125g 2 in 1 Seagrass Reef

ThePurple12

New member
This is the build thread for my 125g seagrass reef tank. I started it this Christmas.

Half the tank is a coral reef, and the other half is dedicated to seagrass and macroalgae.

I've started this build thread at a bad time, as the tank's going through a cyano phase, probably due to the fertilizer I added to the sandbed for the seagrass. I added the fertilizer because the seagrass wasn't doing well. I think the seagrass might be coming back, but I'm having to clean the blades off twice a day due to cyano growth. The cyano's growing on the gorgonian, too, and for some reason the bubble tip anemones are all shriveled up. As you can see, the tank's not in its prime....

Equipment:
2x blackbox LED
2x 150w metal halide
2x 1500gph Hydor Koralia powerhead (Yes, I know I need more flow!)
20g sump that currently has no real purpose
2x 150w heater

Fish:
cleaner wrasse
2 ocellaris clownfish pairs (we'll see how this plays out)
yellow watchman goby pair
engineer goby
bicolor blenny
coral beauty angelfish
female bluestripe pipefish (I'm looking for a male)

Corals:
several acroporas
orange and green montipora capricornis
mystic sunset monti
montipora spongodes(?)
candy cane coral
hammer coral
unknown zoas
purple gorgonian
7 bubbletip anemones (I know, not a coral)

Plants:
shoal grass
Johnson's grass
sargassum
codium
Gracilaria hayi
Botryocladia
cyano
 
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Can't see. No pics.

I think your grasses will come back. They take awhile to adjust to new conditions. Hang in there with the cyano. A multi-day manual removal, chemiclean treatment, 3-4 day blackout and water change combo punch is what worked for me.

A fast-growing green macro like Ulva may help soak up excess nutrients.
 
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Believe it or not, the Johnson's grass used to cover the entire sandbed. It all disapperead, and the shoal grass growth stopped. The Johnson's is recovering, though.
 
Cool tank! Looks good.

Sorry to hear your grasses are struggling. Manual removal removes the most concentrated food source-the cyano itself. So you're on the right track.
 
Can't see. No pics.

I think your grasses will come back. They take awhile to adjust to new conditions. Hang in there with the cyano. A multi-day manual removal, chemiclean treatment, 3-4 day blackout and water change combo punch is what worked for me.

A fast-growing green macro like Ulva may help soak up excess nutrients.

Thanks, I think the grasses are recovering.

I've found that cyano will go away on its own with proper conditions. But speaking of Ulva, I discovered a tiny little macro that looks like ulva growing on the base of the gorgonian.
 
I call this "Macro Mountain"! It's surrounded by Gracilaria hayi, there's a patch of codium, and sargassum and a gorgonian on top.

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I found that Codium does best in bright light, among the grasses. Also it likes cooler temps, like below 80. Your macro mountain is nice. Sargassum is very challenging so congrats to you!
 
I rearranged the rockwork on the reef side, it looks much better now:
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The Johnson's grass is definitely coming back now, adding the rose fertilizer really worked. I see new leaves every 2 or 3 days. Soon it'll be back to covering the whole sandbed!
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I think I know why there's so much cyano. My phosphate's at .25!

Today I got some Spectracide Stump Remover (KNO3) from Lowe's for $6. Using a calculator, I added enough to raise nitrates from 1 to 5. I read in an old thread that adding more nitrate to balance phosphate will help the seagrass grow faster (or, in my case, start growing again), therefore lowering phosphate and killing cyano.
 
Nice rock work! Glad to hear your johnson's grass is coming back. Good call on the potassium nitrate too. Looking' good!
 
The tank's coming along! The 2 clowns almost imediately ditched their bubble tips and moved into the new magnifica anemone I got, and they hardly ever leave it.

As for the planted side, the nitrate dosing definitely seems to be working. I think the shoal grass might be improving. The leaves aren't dying off so much anymore and the cyano's slowed down, but I haven't seen any new plants yet. Johnson's is growing, but not as fast as it probably should be.

The tank went through 25 ppm of nitrate in less than a week! The macros are growing like crazy. The sargassum reached the surface a while ago, and the gracilaria's in serious need of a trim.
 
Sounds good! I often thought that my rapidly growing macros were outcompeting my grasses for nutrients. You may be having the same thing. I think it helps to prune the macros back, essentially making them a smaller mouth to feed.

It seems like seagrasses take a lot longer to get established than they should. Hang in there and keep trying to find the conditions they flourish in.
 
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