Can removing pea soup algae break the nitrogen cycle?

[arpunk]

Took over an abandoned pond 10x15x1.5-2 in my apartment building that has had fish in it but no circulation and the greenest water possible for the past ten years. Got the waterfall and skimmer back up, 4 matala mats in the biofalls (green/blue/blue/grey) and bioballs. This was a little over a month ago.

A week or so ago I used quilt batting to get rid of a lot of the pea soup algae. I was also probably overfeeding for the last week or so.

Woke up a few days ago and there was a dead fish. Tested the water and ammonia ~.5 and nitrite ~1. pH seems to hover between 6.5 and 7.5. Ammonia has been dropping but nitrite doesn’t seem to be.

Does it make more sense that it was the algae removal or the overfeeding? Could I have stalled the nitrogen cycle? Should I see if there is a buildup of sludge in the biofalls? I don’t want to disturb the bacteria unnecessarily.

Some fish are acting completely normal but others are staying at the top or staying at the bottom. Before I did anything to the pond, I’d see fish at the surface all the time and there was probably about 35 goldfish in there when I started working on it so they’re definitely fighters but that may have just been low oxygen because I had 0 nitrites a few weeks ago.

I’m just very overwhelmed and confused and everyone has conflicting advice. Any help is appreciated.

 

[GBBUDD]

no you have not yet established a balance thus you have the pea soup.

 

[WaterGardener]

Have you tested the KH? At 6.5 the pH is swinging into the acidic level which would indicate the KH is too low. It is also swinging too much. A small change from morning to evening is normal, but that it a big change and is very stressful for the fish.

Beneficial bacteria has a difficult time growing in acidic water, so it will take longer to cycle. There is also the risk of a pH crash where the pH falls drastically, killing all the bacteria and the fish.

Check the KH and add baking soda if it needs to be raised. That will raise the pH and stabilize it. You want to do that gradually. KH should be no less than 100 and even higher is no problem.

 

[RMaynard]

Use prime or similar to bind the ammonia and nitrite before raising the PH!

 

[Mgessert]

That‘s a toxic level of nitrite, so I would stop feeding and do a daily 20% water change until the nitrite is zero. Also, add some rather large plants into the pond itself to compete with the algae. It will get better with time.

 

[Mmathis]

As ammonia is dropping, nitrites will rise, then they will go down and nitrates may or may not show up (nitrates are OK, and you may or may not see a change there.)

In my first year of keeping a pond, I was learning about the nitrogen cycle, so I tested EVERY DAY for forever how long it took for the cycle to be complete. My fish load was very small, so my numbers were small, but the changes were enough that I was able to WITNESS the ”cycle” taking place — it was cool! I plotted it on a graph! Science in action!

I can’t quote the types of bacteria, but there is a different group of bacteria that do the conversions from one chemical to the other.