I'm two and a half weeks into my Walstad setup, the first ever tank I decided to do. Since about week and a half ago I've been measuring about 2ppm nitrites. I tried to do a lot of water changes with effectively no positive result. Now diatoms started to spread over the leaves of my plants like crazy and I'm a little bit afraid they will kill my plants. I'm starting to think that the frequent water changes might have been harmful. NH4 is 0, NO3 is between 15-30ppm. I haven't been feeding the tank because i have no idea how much fish flakes am I supposed to add. Actually, I tried once a few days ago and the remains of some of the flakes are still floating on the surface and a few are rotting at the bottom.
The tank is a 16.5 gallon.
My soil is 1:1 mixture of a generic organic potting soil and vermicompost.
Tapwater GH and KH are at 11. PH is 7.2. After a few days in the tank the PH increased to 7.7.
I use a single 24w T5HO with photo-period of 5on - 4off - 5on - 10off.
Water temperature is set to 79F.
Here is my log:
Day -4: Tank set up, added soil, gravel topped off with water.
Day -3: 90% wc (panicking because a lot water bubbles on the surface)
Day -2: added filter with activated carbon for 24hrs
Day -1: Yellow water. Removed filter, 90% wc
Day 0: Added plants, 90% wc
Day 1: Tested water, zeroes across the board
Day 6: a lot of detritus worms appeared in the tank (Can't get rid of them, even after so many water changes, sucking them away with a siphon there are still is so many. I get rid of a huge number with every water change and the next day they are back, as if I didn't do anything)
Day 7: found a white fungus on the suction cup of my thermometer, the worms were feeding off of it. Cleaned it in hot water and put it back in.
Biofilm at the surface.
Measured 15ppm NO3, 0.05-0.1 NH4, and NO2 off the charts, Ph 7.7
Day 8: 50% wc
Day 9: 30ppm NO3 (wtf???), NO2 still off the charts, no NH4
Day 10: 50% wc
Day 11: 15-30ppm NO3, I learned I could test a 1:5 mixture with tap water for NO2 and this way I found there were about 1.5-2ppm, no NH4
Discovered some very small snails - MAD, because I put so much effort into desinfecting the plants.
First signs of diatoms on the front glass.
A few spiderweb-like threads on the hair grass- could only see them because they trapped some of the air bubbles escaping the substrate.
Day 12: 15-30ppm NO3, 2 ppm NO2; 25%wc
Day 13: 25% wc
Day 14: 15ppm NO3, 1.5-2ppm NO2, no NH4
Diatoms spread to plant leaves.
White fungus on suction cup again.
Added fish flakes.
Day 15: No2 no change, NH4 0, over 6ppm SiO2 - I read somewhere that diatoms feed of silicates so I tested the tank water
Added Hornwort, removed most of Najas guadalupensis - they were rotting.
Day 16: Water a bit cloudy.
Day 17:15-30 NO3, NO2 no change, 0 NH4
Some of my plants are growing well (like water sprite, egaria densa and ludwigia), some are growing somewhat (bacopa, water wisteria), some don't do anything (crypts) and some are rotting (Najas, rotala is both growing and rotting).
Also my frogbit is not doing too well. Its new leaves were always white if i remember correctly then turned a bit more green with time. But now they are rotting away. Could it be due to the frequent water changes? I'll add a pic for reference.
The small snails don't seem to care that there is such a high amount of nitrites. The are feeding off of the diatoms but the diatoms are spreading too fast for the snails to control it. And I can't add anything to deal with it because of the nitrites.
Do you have any advice about the nitrites, diatoms, detritus worms or anything else that would help with this situation? Any should do's, or should not do's? Perhaps I could add a Nerite if the small snails are ok with high nitrites? https://imgur.com/a/c4F4Ob8 https://imgur.com/a/FBowosE https://imgur.com/a/AsNNzhU