My Penninsula 500

JonasRoman · Aug 22, 2025

Hi. here is my tank. Penninsula 500 l. kessil A360X. Sump with some Aquaforest biostone (most area). Floating scape with a lot of open undisturbed sand area. Deep 5 cm
PO4: 0.02
NO3: 0.8
Ca, Kh, Mg: Normal

No additions besides the Balling (At the moment triton 7)
WC sporadically, with red sea black bucket

Mostly sps, some lps, and quite much fish. All QT, have had no deaths or diseases in tank besides the very first introduction of one clown, and one centr. loriculus. No obvious reason of that death (no external signs).
The QT has been a combination of TT and Formaline.

/Jonas

JumboShrimp · Aug 22, 2025

Love it, love it, love it!

JonasRoman · Aug 22, 2025

some pics aswell

JonasRoman · Sep 14, 2025

Follow up. Tank is going well. Started to try to dose F based on ICP, and since then alk consumption increased. I cant see any obvious diff in tank health, but at least not any bad signs since I started to dose. I will only dose based on ICP, as its very bad to overdose this (as for many other traces).

PO4 is a little higher now thanks to more feeding with frozen food. Circles around 0.06 mg/l. Nitrate 2-3 mg/l.

Post a pic from a favorite one, Pavona Maldiviensis. Slow starter, but now finally start to growth.

JonasRoman · Sep 20, 2025

An update. The tank is going well, actually my PO4 levels raised suddenly from 0.02-0.1 due to a fish that was dead. A Midas that jumped out, I catched and put it back, but it diesd a few days later due to irreversible injuries. Interesting to see how small changes give immediately changes in PO4.

The fishes is:
Centropyge bispinosus
Pom. Imperator
Apolomectus xanctopunctatus
Acant leucosternon
Naso Lituratus
amph ocellaris (3)
Midas (1)
Anthias squampini (6)
Euxiphipos navarchus

Mixed reef

Some pics and videos from today

Nutrients:
NO3 approx 2-3 mg/l
PO4: 0.02 (but now a few days 0.1)

Light: kessil 360X. (3)
Volume 500l. Peninsula

Scape: Non natural , "Coraroc". Large sandbed/area due to floating scape. Deep 5 cm, grain size small to medium. Some animals in sand like sanddollar, sea stars, eremites.

Besides Balling (at the moment triton ), addition of Fluor, Iodine and Manganese based on ICP lab. No other additives.

Water change sporadically, Red Sea black

9 kg live rock in sump, and AF biostones, and 2 maxspect anaerobic bioblocks.

The video please look at 4K (recorded in that)

/Jonas

JonasRoman · Sep 22, 2025

Coral garden

JonasRoman · Oct 11, 2025

today. Its growing now

JonasRoman · Jan 17, 2026

Hi my friends. Long time since updated this thread. Tank is going very well and corals growing. I use a sort of unnatural "stone" named Coraroc. A swedish invention. Finally the material is overgrown with calcareous algue and looks fine.
The stone waa consuming po4 quite long time buy not its saturated I believe. Despite heavy loaded tank now with 23 fishes, Nitrate is only 3 ppm. I guess thanks to my open sandbed and maybe also maxspect anareobic block, a few in sump. Po4 was low for a year but not as stone are saturated its climbing according to what I introduce, but stable now around 0.08-0.1 ppm.

Just some pic from yesterday.

JonasRoman · Jan 17, 2026

A short video aswell

JonasRoman · Jan 17, 2026

Try a video

JonasRoman · Jan 17, 2026

JonasRoman · 2026-07-14T04:16:32-0400

Update. Its very stable since 18 months back. White sand, NO3 2 ppm, Po4 0.03. No addition of any kind, just ordinary 3 part dosing. No living rock (just a few kg in the sump, probbaly of no importance now). Actually only the sand bed is the biofilter here.

Why is my tank so stable, and nutrients well balanced? I have a huge load now with 20 fishes, som large. My theory is in a YT on my site but I will summarize here:

AMO its the open sand bed that explains this. I got this idea when I was in Egyptian and observed these enormous area of open sand, and not much rock. In a tank when you place a stone on the sand, the sand beneath will be not so biological active. So the key is (AMO)
1) to have large open free sand areas. So i decided to arrange an floating scape, so all my bottom with sand is 90% uncovered, meaning allt his area is biolgoical healthy.
2)The deep is 5 cm, thats sufficient for denitrifiaction.
3) I have no fish that can disturb the sand=destroy anaerobiz zoones.
4) Invertebrates in the sand like sand stars, sand dollars etc
5) Fine sand, not too coarse. Thansk to small grain size the organic will sediment more slowly through the sand, so bacterial activity will have time to digest it, and make different zoones in the sand bed.

pics and video below