Help! Bottomed out nitrates and bad algae!

CarleyCarter4 · Jan 23, 2026

Hi!

We've had this 100g saltwater tank for several years and it used to be thriving, with good coral growth. However, I just recently had a baby and my husband started his own company... so the tank has been neglected for the past 5-6 months. It's gotten so bad that most of the LPS corals have died, I had to move a couple anemones into a smaller tank that we have that seems to be more stable.

A few days ago I tested the parameters (using hanna checkers) and these were the results:

Ammonia - Couldn't test this round due to expired reagents (ordered more)
Nitrite - 7 ppb
Nitrate - 0 ppm
Phosphate - .06 ppm
Alkalinity - 10.7 dKh
Calcium - 587 ppm
Magnesium - 1800+ ppm
pH - 8.0
Salinity - 1.023

I suspected the issue was the bottomed out nitrates, so I ordered NeoPhos, NeoNitrate and Biofuel and started dosing once a day. I also increased the feedings. I then completed a 20 gallon water change, waited a day and tested the parameters again and these were the results:

Ammonia - .08 ppm
Nitrite - 6 ppb
Nitrate - 0 ppm
Phosphate - .02 ppm
Alkalinity - 8.6 dKh
Calcium - 449 ppm
Magnesium - 1800+ ppm
pH - 8.1
Salinity - 1.023

As you can see, nitrates are still bottomed out. After doing some reading, I feel like the main issue is the nuisance algae that's consuming all the nitrates. Do you think the algae is red cyanobacteria? or something else? I'd really appreciate any tips or insights on how to resolve this issue. We've probably lost over a thousand dollars in coral the last 2 weeks or so. I also want to note that in the past when the tank was doing well the phosphates and nitrates were really high.

I've attached a few pictures that I just took of the tank... the best I could do as it's nighttime, my husband who is the only one with access to control the lights is sleeping annd having any lights on in the living room caused a bad glare. So using the flash on my phone was the next best option! haha I can upload more better pictures tomorrow.

Ziggy17 · Jan 23, 2026

Just a suggestion. If it was me, in your current situation, I’d just remove the few coral that are alive and go FOWLER until the baby life slows down or your husband has more time. From the pics, it doesn’t seem like there’s a lot of coral left, so perhaps a FOWLER is better suited for you at the moment.

Stevorino · Jan 23, 2026

From the pics, it looks like an unmatured tank fighting ugly stage.

If it were me:

- Suck out all the crap you can
- Kill the lights 3-5 days
- Feed heavy, aiming to get Nitrate over 10 and Phosphate over .1
- Post pics in another week

CarleyCarter4 · Jan 23, 2026

Stevorino said:
From the pics, it looks like an unmatured tank fighting ugly stage.

If it were me:

- Suck out all the crap you can
- Kill the lights 3-5 days
- Feed heavy, aiming to get Nitrate over 10 and Phosphate over .1
- Post pics in another week

The tank has been up and running for 4-5 years now! I will your tips though, thanks!

higher99 · Jan 23, 2026

Good luck! My nano tank is fighting off an ugly stage right now too. I suspect the cause of it is that my tank is too clean and there's no spare nutrients.