[lindsea]

Oh, hello!
I've been on a slow descent into aquarium madness for the past several years, starting from a feeder fish in a 5gallon mistake some 13 years ago. So, of course, I'm up to a 120gallon running and several other tanks in storage at this point. I avoided getting into planted tanks because I have a goldfish and a loach ready to dig up everything. Now in their old age (goldfish 10 years, loach 8 years), they are much more reasonable and won't go after roots if I have stones around them. I ended up with some bladder snails when I got the plants and now also have a cool assassin snail who has mostly cleared that up. I finally switched from classic fluorescent lights to a really amazing LED light system at Christmas and have absolutely wrecked my tank with algae since I don't know what I'm doing...so I have joined to learn. It's nice to meet you!

Tank hardware: 125G tank (long), Fluval FX6 filter, two bubblers, completely unnecessary eheim jager thermostat heater set for 68F but actually keeping things around 75F, Fluval Fresh and Plant 3.0 LED Light Fixture 59W, 4ft actual lights only on the right side of the tank. It's set to be on from 06:00 to 18:00 using the preset planted setting. I use pool sand as substrate and fertilize with seachem flourish tabs, but I have not added them since the first time I put any in around 2 months ago. I typically clean off the front and side walls but never the back since I don't have a cool background and I don't mind the help with nitrogen. That was before it got super gnarly though.

Plants: anubias frazeri, bunch of crytocoryne wendtii, amazon swords (echinorodus bleheri?), some hornwort just floating around, bacopa monnieri, some christmas moss if my goldfish would leave it alone, and many many regrets about causing this weird black algae everywhere? Is it BBA? Is it cyanobacteria? Is it too much light or should I look for phosphate? I guess I'll check out the algae forum to find out!

 

[rakali]

Hi. Goldfish make lots of waste which leaves nutrients around for algae. I'd add more plants. Also cycle your lights on and off during the day to give an advantage to your plants. Diana Walstad talks about it in a podcast interview on youtube. You may also want to try turning your filter off for an hour a day. AzGardens highly recommends that. Allows your plants to pull more C02. You may want to add more of a cleanup team too (snails, scuds, ottocinclus, etc.)

 

[Plinkploop]

Maybe slowly cut your lights down to 6-8 hours on? I don't know how you feel about pond snails but they can be helpful with messy fish like goldfish. My 220 goldfish/ hornpout tank is getting pretty gnarly too so I've been plucking them from another one of my tanks. The only problem is they will completely infest your tank your tank until they get their job done, then they disappear- this is my experience with them- I have heard horror stories from others, but I've never had a problem. There are many types of snails that will get the job done, possibly better, but a lot of times you can get pond snails for free at big box pet stores (if snails are legal to keep where you are) and they do the job fine. You could try adding some more plants to try to use up excess nutrients.

Depending on how big your goldies mouth is I would be cautious getting otos, if your goldfish gets curious and inhales one the barbs could get stuck and cause some major damage. I have a preference to use snails with goldfish, it just looks right to me and I have no idea why.

...there's always the option to turn off the filters and scrub and vacuum...

Good luck!!