Fluctuating water parameters

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AceReject

Aquarium Advice Apprentice
Joined
Sep 9, 2021
Messages
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Hi guys. I’m having problems with my freshwater tank and am hoping someone might be able to help please. I’ve spent hours and hours researching what to do, but I’m getting nowhere.

The tank is about 8 months old. It’s 160L and heavily planted. Stocked with: rasbora, tetras, honey gourami, cherry barb, albino cories, bn pleco and otos. They’ve all been there a while and there’s been no new additions for months.

As far as I understand it, my tank was cycled. I did a fishless cycle with ammonia originally, and for months I was getting readings of 0 ammonia and 0 nitrite. The biggest challenge I have had in terms of maintaining water parameters is raising KH. The local water has no KH, and this is a problem all of the local fish stores have also. I’ve done everything they say, such as crushed oyster shells in the filter and ocean rock (I think it’s called) in the tank itself. I add “KH Up” during water changes, and get a KH of about 3 if I’m lucky. If I add any more, the pH just gets too high.

The main problem, however, is unexplained ammonia and nitrite spikes. Just recently (maybe the last month), testing was picking up occasional nitrite readings of 0.25 - 0.5, which concerned me. I’ve added Freshwater Colony to try to up the BB, and as far as I know, I’m following all the recommendations. The weird thing is that these nitrite spikes are very unpredictable. We’ve moved to doing daily testing (always with a NT Labs kit) and it really is like lucky dip. I can go maybe 6 days with no nitrite, then bam, it’s 0.5. Tank cleans and water changes are happening at least once a week, but in reality I’d say much more due to these problems. I actually feel like there is too much turnover of water, and that this is preventing the tank from settling, but I could be wrong. Yesterday, we did our weekly maintenance with a big gravel vac, and changed maybe 50% of the water. Today, we have ammonia at about 0.1 - 0.2, and nitrite maybe 0.5. It makes no sense? I’ve tested the tap water and it seems ok.

My only theory that could possibly explain the problem is dying algae. We had quite a lot of what I think is BBA, so I looked into how to remove it. I started dosing with Seachem Flourish Excel every day (exactly the dosage specified), and I noticed a lot of the algae going grey. We try to remove it as soon as possible, but it’s so stubborn to get rid of, even when seemingly dying! I feel like if I stop using the Flourish Excel, it will makes things even worse and that I just need to ride it out? But I don’t know. I’m not even sure if that is the reason. As far as I understand it, ammonia and nitrite should never go past 0 in a cycled tank, and certainly not with such frequent water changes.

I’m honestly so disillusioned and dejected. I really feel like giving up. There’s no enjoyment at all at the moment. I dread even looking at the tank for fear of the next problem.

Thank you for reading if you got this far. Does anyone have any advice they can give please? :confused:
 
It could be low KH. The nitrogen cycle uses up KH, when its gone your cycle cant operate. 7ppm KH to cycle out 1ppm ammonia i think. Your 3dKH is about 54ppm. So that would cycle out about 7ppm of ammonia before it runs unless it is being topped up.

You then do your water maintenance, buffer the KH, cycle kicks in again and your cycle re-establishes and you see the ammonia and nitrite disappear again until the KH runs out.
 
It could be low KH. The nitrogen cycle uses up KH, when its gone your cycle cant operate. 7ppm KH to cycle out 1ppm ammonia i think. Your 3dKH is about 54ppm. So that would cycle out about 7ppm of ammonia before it runs unless it is being topped up.

You then do your water maintenance, buffer the KH, cycle kicks in again and your cycle re-establishes and you see the ammonia and nitrite disappear again until the KH runs out.

Hi Aiken, thank you so much for replying!

Do you have any suggestions for how to get the KH permanently up? As I said above, I have crushed oyster shells in the filter and one piece of ocean rock in the tank, and then I use KH Up with the water changes. I find if I go any further with dosing the KH Up, the pH goes too high (I try to maintain it at about 6.5 - 7). I’m not really sure what else I can do?
 
Increasing KH will increase pH. Not much you can do about that. There are many ways to increase KH, but none that doesnt give a corresponding increase in pH.

Are you seeing the KH dropping gradually after your water maintenence, or does all those oyster shells and rock keep it steady?

Are you seeing any issues with your fish?

On the face of it, while those ammonia and nitrite parameters are a sign you arent cycled, but also arent that high and shouldn't be causing any health issues.

Is your tapwater treated? Do you know if its chlorine or chloramine? Do you have tests of your tap water?
 
Increasing KH will increase pH. Not much you can do about that. There are many ways to increase KH, but none that doesnt give a corresponding increase in pH.

Are you seeing the KH dropping gradually after your water maintenence, or does all those oyster shells and rock keep it steady?

Are you seeing any issues with your fish?

On the face of it, while those ammonia and nitrite parameters are a sign you arent cycled, but also arent that high and shouldn't be causing any health issues.

Is your tapwater treated? Do you know if its chlorine or chloramine? Do you have tests of your tap water?

Thank you! I really appreciate your help here.

I have just ordered a large bag of crushed coral, and I think I’m going to have to put a much larger quantity in the filter instead of the current crushed oyster shells.

The KH normally falls somewhere between 2 and 4. I know this is really low, and I have to be honest in saying it’s the parameter I’ve concerned myself with the least; given the difficulties I’ve had in raising it. I must admit, I thought KH was only really there to buffer the pH, and as the pH was consistently fine, I decided to just accept it as being low. Obviously, in light of what you have said, I’ll be giving it much more attention now.

The fish are all fine and seem healthy. They never show any signs of gasping for breath or having irritated gills. The only stress I’ve observed is my own. :lol:

The tap water is definitely treated. I’m not sure if it’s chlorine or chloramine though. It gets a dose of Seachem Prime in a bucket before the water change.
 
If your KH is steady between 2 and 4, that's not a problem. If its getting down to closer to zero, then it could cause issues with your cycle and cause pH drops too.

Do a test on your tap water. If its chloramine that would show as ammonia.
 
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