Re-thinking my goals

[HawkeyeDJ]

A little over a year and a half ago, I decided to get into the hobby. Space and money were considerations, so I picked an Aquatop 24g AIO cube.

I was patient. I made a few mistakes, but my vision was to have a beautiful tank with a variety of mixed corals and a handful of fish.

I thought I had adequately upgraded the included light, but I had not. I have fought algae ever since I introduced some live rock. I eventually added corals: zoas, hammers, montipora, frogspawn, blastomussa, pulsing zenia, green star polyp, and toadstool leather, 24k leptoseris, 4 color cyphastrea.

I can't turn the white light up without the algae going crazy (Orbit Marine IC PRO Dual LED Light Fixture - with LOOP Control) and the blues alone are not strong enough for most of the corals. Most of the corals did not grow, and the algae just killed the sps.

I knew that the small tank would be a challenge in keeping the parameters within acceptable, so I am faithful in my water changes. Right now I change 20% (5 gallons 2x month). My parameters are relatively stable. Occasionally my phosphates bottom out but not for long. I run GFO and carbon (ROX .08). I typically test once per week.

The only corals that are really growing are the toadstool (high in tank) and the GSP at the bottom.

I'm not inclined to invest in more expensive lighting at this point, or replacing the lost sps. The anxiety is too much. The lack of zoa growth is a huge disappointment, too.

So now I'm thinking I'm going to let the gsp take over. It's beautiful and I've seen some tanks that are gsp exclusive. I won't have to fret over every detail and the algae has no effect on the gsp. If I do this, I expect the algae to finally surrender. Then I can turn the lights up and enjoy the tank more.

Thoughts?

Here is the tank a few months ago.

 

[KQuillan]

Do you have a CUC? What are your parameters?

 

[Nano sapiens]

To my eye, the corals themselves actually look quite good. I suspect that the light intensity is just enough to stimulate good pigmentation in these medium to lower light corals, but not enough to stimulate growth. And quite likely your rocks are leaching PO4 as it becomes depleted via the GFO usage...and the algae are immediately sucking it up at the source. So basically, a system can be 'PO4 nutrient rich', just not in a way that's test kit measurable in the water column.

Curious, do you vacuum the substrate at all and blow off detritus regularly from the rocks?

Assuming your PO4 and NO3 are within reef acceptable norms, if I were you I'd make sure I had a good CUC in place and then start to very slowly add more white light. Keep an eye on your PO4 and NO3 (keep them as stable as you can) and if algae starts to visibly spread first remove as much as you can by hand (becomes a form of nutrient export for the tank and helps the CUC to keep up) and add additional CUC if necessary.

Vacuuming the top layer of the substrate with your WCs to remove detritus buildup can also be helpful (if you aren't doing this already). If you haven't done this at all, then you should do it in sections over time so as not to destabilize the system.

 

[HawkeyeDJ]

Do you have a CUC? What are your parameters?

CUC: 2 tiger conchs, 4 nassarius snails, 3 turbo snails, 5 trochus snails, 1 peppermint shrimp, 6 margarita snails.

Parameters:
temperature: 77.1-77.3 over past six months.
pH: 7.8-8.0 over past 18 months
Ammonia: 0 past 18 months
nitrite: 0 past 18 months
nitrate: 15ppm - 18ppm over past six months
phosphate: 0ppm - 0.05ppm over past six months
salinity: 1.024 -1.025 over past 18 months
Alkalinity: 11.2 - 11.9 over past 6 months
calcium: 440-460 over past 6 months
Magnesium: 1400 - 1490 over past 6 months

I use 4 inch filter socks changed @ 3-4 days

 

[HawkeyeDJ]

To my eye, the corals themselves actually look quite good. I suspect that the light intensity is just enough to stimulate good pigmentation in these medium to lower light corals, but not enough to stimulate growth. And quite likely your rocks are leaching PO4 as it becomes depleted via the GFO usage...and the algae are immediately sucking it up at the source. So basically, a system can be 'PO4 nutrient rich', just not in a way that's test kit measurable in the water column.

Curious, do you vacuum the substrate at all and blow off detritus regularly from the rocks?

Assuming your PO4 and NO3 are within reef acceptable norms, if I were you I'd make sure I had a good CUC in place and then start to very slowly add more white light. Keep an eye on your PO4 and NO3 (keep them as stable as you can) and if algae starts to visibly spread first remove as much as you can by hand (becomes a form of nutrient export for the tank and helps the CUC to keep up) and add additional CUC if necessary.

Vacuuming the top layer of the substrate with your WCs to remove detritus buildup can also be helpful (if you aren't doing this already). If you haven't done this at all, then you should do it in sections over time so as not to destabilize the system.

I should point out that about 9 months in, I decided to change my rockscape to what you see in the pic above.

I designed the scape outside the tank (dry rock) then I placed it in a 10 gallon tank, filled it with water from the 24g water changes, added a heater, ran a circulation pump and added a bag of GFO. Cycled it and ghost fed it weekly. Phosphates tested in this tank 0.0 for three months before I placed the scape in the 24g. there were no lights on this tank at all for 3 months.

I only had pulsing zenia and GSP before I swapped out old scape and added the new. All the other corals were added simultaneously once I was certain the parameters were stable.

So far I have lost the monti, the blasto, the 4 color cyphastrea, and the 24k lepto is almost gone. The toadstool has tripled in size, the gsp is thriving like crazy. Everything else is either stagnant or slowly shrinking.

 

[Nano sapiens]

I should point out that about 9 months in, I decided to change my rockscape to what you see in the pic above.

I designed the scape outside the tank (dry rock) then I placed it in a 10 gallon tank, filled it with water from the 24g water changes, added a heater, ran a circulation pump and added a bag of GFO. Cycled it and ghost fed it weekly. Phosphates tested in this tank 0.0 for three months before I placed the scape in the 24g. there were no lights on this tank at all for 3 months.

Ok, that explains a lot as your rocks did look a bit sterile and more like dense dry rock than typical live rock. Tanks set up with all dry rock will take a lot longer to mature biologically and be able to support all coral types. You can help the process by adding true live sand, live mud or a few pieces of live rock.

Your stated parameters are within reef keeping norms. Although higher Alk is known to promote coral growth, I have had better overall health results dropping alk down a bit (8-9 dKh) and keeping it very stable. Keep PO4 measurable (0.05 ppm is fine) and as stable as possible to avoid bottoming out.

An ICP test could help you determine if something we can't test for is not right and an Aquabiomics report can tell you the state of your microbiome and whether you have any known coral pathogens.