Glass Reef

A 220 litre mixed reef in a Brisbane spare room, written down as it happens.

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About this site

Standing page · last edited 12 June 2026

My name is Dale Prentice. I'm a draughtsman, I live in Brisbane, and in the winter of 2019 I walked into an aquarium shop in Woolloongabba to buy a birthday present for my nephew and walked out having ordered a tank for myself. That's the entire origin story.

Glass Reef started in 2019 as a text file on my desktop, because I kept having the same conversation with myself about whether a thing had worked. It became a site in 2021 when a fellow in the local club asked if I'd write my cycling numbers down somewhere he could point people at. Everything here is the same notebook, just typed up.

What I'm not

I'm not a marine biologist, an aquaculture professional, or anyone with formal training in any of this. I have kept one display tank and one frag tank for five years now and I read a great deal more about this than I write. When I state something as fact on this site it's because I measured it in my own tank; when I'm guessing I try to say so in the sentence.

I don't sell anything. There are no affiliate links, no sponsored posts, no discount codes, and nobody has ever sent me a product to review. If I name a shop or a brand it's because I bought the thing with my own money and have an opinion about it. The site costs me about forty dollars a year, which is cheap enough that I can go on saying honestly that a skimmer was rubbish when it was rubbish.

The one thing I ask

If something here saves you a fish, don't thank me — go and answer somebody else's beginner question patiently. Every useful thing I know came from somebody in a club hall or a forum who could have been dismissive and wasn't.


The tank, in full

The gear list gets asked about often enough that it may as well have a permanent home, so here it is. Nothing in it is exotic and most of it has been chugging along for five years.

Display system as it stands in June 2026.
ItemWhat I runComment
Display220 litres, 120 × 45 × 45 cm, rimlessBraced with a plywood platform on the cabinet top. Check your floor loading before you buy glass.
Sump65 litres, three chamberSkimmer section, refugium with chaeto, return. The refugium earns its space.
Return pumpDC, around 1500 litres an hour at headOn its lowest useful setting. The controller died once in 2023 and was replaced under warranty.
FlowTwo small gyre style pumps, opposite endsAlternating, never both at full. Dead spots behind the rock are where detritus piles up.
LightingTwo LED units, ten hours with a two hour ramp each sideRamped up over three months when they were new. Going straight to full intensity is how people bleach a tank.
SkimmerCone, rated well above this volumeOversized on purpose. Took six weeks to settle down when new, which is normal.
Heater200 W plus a separate controllerThe controller is the important half. A stuck heater is the fastest way to cook a tank.
Top-offFloat switch and a 20 litre reservoirBuilt myself. The whole story is in the top-off post.
DosingTwo head peristaltic, alkalinity and calciumTube replaced every six months now, for reasons the alkalinity post explains at length.
WaterRO in 25 litre drums from a shop in MoorookaI don't own an RO unit. For 300 litres a month it isn't worth the plumbing.

Targets I actually hold to: salinity 1.025, temperature 26 °C, alkalinity 8.3 dKH, calcium 430 ppm, magnesium 1350 ppm, nitrate 5–15 ppm, phosphate 0.03–0.08 ppm.

Stability matters more than any of those numbers. A tank held steadily at 7.8 dKH will do better than one bounced between 7.5 and 9 every week.

The routine

Call it forty minutes a week all up. People reckon a reef tank is a daily chore and mostly it is not, once the gear that ought to be automatic finally is.


Get in touch

Everything that reaches me gets read, and the great bulk of it gets a reply inside a week or two, although that stretches out to something embarrassing whenever work goes mad. If I have gone quiet on you for a month it is because the thread has slid off the bottom of my inbox, so give me a nudge — that is welcome rather than rude, and honestly about half my replies only happen because somebody chased me up.

Three things that will get you a far better answer out of me:

  1. Tell me your numbers. Volume, how long it's been running, salinity, temperature, alkalinity, nitrate, phosphate. "My coral looks sad" with no numbers is unanswerable by anybody.
  2. Tell me what changed. Nine problems in ten start with something new — a new light, a new additive, a new fish, a water change with different salt.
  3. If it's an emergency, ask a shop or your local club, not a blog. I might not see your message for days, and a tank that's crashing can't wait for me.

Send me a note

Skip it if you are not after a reply — heaps of people fire off a correction and then vanish, which suits me fine.

Fair warning before you fill that in: the button does nothing at all just now. The little script that used to carry these notes to my inbox went west when I shifted hosts back in March, and I have not got round to replacing it, so the whole box is furniture until I do. The slower ways underneath are the ones that actually reach me.

The slower ways

I turn up at the local marine aquarium club meeting most months and I am generally the bloke down the back with the notebook open. If you are in Brisbane and asking out loud suits you better than typing, that is far and away the best way to get hold of me, and you will collect four other opinions for free, at least two of which will flatly contradict mine.

If you'd like to send something on paper, and one or two people a year do, there's a PO box in Annerley; ask at a meeting and somebody will have it written down.

Photographs and reposting

Every photograph and every word here is mine, shot or typed in a spare room in Brisbane. Quote a paragraph with a link back and you need nothing from me at all. Clubs and newsletters after a whole post: grab me at a meeting and I will almost certainly say yes, since I have not said no yet. The one thing I would ask you not to do is shovel the lot through a machine that spits it out again with my stuff-ups repackaged as confident advice, because the stuff-ups are load bearing and pulling the context off them turns a useful post into a dangerous one.

Privacy, such as it is

There are no cookies here, nothing counting visitors, and not one file pulled off somebody else's server — it is six hand-typed pages and a stylesheet sitting on a small host, and that is the lot of it. So I genuinely have no idea how many people read this, which bothered me for about a week in 2021 and has not since. If you post me an email address I use it to write back to you and for nothing else at all, it goes on no list anywhere, and I bin the thread once we are finished.


New here? Start with the cycling log. Curious what's swimming around? That's the livestock notes. Everything else is on the front page.

Glass Reef — a hobby diary typed up in a spare room in Brisbane, Queensland. Nobody sponsors it, there are no affiliate links anywhere in it, and there is nothing on it for sale.

Copyright © 2019–2026 Dale Prentice. Back to the front page.

I last had a fiddle with this page on 12 June 2026, when the gear table got updated after the return pump swap.