Ammonia won't go down and stay down.

mamalerner

I started my 70 gallon tank in August, went through the cycling, was doing weekly 20% water changes and things were great. I had (yes had) 5 giant danios, 2 Platy, 5 serpea tetras and a black molly and they seemed really happy.

I check my water about every other day. Well, we had an electric outage for a few days and they started dying. By the time we had our power back, everyone but 4 of the tetras had died. I did several partial 25% water changes and the ammonia and nitrates were through the roof so I figured my guys were in trouble anyway so did a 50% water change one day and a 75% water change the next. I stocked the filters with Cycle. I have a biowheel 400 and checked each 5 gallon bucket I put into the tank and the water was perfectly clear of ammonia.

The nitrates are gone and the ammonia showed minimal yesterday but today ammonia is through the roof. I do have a lovely bacteria bloom happening so I assumed the ammonia would start to go down, not up.My water is extremely acidic so when I do water changes I add easy balance in addition to the conditioner and stress solution. The tetras are eating and acting ok but I do not understand how to manage this ammonia problem and certainly do not want to add any fish until I can understand what is going on. I have read that acidic water is hard to raise the ph but the fish can handle a higher ammonia level in an acidic tank.

I thought conditions in a larger tank were supposed to change slowly. I went from no ammonia to 8 in 24 hours?

HELP! What did you end up doing?

Byron

Welcome to Tropical Fish Keeping forum.

When the power was out, the nitrifying bacteria in the filter went into "hibernation" of a sort, and unfortunately were very likely killed off by the de-nitrifying bacteria. Rather than explain this aspect, I'll refer you to my article:
Bacteria in the Freshwater Aquarium

Ammonia then increased. Fortunately, the water being acidic means the ammonia is changed into ammonium which is basically harmless. Provided the water remains below pH 7 this will not change. I am assuming your tap water is not basic, or such massive water changes would raise the pH above 7 in the tank and that would likely be it for the fish.

The fish are still producing ammonia, as is the breakdown of organics by bacteria in the substrate, so it will continue to rise. In acidic water it takes longer for the nitrosomonas bacteria to multiply. This too is explained in the linked article.

No mention is made of live plants, so I will assume you do not have any in this tank. They would have helped considerably by assimilating ammonia/ammonium as their preferred source of nitrogen. You would likely not even detect ammonia in a power outage, provided the plants were still able to photosynthesize of course.

Byron.

Calmwaters

Mamlerner I have nothing to add but I wanted to say welcome to the forum and I am sorry about your fish.

mamalerner

I would just like to make sure I am getting the correct message so please bear with my ignorance.

Is the gist of all that you shared that with the very low ph of my well water, it will be hard to grow and maintain an effective bacteria balance to deal with the ammonia produced by my fish? Using the ammonia test drops is useless because the acidic water binds the bad ammonia to become ammonium, which the drops cannot distinguish. Adding AmmoLock can also skew the ammonia test.

Would plantings and weekly 25% water change probably be adequate or should I do more or less or something else? How many and what sort of plants should I start with for a 70 gallon tank? I just bought a new light because the old one blew in the power outage so I made sure to get a lamp that was specific for aquarium plants.

Should I add a sponge filter to the tank?

Thank you again for your quick response yesterday. It took me a while to read everything and try to digest it.

...and thanks for the kind thought Amanda.

Byron

Generally speaking, yes, but this is not problematic. As I mentioned in that linked article, the lower the pH the slower nitrifying bacteria will function, to the point of not functioning at all around pH 6. Several of my tanks are in the pH 5-6 range, but I have no ammonia or nitrite issues because the ammonia changes into ammonium and the plants assimilate the majority. With minimal (if any) nitrosomonas bacteria, nitrite is scarcely being produced, and of course nitrates are also at zero. There is thus no detriment to the fish from ammonia. The only issue here is whether or not the fish species can manage in a low pH, but that is another issue entirely.

And yes, most of our test kits do not distinguish between ammonia and ammonium, so "ammonia" is whichever is present. I never bother testing for ammonia or nitrite, since with my very soft and acidic water plus having the tanks well planted, I have no concern over these.

Depending upon the fish load, weekly water changes can be from 25-50% of the tank volume. I do 50-60% every week and have done for 15 years. I like to stock my tanks. And the water change is dealing with "crud" that is not measurable by any test and can only be removed by water changes. Urine, dissolved solid waste, fish pheromones and plant allelopathic chemicals all make up "crud." No filter is capable of handling these. Plants can, sort of, but minimally and only if the tank is very lightly stocked.

What is the tube? I may have suggestions to replace it when I know this. Some "aquarium" or "plant" tubes are actually not as good because they are very weak intensity; a full spectrum or daylight tube works better.

On its own, a sponge filter is adequate in a smallish well-planted tank. But on a larger tank like a 70g, I would go with a good canister filter. This will give more flow down the tank and that is important for the fish and plants. What filter have you now?

Byron.