Ugly Phase or Early Stage Apocalypse?

[Dr. D]

I'm not at all freaked out by an ugly stage, but I want to make sure I'm not battling dinos or some other nasty critters. I had what I assumed were diatoms for a few weeks, nothing too bad. But recently the color is a much darker brown, and on everything, even snail shells. I also have what I assume is hair algae, most visible in the pic of the "mountaintop." My Foxface sure likes it, but there's way too much for him. (I have ordered a basic microscope to help diagnose.) Here are some pics, followed by a summary of the tank and recent parameters:

• 100gDT, 33g sump
• ~10 week old tank
• Started with dry rock (15 lbs of TBS live rock coming next week; wish I'd started with that)
• Cycled successfully weeks ago with Dr. Tim's and Fritz Turbo, thanks to advice here
• Started with 3 (now 2) clowns and 4 (now 2) Banggais after cycling
• Added two rounds of Dinkins pods and feed phyto every day
• Added 8 LPS corals a couple of weeks ago; they seem happy
• Added 4" Foxface, 2" Hippo tang, 7 (now 5) Chromis, goby & CUC ~ two weeks ago - fish seem happy
• Reefmat 500 running 24/7
• Ultra Reef skimmer - running 24/7 (dry)
• Plank feeder; was feeding 3x/day/40 seconds, Avast Reef Jerky; after adding the new fish, switched to 8x/day/20 seconds because I thought it would be better for Chromis; now not sure what to do because I don't know if overfeeding is one of my problems; usually add 1 cube frozen every day
• Weekly 15% water changes

My CUC included the usual mix of snails and hermit crabs. They were doing great at first, but many of my hermits and snails seem to have died, which surprises me because I thought there was plenty for them to eat. Here's recent testing, all from Hanna checkers:

	3/6/2025​	3/16/2025​	3/21/2025​	3/22/2025​
Alkalinity	5.5​	16.9​	7.5​	7.3​
Phosphate (ppm)	0.16​	0.14​	0​	0.02​
Nitrate LR	>5​	NA​	>5​	NA​
Ammonia	0.08​	NA​	0​	0​
Calcium	496​	520​	NA​	NA​
Salinity	1.024​	1.025​	1.024​	1.024​

I was surprised to see phosphates drop so low, and worry it's a sign of dinos. My Nitrate test is low range, so all I know is they're above 5. (Is there a better way to test Nitrates? I don't see a HR Hanna checker on their site.)

I'm confused about whether I should lessen my skimming/filtration, whether sodium phosphate dosing is necessary, and whether anything else looks concerning to you. I also wonder if the stuff on the black glass may be coraline algae, Thanks!

 

[Uncle99]

I'm not at all freaked out by an ugly stage, but I want to make sure I'm not battling dinos or some other nasty critters. I had what I assumed were diatoms for a few weeks, nothing too bad. But recently the color is a much darker brown, and on everything, even snail shells. I also have what I assume is hair algae, most visible in the pic of the "mountaintop." My Foxface sure likes it, but there's way too much for him. (I have ordered a basic microscope to help diagnose.) Here are some pics, followed by a summary of the tank and recent parameters:

• 100gDT, 33g sump
• ~10 week old tank
• Started with dry rock (15 lbs of TBS live rock coming next week; wish I'd started with that)
• Cycled successfully weeks ago with Dr. Tim's and Fritz Turbo, thanks to advice here
• Started with 3 (now 2) clowns and 4 (now 2) Banggais after cycling
• Added two rounds of Dinkins pods and feed phyto every day
• Added 8 LPS corals a couple of weeks ago; they seem happy
• Added 4" Foxface, 2" Hippo tang, 7 (now 5) Chromis, goby & CUC ~ two weeks ago - fish seem happy
• Reefmat 500 running 24/7
• Ultra Reef skimmer - running 24/7 (dry)
• Plank feeder; was feeding 3x/day/40 seconds, Avast Reef Jerky; after adding the new fish, switched to 8x/day/20 seconds because I thought it would be better for Chromis; now not sure what to do because I don't know if overfeeding is one of my problems; usually add 1 cube frozen every day
• Weekly 15% water changes

My CUC included the usual mix of snails and hermit crabs. They were doing great at first, but many of my hermits and snails seem to have died, which surprises me because I thought there was plenty for them to eat. Here's recent testing, all from Hanna checkers:

	3/6/2025​	3/16/2025​	3/21/2025​	3/22/2025​
Alkalinity	5.5​	16.9​	7.5​	7.3​
Phosphate (ppm)	0.16​	0.14​	0​	0.2​
Nitrate LR	>5​	NA​	>5​	NA​
Ammonia	0.08​	NA​	0​	0​
Calcium	496​	520​	NA​	NA​
Salinity	1.024​	1.025​	1.024​	1.024​

I was surprised to see phosphates drop so low, and worry it's a sign of dinos. My Nitrate test is low range, so all I know is they're above 5. (Is there a better way to test Nitrates? I don't see a HR Hanna checker on their site.)

I'm confused about whether I should lessen my skimming/filtration, whether sodium phosphate dosing is necessary, and whether anything else looks concerning to you. I also wonder if the stuff on the black glass may be coraline algae, Thanks!

I’m seeing pest type algae and bacteria, maybe not unnormal for 10 weeks, plus you got a big load on that immature environment.

You post nitrate as greater than 5…..how much greater?

 

[exnisstech]

I'm confused about whether I should lessen my skimming/filtration, whether sodium phosphate dosing is necessary, and whether anything else looks concerning to you. I also wonder if the stuff on the black glass may be coraline algae, Thanks!

HI782 is the high range tester. Its the one most people use. Its much easier than the LR. Just a pack a reagent similar to the PO4 tester.

 

[Dr. D]

I’m seeing pest type algae and bacteria, maybe not unnormal for 10 weeks, plus you got a big load on that immature environment.

You post nitrate as greater than 5…..how much greater?

I don't know. I will soon:

HI782 is the high range tester. Its the one most people use. Its much easier than the LR. Just a pack a reagent similar to the PO4 tester.

Ah... not sure how I missed that. Hanna has a 15% off sale and free shipping now, I'll order one.

 

[Dr. D]

I’m seeing pest type algae and bacteria, maybe not unnormal for 10 weeks, plus you got a big load on that immature environment.

That's very encouraging. What do you recommend I do with the skimmer and Reefmat? Am I filtering too much (and thus the low phosphate)?

 

[BryanM]

This must be the 2nd thread on this as I swear I already replied once :o

Microscope is the only tried and true way to know what that brown algae is. I will say that's what my dinos look like. If phos really reached 0 (I think that's likely a test error), then it would lead me more to dinos.

In any case I would siphon it out through a filter sock and put the water back in the tank.

Does it go away at night?

 

[Dr. D]

This must be the 2nd thread on this as I swear I already replied once :eek:

Microscope is the only tried and true way to know what that brown algae is. I will say that's what my dinos look like. If phos really reached 0 (I think that's likely a test error), then it would lead me more to dinos.

In any case I would siphon it out through a filter sock and put the water back in the tank.

Does it go away at night?

LOL you did. I posted my own thread here because I felt I was hijacking someone else's thread (and said so on that thread). Thank you twice! I retested today and got 0.02 (my original post incorrectly said 0.2) phosphates, so not likely a testing error, unfortunately. Microscope on the way. I will look tonight after lights out.

 

[mboley]

Basically you have too much light too soon making your ugly stage uglier. I have a 75 gallon tank 4 months in and I just recently turned my lights on at a very low level. And that's even though I added some live rock and sand from another tank.
I have four fish and threw in a few soft corals in there just for something to look at and I only feed the fish once a day. My rocks have just recently turned a light brown and diatoms are starting to show up. I just added five snails and five hermits this week because there wasn't enough for them to eat.

Your N and P are great for a tank so young though. Patience is your friend in this hobby.

 

[Slocke]

Put filter floss in high flow areas, clean or replace 1-2 times per day. Will take a few months but it works great

 

[Dr. D]

Basically you have too much light too soon making your ugly stage uglier. I have a 75 gallon tank 4 months in and I just recently turned my lights on at a very low level. And that's even though I added some live rock and sand from another tank.
I have four fish and threw in a few soft corals in there just for something to look at and I only feed the fish once a day. My rocks have just recently turned a light brown and diatoms are starting to show up. I just added five snails and five hermits this week because there wasn't enough for them to eat.

Your N and P are great for a tank so young though. Patience is your friend in this hobby.

Thanks. I told myself I'd go really slow, and did keep the lights completely off for 8 weeks or so. But then I got the coral bug, and became a complete hypocrite.

 

[Dr. D]

Put filter floss in high flow areas, clean or replace 1-2 times per day. Will take a few months but it works great

Thanks. I'll try that too.

 

[Dr. D]

Your N and P are great for a tank so young though. Patience is your friend in this hobby.

I made a typo in the original post (corrected now). My latest Phosphate reading was 0.02, not 0.2, confirming yesterday's 0 reading.

 

[mboley]

I made a typo in the original post (corrected now). My latest Phosphate reading was 0.02, not 0.2, confirming yesterday's 0 reading.

That's too low, I would add some phosphates. It is a good sign that your N and P are so low already. You have the opposite problem most experience.

 

[Dr. D]

The brown plague doesn’t seem to disappear when it’s dark.

 

[NDFoz]

Thanks. I told myself I'd go really slow, and did keep the lights completely off for 8 weeks or so. But then I got the coral bug, and became a complete hypocrite.

I am literally in that same spot you’re. My PO4 bottomed out to unreadable verified running 2x on my Hanna’s and my Salty LFS used that new fancy Hanna Tester. I lowered my lights down and purchased a Sicce UV-C Sterilizer and started dosing MicroBacter7 and HydroSpace PNS Deep Cycle and also dropped 2x jars of Galaxy Pods from Algae Barn (usually add a jar of 5280 Pods each month). The nasty slime looking stuff is slowly going away. My filter roller has gone through an entire roll of paper in 2 weeks and that stuff was NASTY! Oh and the smell is awful! But it’ll pass.

 

[Dr. D]

Thanks. I told myself I'd go really slow, and did keep the lights completely off for 8 weeks or so. But then I got the coral bug, and became a complete hypocrite.

I am literally in that same spot you’re. My PO4 bottomed out to unreadable verified running 2x on my Hanna’s and my Salty LFS used that new fancy Hanna Tester. I lowered my lights down and purchased a Sicce UV-C Sterilizer and started dosing MicroBacter7 and HydroSpace PNS Deep Cycle and also dropped 2x jars of Galaxy Pods from Algae Barn (usually add a jar of 5280 Pods each month). The nasty slime looking stuff is slowly going away. My filter roller has gone through an entire roll of paper in 2 weeks and that stuff was NASTY! Oh and the smell is awful! But it’ll pass.

So high filtration is good?

 

[NDFoz]

So high filtration is good?

I’ve been reading nonstop for the last two weeks on this stage and that is what everyone says. Stay on top of filtration at all times. I’ve legit ordered another dozen rolls of filter paper.

 

[Eric R.]

Looks like dinos. Microscope will help with ID and treatment method.

 

[NDFoz]

So high filtration is good?

Here is the roll i replaced this afternoon. When this hit I was using 1 roll every 6 weeks. Now a roll every 2 weeks or less.

 

[Dr. D]

Thank you. On it.