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Fish slowly dying, plants not growing

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To begin thanks in advance for any and all help. First let me explain the issue and than I will give some background information. My 7 plants, Basic tomato, an established big boy tomato up rooted from soil outside, green pepper and 4 strawberries, are all dying except for a very small amount of new growth. All the plants, except the big boy, were all bought at Walmart about a month ago. The Pepper plant had a small pepper on it. it has not grown at all. most the leaves on all plants are wilting. Not showing any other signs of issues. i.e. yellow or black leaves, color change, or spots.

Ok so a little background. About 10 months ago I started a system. I started with about 2 dozen gold fish in my 40 gal tank. It is a basic flood and flow system using fish gravel as the medium. I tried several other systems before this but for different reasons none of them worked for my situation. Anyways most of the goldfish died pretty quick. only about 6 survived and grew pretty quick. I tried several different plants. Egg plants, tomatoes, strawberries, peppers, lettuce. Some from seeds and other from store bought plants. It was weird, none of them grew. they just stayed the same for months. one by one, weeks apart, a plant would just die immediately with no warning. Suddenly and with in hours would go from a full plant to literally nothing. The other plants would be fine for awhile. Eventually the last plant died. None of the plants ever produced fruit or grew. I eventually added a small frog and a sucker fish to help the cloudyness of the tank. That part worked well. After all the plants died I stopped flowing the water and let the tank be. The water got very cloudy. About a month ago I dumped the fish pebbles out and got expanded clay pebbles. I also bought 20 fish. 12 of them were small gold fish and the other 8 were a tetra. All of the tetras died pretty quick and about half the new goldfish including yesterday my biggest goldfish from the previous batch 10 months ago. He was about 8 inches long, kinda sad.

Because of goldy dying I am jumping into action. Since starting the system I have done a lot of research but am constantly getting mixed messages and having a hard time getting my system working.

With the first system I had the flood and flow on a 30 min on 1 hr off interval. I have read a lot of disagreeing info on how long to have it on/off. I currently have it set to 30 min on and a hr and a half off.

The lights I am using are led bulbs. 6 of them are small about 20 watts and I have one large one about 60 watts if I remember correctly. They are currently on a timer for 12 hours on/off. I have tried adjusting the height several times with no noticeable changes to the plants.

I am stumped. The fish don't seem to have any visible issues and they are definitely not sluggish. I do feed them a lot, three or four times a day, but the cycle seems to be working well. The plants just don't seem to be growing or absorbing the nitrate. A lot of forums suggest to add more plants but if the ones I have are wilting and not growing I don't see how adding more plants could possibly make things better.

ammonia seems to be about 0.25
Nitrate at least 200
Nitrite about .5
Hardness very hard
moderate alkalinity
ph about 6.8

Any help would be much appreciated!!!!!!!!!!!!!!






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Let's try to figure out your current fish water quality problem before we talkle the paramaters for growing...


Your 0.25 ammonia and 0.5 nitrite reading, at first glance, says to me that something is amiss with the biological filtration.  These should really not read levels at all. There could also be something else going on, but this comes to mind first to rule out.



You mentioned that you got rid of the previous media and replace it with clay balls.  Perhaps you got rid of your biofilter?


Do you have any other medium to attract and propigate nitryfing bacteria? 


When did you do the change from gravel to clay?


What is the temperature of the water?


You mentioned a PH of 6.8.  Can you compare this to the PH of the water source and report back?

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Q.You mentioned that you got rid of the previous media and replace it with clay balls.  Perhaps you got rid of your biofilter?


What would an example of that be?


Q.When did you do the change from gravel to clay?


Before I added the new plants. About a month ago.


Q.What is the temperature of the water?


65 F. I have a heater in the aquarium. I cant adjust the settings. its automatic.


Q.You mentioned a PH of 6.8.  Can you compare this to the PH of the water source and report back?


The water source is about 7.2

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Thanks for the info.  Based on what you've said, it seems to me that a likely scenario is an uncycled biofilter.  I'd wager that guess considering the most prominent piece of information you provided: The recent change of the media, and no mention of an additional biofilter.  The only other pieces of information that could have an adverse affect, from what you mentioned, is the level of dissolved oxygen in the water, the PH of 6.8, and maybe the temperature of 65F. According to the document at the end of the email, on page, 16, "the optimum range of pH for nitrification can range from 7.0 to 9.0 (Haug and McCarty, 1972; Chen, et al., 2006)."  I'm also wondering why the PH drop from 7.2 to 6.8 in a month.  It isn't a large swing, but it makes me wonder.  Established biofilters tend to drop water PH as a byproduct of the nitrifying process I think, but all other factors assumed, this wouldnt happen in your case right now.


On temperature...traditional wisdom said that 65 might be getting on the low side for biofilter establishment.  I can't say one way or another on this, personally. The article says that temperature doesn't have as much as an adverse effect on "fixed film nitrification" biofilters, but it does not make the distinction if this affects established biofilters, or the establishment of, biofilters.  It couldn't hurt to raise the temp up a few degrees if you could manage it, in my opinion.


Also, are you putting oxygen in the water somehow?  Falling water, air stones?  I couldn't tell from your pictures.



First, I'd stop feeding the fish right now and wait it out to you get no ammonia and no nitrite readings signifying that your biofilter is indeed working with a healthy bacteria colony.  That could be a while, though.  Hopefully some remnants of the bacteria will have persisted in your system before the switch from gravel, such as on the pipe walls and other areas of the tank that will possibly speed up the full colonization of bacteria in your primary nitrification medium, your hydroton.



Next we can tackle some other issues.



P.S.  The following looks like a useful PDF of a PowerPoint presentation that gives a general overview of the operating paramaters of nitryfing biofilters.  Start on page 15



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Thank you for your reply.


I do not have a tester for chlorine or chloramine.


I do have a air pump in the tank. Pumps air in to two different hoses, One goes to about the center of the tank to a large sea shell the other goes to a strip on the wall. I also have falling water because of the flood and drain system.


Any ideas on how to raise the temp w/out buying a new heater.


Per suggestion on another forum, I stopped feeding my fish. It has been three days. I am getting the exact same readings. I also ran the pump straight for 12 hrs. Now all my plants including new growth is dying extremely quickly. I doubt they will last another day. And three more fish have died.


Any ideas on how to add needed bacteria to it. ie banana peel


Thanks for all your help

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My eyes are getting old and don't see as well as they used to.  Is your growbed sealing off the fish tank by any chance?  it looks like it' sitting flat on top of the aquarium, but I may be looking at it wrong.   As craig mentioned that  changing out the media (source of bacteria) caused you to have to start over for cycling.  I know Fritzyme is used to inoculate the bacterai and get it growing faster, but from your readings, It looks like that is happening and it's just going to take time.


I've had poor luck with buying fish from pet stores and having them die up to 50% or so has been a common occurrence especially with gold fish.


The bacteria that fully convert fish food to plant food take a while to establish, so it really is best to start with just a green leafy plant and then add tomatoes and such after the system is running steadily for a few months.   I always had to supplement with a gravel bed, generally Epsom salt and potassium chloride.  For your size system(very similar to my first ones)  I would use a tablespoon of each.   The salt may help your fish, though tetra's are a very sensitive fish from my understanding, so I can't guarantee it won't hurt them. I just don't know enough about them..


If you don't know whether your water is chlorinated or how to test it, I would treat it as if it is chlorinated and use a dechlorinating agent safe for food fish.  I use a 500 mg vitamin c pill to a 5 gallon bucket and let it sit till it dissolves and is stirred in well with the water.


So , sorry your having trouble, let's see if we can help you turn it around.

Edited by Ravnis (see edit history)

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Q.You mentioned that you got rid of the previous media and replace it with clay balls.  Perhaps you got rid of your biofilter?


What would an example of that be?



I just realized you asked me this question. Are you asking me what an example of a biofilter is?

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