n=1 | Quick Barebottom Cycle for SPS | AKA the DENADAI Method | For Fun/Tracking Only

[naterealbig]

Idea: Set up system with the ability to add SPS to a new aquarium almost immediately, starting with uncured dry rock.

Pillars: (in order of importance (and, just what I believe)):

1. Zero fish load for first several weeks. Relatively large amounts of ammonia and fish food in immature aquaria feeds algaes and promotes pest algae proliferation. Additionally, it will encourage the opportunistic bacteria, disproportionate to that which you would find in a mature, healthy reef.

2. Seeding tank with live sand (either from mature aquarium or directly from ocean).

3. Immediate (day 1) establishment of baseline PO4 level. Weekly testing and adjustments (up or down). Target 0.03 - 0.1 ppm PO4. PO4 is a requirement for algae (and coral) growth, and is the very beginning of the food chain within aquaria. PO4 feeds algaes (and helps keep dinoflagellates at bay) > feeds copepods, snails, and various other members of cleanup crew.

4. Daily (starting day 1) Alkalinity testing & adjustments. High alkalinity consumption observed during initial biome cycling. Standard alkalinity levels required for optimal health of cleanup crew, and of course, the corals.

4b. I utilize All For Reef (Tropic Marin Product) which supplies Alkalinity, calcium, magnesium, along with trace elements in a single solution. If you are using a two, three, or whatever-part product you will need to maintain calcium and alkalinity levels as well. Alkalinity is by far the most important component of the 'big 3'.

5. Cleanup crew addition (week 1):
Copepods: Benthic. Can reproduce to carrying capacity, and feed on algae films, diatoms, and potentially dinoflagellates.
Blue leg hermits: Excellent algae eaters. My observation is that they clean the rocks better than any snails.
Snails: Help keep glass and rock free of algae. I utilize Trochus, which reproduce in the aquarium eliminating the need for replenishment. Snails will introduce various algaes (notably Coralline) into the system.
Micro Serpent Stars (optional): Eat detritus. Can get into the smallest holes/crevices that the crabs and snails cannot get to.
Bristle Worms (optional): Same as Micro Serpent Stars
** Important note: wait until aquarium begins growing algae before adding copepods and snails, otherwise they will have no food source.

Additional Pillar/Lessons Learned:

UV Sterilizer:
Can prevent/remedy algal/bacterial blooms in the water column which can quickly absorb PO4. Adding a UV Sterilizer can potentially stabilize PO4 levels and reduce/eliminate additional PO4 adjustments during cycle.

 

[naterealbig]

Photo Log:

SPS

Day 5 (12/28/25):

Day 10 (1/2/25):


FTS

Day 5 (12/28/25):

Day 10 (1/2/25):


Sump/Equipment


Random Photos

 

[naterealbig]

Written Details/Log:

Day 1:
1) Fill tank with water mixed to 1.026 specific gravity. I used Tropic Marin Pro.
2) Install and place into service, all equipment. For this setup, an appropriately-sized protein Skimmer (Tunze), Carbon (~ 1 cup, BRS ROX), Filter Sock (~ 200 micron), Ranco-controlled heating element. Lighting & Flow (Ecotech, Tunze, respectively)
3) Add dry rock. For this setup, ~ 0.3 lb per gallon (150 gallons total, 35 lb rock, approximate)
4) Add live sand. For this setup, ~ 0.05 lb per gallon (~ 7.5 lbs sand, approximate) placed in the sump in an open, plastic container. Sand was purchased from gulfliverock.com. I purchased 15 lb, shipped overnight. Sand + shipping was $95. Sand had many different size grains, and to my delight, a lot of shells and stuff with coraline.
5) Sprinkled ~ 1 cup of the live sand onto the dry rock in the display.
5) Test Alkalinity (reading 8.3 dkH per Hanna)
6) Leave lighting on 100%, 24 hours a day to encourage initial algae growth.

Day 2:
1) Test PO4. (reading was 0.08 ppm PO4 per Hanna ULR). Within desired range, no adjustment needed (however, have both lanthanum chloride & trisodium phosphate handy, for down & up adjustments, respectively).
2) Test Alk. (reading 8.1 dkH per Hanna). Set initial dose of 5 ml A4R, daily.

Day 3:
1) Observed slight cloudiness in water, likely bacterial/algae bloom. Ordered 40W UV sterilizer to place on line temporarily to remove cloudiness.

Day 4:
1) Observed diatom growth on rock. Still running lighting at full power 24/7 up to this point. Adjusted lighting to normal photoperiod.
2) Continue daily alkalinity testing, adjusting dose as necessary to maintain 8.0 - 9.0 dkH.
3) Added ~ 30 small Blue Leg Hermits ( about 1 crab for every 5 system gallons - 30 crabs total)
4) Added ~ 30 Trochus snails ( about 1 snail for every 5 system gallons - 30 snails total).

Day 5:
1) Tested PO4 (reading 0.08 per Hanna ULR)
2) Added corals: 16 ea Acropora specimens, 4 Montipora specimens, 1 soft coral specimen, and 1 ea Entacmaea quadricolor (RBTA). 2 of the Monti and 4 or so of the Acro specimens are duplicates.
3) Added 20ml DIY Amino Acids

Day 6:
1) Tested PO4 (reading 0.00 per Hanna ULR). Interesting. Considering the idea that with amino dosing, waste from cleanup crew, increase in nitrate caused decrease in PO4. I would test to NO3, but I don't believe it is super important at this moment. Dosed PO4 (trisodium phosphate) that should increase PO4 from 0.00 to 0.10 (not 0.01), and will retest tomorrow.
2) Dosed 15 ml DIY Aminos & 2 cubes of DIY coral food to hopefully provide some nourishment to the cleanup crew.
3) Inspected corals and there does not appear to be any tissue necrosis. All members of cleanup crew still alive.

Day 7:
1) Tested PO4 (reading 0.00 per Hanna ULR). This is despite dosing enough Sodium nitrate to raise PO4 level to 0.1 ppm. It just occurred to me that it is the algae/bacteria (I'm leaning towards algae) consuming the PO4. Interestingly, I have observed Dinos start to show up @ 0.00 PO4 levels. However I also recall that when the dinos show up that the water is clear (without bloom). One reason may be that there is enough dieoff/growth of the algae/bacteria that the phosphorus is available in such a manner that keeps the Dinos at bay. I have no idea on the mechanism (but speak up, I'm willing to learn!).
1a) I'm anticipating that once I bring the UV sterilizer online that PO4 will step increase to ~ 0.10 - 0.15 ppm, which will need to be handled quickly with Lanthanum Chloride.
2) Alk tested 8.5 dkH per Hanna, and I'm settling on a daily dose of 5 ml of A4R.
3) Observation of corals is positive. Polyps on most frags are extended, and do not seem to have lost any color. Yellow Fiji leather is ticked. No coral deaths to date. Lights are off at the moment so will need to double check, but I think I recall seeing a snail (Trochus) died. This could be attributed to some rough handling and H2O2 washdown while trying to prevent Bubble Algae intro into the display immediately prior to addition.
4) Dosed 20 ml DIY aminos to aquarium.
5) 55 w Lifeguard Sterilizer should be coming by Jan 2, however, I'm going to try running a smaller unit (with a couple-year-old bulb) first, to minimize equipment costs when it comes to replicating the test in the future.

Day 10: 1/1/2025
1) Important Notes: out of town vacation from Dec 29 - Jan 1. Set alkalinty dose to 5.0 ml; PO4 dose equivalent to 0.01 ppm daily, fed DIY coral food (DIY aminos, Reef Chili, Reef Roids) daily.
2) Observations: upon return, algae (will assume algae from here out) bloom had subsided almost 100%, and a light green film has formed over most smooth surfaces of the display. All members of cleanup crew are alive, and notably, rocks appear very clean while majority of hermits are attached and seem to be picking at it. All corals are alive and relatively colorful. Per my memory/eyes, SPS seem to have better color than day 5. Yellow Fiji leather continues to appear very unhappy, seems more brown and smaller since transfer, and is exhibiting no polyp extension.
(2a) If leather coral continues to appear to decline, some or all of the coral will be transferred to a known, healthy aquarium currently supporting Acropora sp..
3) Parameters: Alk = 8.8 dkH (Hanna), PO4 = 0.03 (Hanna). Will continue with 5.0 ml dose of A4R.

 

[jkrohn]

What size tank are you doing this on? I'm going to start a new tank up in February and was thinking about a similar approach so interested to see how this goes!

 

[naterealbig]

What size tank are you doing this on? I'm going to start a new tank up in February and was thinking about a similar approach so interested to see how this goes!

Tank is a 120g but custom dimensions: 58x24x20h. 40B sump. Approximately 140g total system volume. In the log, I am converting the stuff I'm adding to the tank to "per gallon" so theoretically, it could be converted to any size system.

 

[KrisReef]

I don't recognize the lighting being used?

Are some of your dry rocks from previous reef tanks or is it all recently quarried, or a mixture?

GL! Nice tank so far.

 

[naterealbig]

I don't recognize the lighting being used?

Ecotech Radion Pro XR30 G6s

Are some of your dry rocks from previous reef tanks or is it all recently quarried, or a mixture?

3 of the pieces were pulled out of my dry rock stash on day 1. The two largest pieces finished up a bleach and acid bath on day -1. Entire aquarium and system also received a bleach and acid bath on day -1.

So, the only media in the system that has established (or any) bacterial colonies is the tub of sand in the sump.

GL! Nice tank so far.

Thank you for the nice words!

 

[naterealbig]

Day 7:
1) Tested PO4 (reading 0.00 per Hanna ULR). This is despite dosing enough Trisodium Phosphate to raise PO4 level to 0.1 ppm. It just occurred to me that it is the algae/bacteria (I'm leaning towards algae) consuming the PO4. Interestingly, I have observed Dinos start to show up @ 0.00 PO4 levels. However I also recall that when the dinos show up that the water is clear (without bloom). One reason may be that there is enough dieoff/growth of the algae/bacteria that the phosphorus is available in such a manner that keeps the Dinos at bay. I have no idea on the mechanism (but speak up, I'm willing to learn!).

I'm anticipating that once I bring the UV sterilizer online that PO4 will step increase to ~ 0.10 - 0.15 ppm, which will need to be handled quickly with Lanthanum Chloride.

2) Alk tested 8.5 dkH per Hanna, and I'm settling on a daily dose of 5 ml of A4R.

3) Observation of corals is positive. Polyps on most frags are extended, and do not seem to have lost any color.
Yellow Fiji leather is ticked. No coral deaths to date. Lights are off at the moment so will need to double check, but I think I recall seeing a snail (Trochus) died. This could be attributed to some rough handling and H2O2 washdown while trying to prevent Bubble Algae intro into the display.

4) Dosed 20 ml DIY aminos to aquarium.

5) 55 w Lifeguard Sterilizer should be coming by Jan 2, however, I'm going to try running a smaller unit (with a couple-year-old bulb) first, to minimize equipment costs when it comes to replicating the test in the future.

6) *Unrelated* Regal Angelfish ordered; approximately 2 weeks away. Will be the first fish in the display (and likely the only for several weeks). Not that it matters, but plan on adding a harem of P. dispar (5 total) along with 15-20 C. viridis. Debating a few tangs (likely 3 Z. flavacens, and some from the Bristle Tooth family), however, if the hermits and snails can keep the rock clean enough I'll forego them. I'm aiming for a very 'artistic' reef rendition for this setup.

 

[sixty_reefer]

Day 7:
1) Tested PO4 (reading 0.00 per Hanna ULR). This is despite dosing enough Sodium nitrate to raise PO4 level to 0.1 ppm.

Was this a typo error? Sodium nitrate doesn’t raise phosphate.

 

[naterealbig]

Was this a typo error? Sodium nitrate doesn’t raise phosphate.

Sure was - should have written Trisodium Phosphate! Stayed up way too late tonight. Thanks.

 

[sixty_reefer]

Sure was - should have written Trisodium Phosphate! Stayed up way too late tonight. Thanks.

I’ve done a similar testing to yours in dark environments and I was surprised on how much phosphate was required initially for microbes to colonise the tank on my 15 gallon it required over 1ppm of phosphate in that first week. My suggestion would be to not starve them from phosphate in this early stage, you also may see less algae that way as it creates a competitive environment for surfaces.
I’ve aimed for 0.4 and doses as necessary till I’ve seen a slow down in consumption.

 

[naterealbig]

I’ve done a similar testing to yours in dark environments and I was surprised on how much phosphate was required initially for microbes to colonise the tank on my 15 gallon it required over 1ppm of phosphate in that first week.

That is a lot! Coincidently, I set up a 40B system using similar methodology about 4 weeks ago (these 'tests' are tied together - due to an Aiptasia infestation I allowed to get completely out of hand, I needed to remove corals from the display but couldn't use the live rock from it. I started with a mix of dry sand & Ocean Direct bagged live sand along with some dry rock. LPS & Polyps went into this tank (smh I'm still killing baby Aiptasia popping up in between Zoa/Paly polyps!). I saw the exact same thing you observed in your 15 g. I believe I dosed enough Na3PO4 to increase PO4 by ~ 0.04 ppm daily for almost two weeks straight. This was after observing a severe Dino outbreak within a couple days of setup.

I came to a completely different (and probably wrong, lol) conclusion in this instance. I attributed the 0.0 PO4 levels to absorption from the dry rock and sand.

On this tank (the one in this thread), I observed a steady (within target) PO4 level for the first couple days (i attributed this to less surface area to absorb phosphate (no substrate in display)), and saw (what i thought to be a correlated) drop in phosphate + algae/bacteria bloom in the water column. It made sense in my little brain, and I didn't even occur to me it could the establishing microbiome consuming the phosphate.

The conundrum I'm in at the moment, is I'm leaving for vacation, and need to leave pre measured supplements for the tank while I'm gone for 4 days.

How much should i leave to dose daily that would provide the minimum po4 needed but keep me away from a dose that would exacerbate the bloom and/or put corals at risk? (They seem very happy at the moment).. i would greatly appreciate your thoughts/recommendations on this.

My suggestion would be to not starve them from phosphate in this early stage

you also may see less algae that way as it creates a competitive environment for surfaces.

I’ve aimed for 0.4 and doses as necessary till I’ve seen a slow down in consumption.

All well received - thank you so much for your insight and recommendations. Please let me know your thoughts on my question above, re: PO4 dosing while I'm out of town (until jan 1).

Thank you!

 

[sixty_reefer]

That is a lot! Coincidently, I set up a 40B system using similar methodology about 4 weeks ago (these 'tests' are tied together - due to an Aiptasia infestation I allowed to get completely out of hand, I needed to remove corals from the display but couldn't use the live rock from it. I started with a mix of dry sand & Ocean Direct bagged live sand along with some dry rock. LPS & Polyps went into this tank (smh I'm still killing baby Aiptasia popping up in between Zoa/Paly polyps!). I saw the exact same thing you observed in your 15 g. I believe I dosed enough Na3PO4 to increase PO4 by ~ 0.04 ppm daily for almost two weeks straight. This was after observing a severe Dino outbreak within a couple days of setup.

I came to a completely different (and probably wrong, lol) conclusion in this instance. I attributed the 0.0 PO4 levels to absorption from the dry rock and sand.

On this tank (the one in this thread), I observed a steady (within target) PO4 level for the first couple days (i attributed this to less surface area to absorb phosphate (no substrate in display)), and saw (what i thought to be a correlated) drop in phosphate + algae/bacteria bloom in the water column. It made sense in my little brain, and I didn't even occur to me it could the establishing microbiome consuming the phosphate.

The conundrum I'm in at the moment, is I'm leaving for vacation, and need to leave pre measured supplements for the tank while I'm gone for 4 days.

How much should i leave to dose daily that would provide the minimum po4 needed but keep me away from a dose that would exacerbate the bloom and/or put corals at risk? (They seem very happy at the moment).. i would greatly appreciate your thoughts/recommendations on this.





All well received - thank you so much for your insight and recommendations. Please let me know your thoughts on my question above, re: PO4 dosing while I'm out of town (until jan 1).

Thank you!

In my experiment I’ve only used ceramic media as I wanted to evaluate the biological requirements of nutrients in a new set up. In your scenario rock will also be contributing for the absorption of phosphates imo.

The only suggestion I can give you is to try and calculate your daily consumption of phosphates for each 24h and dose accordingly to the period of time you plan on staying away from the tank.

 

[naterealbig]

In my experiment I’ve only used ceramic media as I wanted to evaluate the biological requirements of nutrients in a new set up.

Ah, excellent - completely eliminating calcium carbonate absorption of PO4 as a variable.

In your scenario rock will also be contributing for the absorption of phosphates imo.

Another helpful tidbit (it's not one or the other in my case; all things combined).

The only suggestion I can give you is to try and calculate your daily consumption of phosphates for each 24h and dose accordingly to the period of time you plan on staying away from the tank.

Makes sense, but at each dose of Na3PO4, PO4 has dropped to 0.0. If there was measurable PO4 at each (or any of the) test(s) I could put together a reasonable guess, but unfortunately there has not been.

I'll probably put together a daily dose that would increase PO4 by ~ 0.05. Assuming PO4 equilibrium is reached (bacteria & media) immediately and PO4 consumption completely stops, I'm only at 0.2 ppm the day I come back. I absorption continues, the PO4 dose likely won't be sufficient, but perhaps it will be enough to prevent the bacterial colonization from stopping completely.

You have been a great help, and thank you for taking the time to walk me through your thoughts.

Do you happen to have a thread on your testing/experiment you mentioned above? I'd love to take a read...

Best regards, and happy new year!

 

[naterealbig]

Day 10: 1/1/2025

1) Important Notes: out of town vacation from Dec 29 - Jan 1. Set alkalinty dose to 5.0 ml; PO4 dose equivalent to 0.01 ppm daily, fed DIY coral food (DIY aminos, Reef Chili, Reef Roids) daily.
2) Observations: upon return, algae (will assume algae from here out) bloom had subsided almost 100%, and a light green film has formed over most smooth surfaces of the display. All members of cleanup crew are alive, and notably, rocks appear very clean while majority of hermits are attached and seem to be picking at it. All corals are alive and colorful, and no necrosis noted with the exception of (what I believe to be) A. humilis in which 1 of the 2 fragments is showing a small area on necrosis. Yellow Fiji leather continues to appear very unhappy, seems more brown and smaller since transfer, and is exhibiting no polyp extension.
(2a) If leather coral continues to appear to decline, some or all of the coral will be transferred to a known, healthy aquarium currently supporting Acropora sp..
3) Parameters: Alk = 8.8 dkH (Hanna), PO4 = 0.03 (Hanna). Will continue with 5.0 ml dose of A4R.
5) Pics:
(before cleaning)

(after cleaning)

 

[naterealbig]

Day 11: 1/2/2025
1) Important Notes: Added 10k ea Copepods (benthic) from Reef by Steele (excellent experiences accross the board).
2) Observations: No return of algal bloom noted. Comparing day 5 and day 10 pics, coloration seems to have improved slightly on most fragments. Polyps still extended on all corals. CSB nem looks happy/healthy.
3) Parameters: Alk = 8.5 dkH (Hanna), PO4 = 0.02 (Hanna). Will continue with 5.0 ml dose of A4R. Stopping PO4 dosing as long as green algae 'dusting' continues to appear on glass.
4) Other Notes: Performed 20 g water change using TM Pro Reef. Unlikely that I will bring new 55W UV sterilizer online, as algae bloom has subsided. Day ~ 7 I anticipated that additional PO4 dosing would increase density of algae bloom (and continued 0.0 PO4 readings), but continued dosing while on vacation (equivalent to 0.1 ppm PO4 daily) per @sixty_reefer 's recommendation. This did not occur; in fact, the opposite happened - bloom went away, and PO4 levels rose slightly. Thank you so much for your help @sixty_reefer!!

 

[DenverSaltyFarm]

tank looks great! I started a 120gallon bare bottom and it was a hard 1st year then the tank was great! I now have a 200 gallon and the lessons I learned from the 120 made the 200 gallon go much better. I found out that the marco dry rock was soaking up my phosphates and it quickly turned to dinos. with your reading of .02 on your Hanna tester could actually be zero based on the error of the tester. I would highly suggest getting that number higher like around .07 and out of that danger zone for dinos to pop up. algae is much easier to deal with vs dinos. the nice thing with dosing phosphate solution to your water is you can test the tank 10 min after dosing to see where you have raised it to then see how much it drops in a 24hr period to get a good daily dose schedule for your tank. my tank was using up .05 PO4 daily. There is a point at which the rock will no longer soak up phosphate and you have to catch that transition so you know when to stop. Took me about 3 months of daily dosing to finally get the numbers to stay where I wanted them. Following along

 

[naterealbig]

tank looks great!

Thank you!

I started a 120gallon bare bottom and it was a hard 1st year then the tank was great!

Yes, the BB are blessings + curses all rolled into one!

I found out that the marco dry rock was soaking up my phosphates and it quickly turned to dinos.

I observe this as well; along with all other calcareous media...

with your reading of .02 on your Hanna tester could actually be zero based on the error of the tester.

I am aware of this pitfall... ask me how I know!!

I would highly suggest getting that number higher like around .07 and out of that danger zone for dinos to pop up. algae is much easier to deal with vs dinos.

Agreed - I'm content with ~ 0.03 ppm (along with the normal 'dusting' of diatoms, etc, understanding that the daily dosing will catch a dip below (reading of 0.02 ppm is my setpoint to take action, in the form of Trisodium Phosphate additions).

the nice thing with dosing phosphate solution to your water is you can test the tank 10 min after dosing to see where you have raised it to then see how much it drops in a 24hr period to get a good daily dose schedule for your tank.

Ah - learned something new! Thank you!

my tank was using up .05 PO4 daily.

Good god man!

There is a point at which the rock will no longer soak up phosphate and you have to catch that transition so you know when to stop. Took me about 3 months of daily dosing to finally get the numbers to stay where I wanted them.

Will keep this in mind, and, continue to test daily and dose for any reading below 0.03/4...

Following along

Great to have you here friend, and thank you so much for your pro-tips and insights.

Be chatting.

 

[naterealbig]

Hi @sixty_reefer - I tested nitrates today (corals are showing growth and color improvement, and CUC seems good. My Fiji Yellow Leather still looks super-angry) with Hanna High-Range photometer. Reading was 0.0.

Any concern here with nitrate limiting/slowing the bacterial maturity I'm working on establishing quickly in this system? If so, I suppose it would be worth getting my hands on a low-range NO3 checker. Also, at what level (or ratio (N : P) should I take action?

If nitrate dosing is recommended, what ratio should I use when dosing PO4 + NO3. If I were to take a swing, I'd probably start off with 100:1 (N : P) to make sure I don't bottom out PO4. Or should I be closer to (16:1)?

Any other key parameters I should be testing for and adjusting?

I'd be grateful if you shared your thoughts.



Thank you!

 

[sixty_reefer]

Hi @sixty_reefer - I tested nitrates today (corals are showing growth and color improvement, and CUC seems good. My Fiji Yellow Leather still looks super-angry) with Hanna High-Range photometer. Reading was 0.0.

Any concern here with nitrate limiting/slowing the bacterial maturity I'm working on establishing quickly in this system? If so, I suppose it would be worth getting my hands on a low-range NO3 checker. Also, at what level (or ratio (N : P) should I take action?

If nitrate dosing is recommended, what ratio should I use when dosing PO4 + NO3. If I were to take a swing, I'd probably start off with 100:1 (N : P) to make sure I don't bottom out PO4. Or should I be closer to (16:1)?

Any other key parameters I should be testing for and adjusting?

I'd be grateful if you shared your thoughts.



Thank you!

Hi, in my opinion it is necessary to take action. There isn’t a ratio that is more favourable regarding the residual nitrate and phosphate but it is essential for both to be detectable at all times, my advice is usually to keep them both at a minimum of your test kits, never lower.
There is some organism in our systems that require their presence and it will be a good safety in case of your other forms of nitrogen become limited.