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I build a 170 gallon tank with a sump and 2 grow beds.  Media is PlantIt.  It is in the basement and is being heated.  The temperature hangs around 75 degrees F.  I have been trying to get this cycled since April and have never been able to register nitrites or nitrates.  For some reason I have a hard time keeping the PH up over 7.0.  I understand that it will drop over time once the bacteria are established but if my grow media is inert why would I have issues keeping the PH up before I have ever been able to register nitrites.  

A little more background, I was fishless cycling but became so bored with no results I put 3 large crappie into the system.  They have been alive in there for close to a week and I have watched the ammonia levels keep rising.  They are around 6ppm or greater now.

Any ideas what might be wrong with my system.  Maybe it's not the system and it's just ME!!! This is so frustrating after working so hard on building the system and dropping quite a bit of money on it as well.



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Hi Steve,

A couple of questions.....What was the ammonia level you kept the system at when you were fishless cycling? Do you have plants in your growbeds? Thanks!


What did you begin adding ammonia with and in what quantity? What has your ammonia readings been since adding the fish? Are the crappie eating well?

What are your circulation and aeration rates?

Casey Haas said:

Hi Steve,

A couple of questions.....What was the ammonia level you kept the system at when you were fishless cycling? Do you have plants in your growbeds? Thanks!

Casey - Ammonia has been between 2 and 4 ppm.  I had planted a measly chive plant and some lettuce but turned the grow light off weeks ago.  It was hard to justify the power usage for me since I couldn't measure anything happening.  Should I turn the grow lights back on and plant the system?

Glenn - I used a powder ammonia from a cycling kit I bought from the Aquaponic Source.  I don't recall exactly (am away from home) but I believe it was several teaspoons that I used.  I originally got the ammonia to high and ended up draining it and starting over but that has been well over a month ago now.  I have never calculated my circulation rate but I would say the bell siphon fires every 12 minutes or so.  I added an air stone about a month ago as well but I don't know how to calculate an aeration rate.  The crappie have not started eating but I have read that getting them to start pellet feeding can be hit or miss.

Hope that info is enough to be helpful.  Thanks for jumping in and trying to help.

Any chance you might have chlorine or chloramines in your water? Municipal water supplies tend to have that kind of stuff in it. It's used as a disinfectant which basically kills all the bacteria you're trying to cultivate in your system. Chlorine will off-gass over a short period of time, but chloramines don't.

Bacteria will take quite some time to colonize if the PH is under 7 and there is not sufficient oxygenation of the media (flood and drain not running 24/7) Try to get the PH up to the 8 range when cycling which is what the bacteria like. Your plants may not like it but short term pain for the long term gain.

I have also used Plant It and read from another post that it may have sulfur that can leach from it which will send your PH down.  My solution is to buy 4 pounds of shell grit off Ebay, go to Lowes and pick up a paint strainer bag to put the shell grit in and then place the grit where the water flows over it. This has slowed the rate of drop on new media, I then use calcium hydroxide and potassium bicarbonate daily to manage the ph in the 7.4 7.8 range. The good news is that the effect of the sulfur will lessen over time. Older plantit media I am using in another system does not drop as much as the new stuff.

Alex Veidel said:

Any chance you might have chlorine or chloramines in your water? Municipal water supplies tend to have that kind of stuff in it. It's used as a disinfectant which basically kills all the bacteria you're trying to cultivate in your system. Chlorine will off-gass over a short period of time, but chloramines don't.

I contacted the municipality that provides my water and they say that they don't treat our water with chloramines.  Is there a test kit for chloramines?

There was definitely chlorine out of the tap.  Plenty of time has elapsed for it to have off gassed by now though.

Ok I will work on getting the PH up.  It is good to know about the PlantIt.  Disappointing but definitely good to know that it can impact PH.  

I happen to have a bag of crushed Oyster Shells at home that I use for my quail.  I looked up shell grit and it appears they are interchangable for this purposes.  Now I'm off to grab a paint strainer bag.  Again, thanks for everybody's help so far.

It does seem odd that your system hasn't cycled yet, especially at that temperature, but stranger things have happened.

Keeping the pH up is definitely worth a try although my pH started dropping after the first week of fishless cycling and my system cycled below pH 7 without any trouble  (it was outdoors though...maybe it's harder to attract nitrifying bacteria in a basement?). Do you know someone in your area with a system that you could scrape some slime from? That might help get things going. Be aware that the shell grit won't keep your system above pH 7 (and in full production mode not even that) and is very slow acting because it only really dissolves below pH 7 and not at a fast enough rate to keep up with nitrification once it gets going. You would probably be better off using a combination of potassium  carbonate and calcium carbonate to bring the pH up. Carbonates may also help with getting the cycle going as it seems the bacteria do need a minimum amount of carbonates to function (kH above 40). I have also had success with bringing the pH in my system up with partial water changes with de-chlorinated  high pH/ high carbonate tap water (10% change), which also seems to refresh things in the system. I do this once or twice a week depending on the need.

Another idea is to add some potassium to the system. The bacteria need potassium for metabolism and I found that adding potassium really revs up my biofilter. The potassium level in tap water (at least mine anyway) does not appear to be sufficient. You can add this as potassium carbonate or potassium hydroxide (both of which will bring pH up) or as potassium sulfate (which will not affect your pH).

The fact that your ammonia level is at 6 ppm is scary for your fish. They may not make it. I would suggest salting your system to reduce stress and to prevent brown blood disease if they survive the ammonia spike only to get hit by the nitrite spike. I have no experience with crappie so I don't know how tolerant of salt they are. Maybe try aquarium salt at 3 parts per thousand and see how they handle that. You can increase the salt to 6 parts per thousand if the crappie are salt tolerant. You apparently need six times the amount of Cl- ions to outcompete every NO2- ion to prevent brown blood disease. Check out this article You may not be able to achieve that level based on the salt tolerance level of your fish, but you can hopefully get close. I probably wouldn't feed them for a while in any case. Something else to consider....raising your pH too much will make your ammonia level toxic to your fish (if it isn't already). Check out any aquarium ammonia toxicity chart on the web to see how pH, temperature, and ammonia levels interact to be either "toxic" or "nontoxic" to your fish.

I have both Hydroton and Plant It in my system and have not had any problems with pH issues as a result. I think the nitrification process in just so carbonate intensive that even the very beginnings of the process result in pH decreases. I read somewhere that every one part of ammonia converted through the nitrogen cycle requires something like six parts carbonate (don't quote me on that though). I am just using it as an example to illustrate that the process can naturally drive down pH and quickly too! I saw this in my own system after week one of fishless cycling. It took six weeks to fully cycle my system.

You've got enough ammonia in your system and a good temperature, so just make sure you have enough carbonates and potassium to feed the bacteria and salt the system to hopefully save the fish. Partial water changes can help keep the ammonia and nitrate levels down to a manageable level and help keep the pH up. Just make sure to remove chlorines and chloramines first. (I have heard that if you get an ammonia reading on your tap water that you probably have chloramines but I'm not sure if that is the case or not....I am fortunate that my tap water doesn't have chloramines...yet)

Don't give up. If your case is anything like mine, this will be just the first of many frustrations associated with learning AP (it takes a while to get to the rewards, but they do come!). Just when you think you've got one thing figured out, you end up back in the books for some new problem. It isn't easy to get it right (despite what anybody tells you) and the only thing that has kept me going is annoyance that I have spent so much money on my system that I can't let it fail. ;) Of course this usually means spending more money to address each new problem which makes it sort of a vicious cycle, albeit one that keeps me motivated when I might otherwise throw in the towel. Now, after one year at it, I am expecting my first tomato soon...yay! So don't give up!

Good luck!

If your fish don't make it replace them with some cheap goldfish. They're durable and dispensable. Don't give up. Before you know it you'll be cycled and worrying about more plant space.

I have been able to raise my PH to about 7.6.  I also did a partial water change as Casey suggested.  I'm going to resume planting the system so that hopefully when cycling occurs my plants can help with the spikes.  Tonight I will start logging all of the test results again.  Thanks for all of the great information!  You guys have got me excited to tackle these problems again.  I guess that means I will be spending more money in the future on this project Casey!  ;)

My new system just finished cycling and yours will follow soon! Look for a very light brown coating on the inside of your PVC pipes... that's the Nitrosomonas and Nitrobacter setting up shop.

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