Can coralline algae survive with only natural light? Fish only tank (currently) with diatoms.

[BoomFoxx]

TL;DR What are the chances that I could toss some Coralline algae into this tank that only gets natural light and have it out-compete diatoms on my rock?


I've got diatoms, and I don't think they are going anywhere because of my setup. It is a new fish-only tank (2 months old), so this is to be expected. I'm looking for something that will out-compete the diatoms or will help lessen their spread while not adding a skimmer or reactor. Here is way too much information and some thoughts I've had plus some pictures below of the setup. I just did a water change and glass scrapping yesterday. I've only been in the saltwater tank hobby for about 6 months now, and I'm looking for suggestions or recommendations!

• I have been overfeeding lately, and I know this can cause diatom spikes. About a month ago, I noticed one clown had stringy white poo, which looked like signs of parasites. Since then, I have been feeding mysis with Focus and MetroPlex, but it doesn't appear to have been working, and now both clowns have it. This last week I stopped feeding mysis to see if that was a factor; apparently, sometimes mysis causes the white stringy poo. Not the case, so I dosed PraziPro today. Hoping to go back to normal (less) feeding once I know everyone is healthy again.
• I don't have much water movement in the tank at the moment since it's just the two clowns. I was thinking about adding a small pump to add flow. I've read that this can help stop algae from being able to settle.
• I've also contemplated adding a snail to my cleanup crew to see if it could munch on the diatoms on the rock and glass. The conch is amazing at keeping my sandbed turned and clean. (On the rare occasion that things are too clean, I have algae pellets for him to make sure he doesn't starve, but it hasn't been an issue since I got him.)
• Patience? Will just waiting it out really work? Without any filtration like a skimmer, I feel like I'm just always going to have some diatoms, and lets be real, it's ugly.
• I love the idea of getting some coralline algae to grow in this tank, especially if it will push out the diatoms. I read up on the needs of coralline algae, and I'm not 100% sure if it would grow in a tank with only natural light. I have an H80 Tuna Flora Refugium LED Kessil that I could use, but I don't really want to encourage anything else to grow. Maybe this wouldn't be a problem since I used dry rock? And if the diatoms are growing with just the natural light, then wouldn't that be a sign that it might be enough for Coralline? I haven't been able to find anything solid on this topic. Coralline algae also seems to be hit or miss with people. I think I would need to make sure the tank temp is between 78-80 for it.

Tank Info

• 10-gallon Waterbox setup 3/1/21
  • Dry rock (Reef Saver)
  • CaribSea Live Sand
  • Cobalt neo-therm heater
  • Kracken lid
  • No water movement except for the pump the tank came with
  • No lights, but it gets indirect sunlight (MN)
  • MarineLand Bio-filter ball media
  • MarinePure Sphere Bio-Filter Media
  • 2 filter sponges
• Fish & Inverts only
  • 2 Domino clownfish
  • 1 strawberry (fighting) conch
• Parameters
  • ~77.8 degrees F
  • 34 ppt salinity
  • 0.09 ppm phosphate
  • 7.87 pH (low, but both our tanks sit around here regardless of increased airflow from outside or additional flow)
• Maintenance schedule
  • New filter fleece weekly
  • Large water change (15-20%) every 1 & 1/2 weeks with light sand sifting, toothbrush scrubbing, and rinsing of filter sponges
  • Small water change (5%) every week
  • Tunze ATO - not currently working but should be up in the next week

 

[MnFish1]

1. Many people would suggest not dosing medication in the display tank (underdosing, etc) if its adsorbed onto the rock - and the problem estimating the correct tank volume (overdosing)
2. Something is going to grow on the rock unless you put something on it. I know some people with FOWLR periodically take out their rock and clean it - so it stays 'white'
3. You could try some 'purple up' (you can google it) - but its basically 'coralline algae' that you can use to seed your tank. Remember, coralline algae requires proper alkalinity, calcium, etc - so its almost like having a 'reef tank' as compared to a FOWLR.
4. I have direct sunlight on my tank as well from about 8AM to noon - with no diatoms (as well as a bright LED) - So I don't see any harm using the light.
5. Raising the pH may help. Some people use the marine buffers - which people don't recommend per se in 'reef' tanks - but are ok in FOWLR.
6. how often are you doing water changes, etc.

 

[BoomFoxx]

Thanks for the response!

I'm doing a 15-20% every 1 & 1/2 weeks with light sand sifting, toothbrush scrubbing, and rinsing of filter sponges, and small water change 5% every week.

I thought about setting up a quarantine to medicate but I didn't want to add to their stress. If the Prazi doesn't work or if I start turning this into more than a FOWLR I will definitely quarantine when I medicate.

I've seen the purple up and other coralline seed mixes from Algae Barn and whatnot. I guess trying it out wouldn't harm anything to see if it would work. I do have the ability to test calcium and whatnot, I just haven't bothered since it's FOWLR.

Q: Wouldn't cleaning rock, even in a FOWLR get rid of helpful bacteria that I've spent all this time allowing to settle in?

 

[MnFish1]

Thanks for the response!

I'm doing a 15-20% every 1 & 1/2 weeks with light sand sifting, toothbrush scrubbing, and rinsing of filter sponges, and small water change 5% every week.

I thought about setting up a quarantine to medicate but I didn't want to add to their stress. If the Prazi doesn't work or if I start turning this into more than a FOWLR I will definitely quarantine when I medicate.

I've seen the purple up and other coralline seed mixes from Algae Barn and whatnot. I guess trying it out wouldn't harm anything to see if it would work. I do have the ability to test calcium and whatnot, I just haven't bothered since it's FOWLR.

Q: Wouldn't cleaning rock, even in a FOWLR get rid of helpful bacteria that I've spent all this time allowing to settle in?

No - IMHO scrubbing the rock would not do that @brandon429

 

[brandon429]

Hey agreed I’ve never seen basic cleaning remove the filtration components from the rock, be they bacteria or other life forms. This is coming from eval on thousands of times we even burnt the cleaned rocks in peroxide lol. Set them back on rip cleaned sand, and it still didn’t recycle, even with emersed peroxide burn

whatever live rock filtration components are, they’re tough. We don’t even care if someone burns them with 35%, it’s still not sterilizing the entire surface, too porous and jagged in my opinion. What I havent tested was a one hour submersion in straight 35% lol we are up to that degree in order to find ways to undo a cycle.

 

[brandon429]

Just to show strength look where Amalee75 who was not kidding around, jetted her entire rock set with blasted tap water. And the sand

she broke skip cycle laws because she disliked algae, that permanent stuck with me. And in doing so, she shows yet another degree of tough a basic cycle will display. These weren’t even all that porous of rocks either, it still didn’t recycle:




just clean you rocks off with simple saltwater and a clean dry rag wet w saltwater it’s harmless. Rinse off, set clean rocks back and hand guide it until coralline takes over. This crazy cleaning examples shows you the range of options though
https://www.reef2reef.com/threads/amalee’s-75g-build.700029/page-5

 

[brandon429]

Coralline grabs on nicely, a rag cleaning won’t dislodge it. Perx would burn it for sure though.

 

[BoomFoxx]

Thank you both! I think I'll give Coralline a try!