Freshwater meets Saltwater, experimental macroalgae tank

[Diastro]

Hello everyone! I have decided to dip my hands into the saltwater side of the hobby, with a twist! Something that has always kept me from saltwater tanks was a combination of the cost, the difficulty, and especially the traditional blue lights.

Recently however, I discovered macroalgae tanks! I instantly fell in love. It combined everything I loved from freshwater into a new challenge for me as a fish keeper.

Here is now it's going so far.

As you can see this is definitely not a traditional reef. I have decided to try to make this tank as cheaply as possible while being as similar to a freshwater tank as I can make it.

For the rockwork, I have chosen to use red lava rock chunks, for the sand I am using a cheap home Depot sand, and I have added several pieces of driftwood to the tank. Very unconventional, but I love how it looks.

Here is a picture of the scape progress when I first started.

I was really happy with this scape but it had to be modified because I found a glass anemone on one of the rocks and decided to pull it out and soak it in hot fresh water. Thanks lfs!

Photo of the cool driftwood I bought.

Here is the sand I got. I wanted a more natural look so I opted for this pavestone patio paver sand. It is full of gravel though so I spent some time sifting it. And a lot more time rinsing it. Not the typical sand you would see in a saltwater tank but the price is unbeatable and I had a bunch left over from my previous tank.

So far neither the sand nor the driftwood has had a negative affect on the tank. More to come!
Here's a cute hitchhiking snail! You can see the sand result up close as well.

 

[Devaji]

I was wondering when some one would try this.
I would be worried about high silicate in the sand you used.

TBS has a ocen direct sand you might fancy if you do have to pull it.

lava rocks are not used in SW either. I believe something about leaching Iron? IDK I could be wrong. but there is a reason I just forget. it's a bummer too as laval rock is 100 X cheaper than the rock we use.

anyway keep us posted i am curious to see how this pan out.

 

[Diastro]

I was wondering when some one would try this.
I would be worried about high silicate in the sand you used.

TBS has a ocen direct sand you might fancy if you do have to pull it.

lava rocks are not used in SW either. I believe something about leaching Iron? IDK I could be wrong. but there is a reason I just forget. it's a bummer too as laval rock is 100 X cheaper than the rock we use.

anyway keep us posted i am curious to see how this pan out.

It's true that lava rocks are avoided due to the fear of iron leaching into the tank from them. However macroalgaes use iron for their growth, so I am not concerned by any leeching small or large.

Right now the nutrients are super high in the tank, but as the macro starts to consume them I will be dosing fertilizer, including a micro nutrient mixture with iron on it.

I got the rock through a trade for a spare 10 gallon I had so its definitely worth it to try.

As for the sand, silicates are a highly debated topic iirc. I don't know if it has been finally researched enough yet. These pictures are a little bit older, the tank is now 26 days old (will update soon) but these photos are from day 4. Since then there has been a bloom in cyano and diatom algae. It's not super crazy but I chalked it up to new tank issues. But hey, that's what experiments are for. I don't plan to replace the sand any time soon.

 

[Devaji]

It's true that lava rocks are avoided due to the fear of iron leaching into the tank from them. However macroalgaes use iron for their growth, so I am not concerned by any leeching small or large.

Right now the nutrients are super high in the tank, but as the macro starts to consume them I will be dosing fertilizer, including a micro nutrient mixture with iron on it.

I got the rock through a trade for a spare 10 gallon I had so its definitely worth it to try.

As for the sand, silicates are a highly debated topic iirc. I don't know if it has been finally researched enough yet. These pictures are a little bit older, the tank is now 26 days old (will update soon) but these photos are from day 4. Since then there has been a bloom in cyano and diatom algae. It's not super crazy but I chalked it up to new tank issues. But hey, that's what experiments are for. I don't plan to replace the sand any time soon.

yeahI am a huge macro algae fan myself setting up a seahorse tank that will have quite a bit of them.

what ferts do you plan on using the powered stuff?
anyway keep us posted!

 

[AydenLincoln]

Let us know how it goes! I should warn you though not only will it leach unwanted chemicals into the water the wood will lower pH and may discolor the water significantly.

 

[Diastro]

Let us know how it goes! I should warn you though not only will it leach unwanted chemicals into the water the wood will lower pH and may discolor the water significantly.

No pH lowering here lol. The pH altering capacity of driftwood is over stated. I started the tank at 8.0 pH, last test showed 8.2 pH. But it is still young, more time will tell. In my freshwater tanks there is zero lowering after a two years though.

The water has a slight tint now. Only noticable when removing water. Driftwood was soaked in hot water to remove tannins before adding.

Can't wait to update!

 

[Diastro]

yeahI am a huge macro algae fan myself setting up a seahorse tank that will have quite a bit of them.

what ferts do you plan on using the powered stuff?
anyway keep us posted!

Ohh seahorses, that will be a beautiful tank.

My plan is to dose some freshwater ferts I mixed myself. Specifically pps pro dosing method from nilcoc g. https://nilocg.com/products/na-pps-pro-aquarium-plant-fertilizer-package

I bought these for my freshwater tanks but it makes a ton of fertilizer and seems to have everything needed for macroalgaes. This is also part of the eplxpirement.

 

[Gumbies R Us]

Excited to see where the tank goes from here!!

 

[Devaji]

Ohh seahorses, that will be a beautiful tank.

My plan is to dose some freshwater ferts I mixed myself. Specifically pps pro dosing method from nilcoc g. https://nilocg.com/products/na-pps-pro-aquarium-plant-fertilizer-package

I bought these for my freshwater tanks but it makes a ton of fertilizer and seems to have everything needed for macroalgaes. This is also part of the eplxpirement.

yes that is the stuff I was thinking about. almost set up a planted FW tank. was looking it to that.

careful someone will see it works for macros then make a liquid & bottle it and sale it at 100X the price. haha

 

[haigyfish]

yeahI am a huge macro algae fan myself setting up a seahorse tank that will have quite a bit of them.

what ferts do you plan on using the powered stuff?
anyway keep us posted!

Any thoughts on a dwarf seahorse tank?

 

[Tom.E]

Following along. Have you determined future stocking for the tank yet?

 

[Diastro]

Update: Day 27

Sorry for wonky pictures. The micro algae is out in full force. Diatoms and cyano cover the tank. I spent 20 minutes before this picture was taken just cutting and removing caulerpa that was full of cyano. Note to self, get a magnetic algae scrubber.

The caulerpa has grown a ton since then, it is infesting the area behind the rock. I had to remove a good chunk.

I've added new macros green dot algae and dragons tounge. The dragons tounge seems to have taken a beating in shipping, hopefully it pulls through.

Lots of friends have joined the tank, including bristle worms, stomatella snails, amphipods and copepods, Asterina starfish, a brittle star, and my favorite: Medusa worms. Actually a kind of sea cucumber and fun to watch.

I've been dosing brightwell microbacter daily hoping that it would outcompete the microalgae but I'm not sure it's done anything for the algae or the cycle.

I'm pretty sure I know the cause of the microalgae issues though.

1. I have a hygger plant light that has a default settings of coming on at 6:30 am and turning off at 6 pm. Then it has a "moonlight" mode of blue light that goes from 6 pm until 1130 pm. So yeah that probably helped the algae bloom. I changed the settings so it only has daylight for 8 hours and moonlight for 2.5. Hopefully that will combat the algae.

Next, the tank has a marina slim 15 gallon filter. The flow is so weak, I think it's contributing to the cyano issue. I definitely want to upgrade the filter to the seachem tidal 35, hoping that will be strong enough to properly circulate the tank.

If that fails, I do have some chemiclean on the way that I can use to hopefully rid myself of this ugly algae once and for all.

If anyone has any tips or advice I welcome it.

 

[Diastro]

Following along. Have you determined future stocking for the tank yet?

I was thinking a clown fish. It's only 8 gallons so stocking options are limited. I am open to suggestions though!

 

[Diastro]

Minor update Day 29:

Lights were off for the last two days due to me setting them incorrectly and I wasn't home to know it.

Nuisance algae definitely decreased, but the green dot algae definitely took a hit.

It's not looking good, hopefully it will recover from the poor lighting conditions. The dragons tounge is still surprisingly improving every day.

The tank has a bunch of tiny bugs along the walls, I assume they're baby amphipods since I've been seeing a bunch of adults scurrying as around. Hopefully the tank will stabilize soon so that I can purchase some more expensive macros without a fear of them dying and me wasting a bunch of money.

 

[Diastro]

Update Day 36:

I resorted to chemiclean. It had to be done. I dosed it twice before it did anything. But that disgusting cyano is finally gone.

Sadly, the green dot algae I was hoping would recover shriveled up and died. Luckily, a piece that had broken off before the disaster has survived and is already growing! It very small though so it will probably be a while before it grows big enough to replace the lost macroalgae chunk.

Magnetic scraper arrives tommorow, I hope to finally clean up the glass from the last of the diatom algae.

Copepod explosion in there, and amphipods. I love it though.

Since I've gotten the cyano algae under control, I've finally decided to bite the bullet and order a bunch of macros from a fellow hobbyist. I'm expecting them some time next week, lots of beautiful ones. I can't wait to get them!

 

[AtlantiCat]

Love this idea! I'm a freshwater plant keeper myself and I have a bunch of nano tanks. I've been considering converting a 5 gallon rimless to salt after the guppy fry have grown out of it. If yours works out, I might "steal" your experience and try my own.

 

[Diastro]

Minor update: Day 38

Algae scraper finally got put to use. Eh it's not super good but it definitely helped clean up the tank. Algae grows super fast, the green dot caulerpa that I have has dobled in. Size in just days.

Looks out of control lol. I wanted to share something very cool about this tank, the macroalgae glows!

Well at least the dragons tounge does. It looks super cool in the moonlight mode.

I'm hoping to add some beautiful but easy frags that will glow in the moonlight mode but can survive the daylight freshwater lights.

I'm also really interested in adding some gorgonians to the tank to add some beautiful color.

 

[Diastro]

Update Day 46:

So many exciting things! I finally stocked the tank! I have added a clownfish names Bemo. So far he loves snacking on the copepods, and he's eating pellets well. I'm thinking of adding some sexy shrimp to the tank to add some more life while not overcrowding the tank.

Next, the macroalgae I got has arrived!

I got some blue hypnea, codium, acid rain, gracilaria mammalaris, red pearl algae, and halimeda. Everything is looking good so far and adjusting. Besides the acid rain which still looks pretty beat up. It's been about 4 days. The halimeda is already growing super fast.

This photo doesn't do it justice, the blue hypnea is absolutely beautiful, but it looks pretty gray so far down in the tank. I plan to let it grow there and then move it up in the tank so the beautiful blue color shows up better.

Codium matching the driftwood.

Gracilaria mammalaris I believe.


The caulerpa on the rock is growing like mad. I added a mL of macro and micro nutrients when the new algae was added and it loved it. I had to trim back so much. I almost regret it.

 

[GirlWithFish]

Beautiful! I am also trying to make a macroalgae tank coming over from fresh to salt I see the light you are using, do you recommend that light or a traditional reef light? Do macroalgaes need plant lights or blue marine light? I’m not planning corals but I will have live rock so I’m not sure what light to buy

 

[Diastro]

Beautiful! I am also trying to make a macroalgae tank coming over from fresh to salt I see the light you are using, do you recommend that light or a traditional reef light? Do macroalgaes need plant lights or blue marine light? I’m not planning corals but I will have live rock so I’m not sure what light to buy

Highly recommend the light. Or really any freshwater planted tank light. Macroalgae are more like plants than corals.

Growth is great with this light. I also plan to add corals with this light, and see how that goes.