped from 8.2 ( which is awesome btw for trout ) to below 6.

So I did a huge water change with nice fresh 50degree well water to get it all back to 8-ish. I then discovered the nitrite cycle was not working. Its like I started all over again, right back skyrocket like I was just beginning. The ammonia cycle stayed the same nice 8ppm down to zero in 8 to 12 hours.

Should I have added fresh water more slowly? Almost seems like the nitrite part of this was in the WATER rather than the media. I also have (6) One gallon jugs filled with stones on the bottom to help with the tremendous amount of ammonia that COULD build up with this many fish.

I also change water every other day 50 gallons of fresh. I have a chiller if needed and everything goes fairly well.

So, I'm gonna wait and see what happens but I hope I didn't kill off the nitrite eating bacteria. Water temps exactly the same, just fresh.
Could it have liked the lower ph? and now back to the 8.2 ph it doesn't like that?

Very weird.

It is very possible to keep trout in a closed and recycled system as long as you have a big ass bio and capable of at least 8ppm in 8 to 12 hours and change some water daily or every other day and clean daily the bottom and your sock filter.

Thanks, sorry for the crazy long post.

 

[HoundsNTrout]

So did I kill the nitrite eating bacteria? I don't get it, just by changing the water?
Everything was rock and rolling until I changed the water. ( because the ph was way too low for trout ).

 

[squint]

Nitrite oxidizing bacteria (NOB) are inhibited by ammonia and both types of bacteria are inhibited by low pH. My suggestion is to measure pH regularly and add alkalinity which is consumed during the nitrification process. Nitrification rates peak at a pH of around 8.3.

If you want to test the bio filter, a sustained ammonia test might be more realistic than an 8 ppm spike and less inhibitory of nitrite oxidizing bacteria. I think smaller, more frequent doses of ammonia are in order.

Lastly, I like to treat the bacteria like fish and not subject them to rapid changes in temperature, pH, TDS, etc., so I would also recommend slowing down water changes.

 

[HoundsNTrout]

I'll give it a go. Thanks.
Everything cycled a day after posting this. LOL
However, I'll try getting it to 2 ppm every 6 hours then right before I go to bed maybe 3ppm.

Obviously small fish are not going to produce 8ppm over night so the next question would be is there such thing as too much bacteria? And if I get the tank capable of 2-3ppm ( which is definitely is right now ) will the bacteria grow to meet the demands? I would assume so .

When I started this project I did the add ammonia daily method to keep adding and adding until everything cycled, changed the water then re-tested and never had a problem. It was probably in the range of 12 to 18ppm at one point while cycling. It took FOREVER.
This time around I decided to keep it around 4 until everything went down to almost a half or 1ppm then added tiny bit more than the first time and so on.
So its not like I suddenly shot 8ppm ammonia in a tank that was only used to 2 or something.

But, anyway it takes 8ppm over night or maybe 10 to 12 hours right now. So I'll start adding smaller amounts 3X per day and see how that works. Obvously cycling the smaller amounts much quicker.

Thanks . This cycling is sort of new to me since I was on a relatively open circuit before this with ample water supply and pumping in water just as fast as it went out. No issues, but I want that well for something else now. lol

And yes, that is a giant NYS Brookie I took in the Adirondacks 4.5 pounds in early May.