Kalkwasser has a lot going for it.

It provides a stronger pH boost than most two-part systems, doesn't increase salinity with sodium chloride buildup, may help precipitate phosphate, and is dramatically cheaper than many calcium and alkalinity methods.

For reef tanks, temperature seems simple: set the heater to 78°F and move on.

Except that number is often fiction.

We've seen heaters miss by 4-6°F. A tank you think is 78°F could actually be 82-84°F. In our experience, heaters are often less trustworthy than thermometers, especially inexpensive electromechanical models with built-in dials.

We recently tested a variety of aquarium thermometers and probes against a surprisingly simple standard: ice water.

The question wasn't whether ice water is 32°F—we know it is when prepared correctly. The question was whether accuracy at 32°F tells us anything useful about performance around reef temperatures.

We had three big questions.

Did the algae disappear from the softy tank? Did the brown slime in the future LPS tank finally go away? And what exactly are we building toward?

The answer is mostly yes—but how we got there is the useful part.

Some reef gear solves major problems. Other gear is simply fun, practical, and makes us think, "That's actually pretty slick." The Avid Aqua Traveler falls into that second category.

Kalkwasser has been around forever for a reason. It is cheap, effective, simple in principle, and it can give us one of the biggest side benefits in reefing, which is a meaningful pH boost. Plenty of great tanks have run on kalkwasser alone or used it as part of a larger supplementation strategy.

We got a very specific question: if most reefers are not buying the whole middle range of salinity tools, what actually happens when we compare the cheap Amazon refractometers against a more expensive branded option?

Four months is where a reef tank starts telling the truth — not the honeymoon phase, but when the method gets tested by real conditions.

The 90/10 softy tank is doing exactly what we hoped.

ATI Straton X Review: Does This Ultra-Thin Reef Light Deliver? The ATI Straton X is one of the most interesting reef lights we have tested in a while. On paper, it sounds like someone designed a light for reefers who are tired of bulky fixtures, fan noise, harsh shadows, glare, and the never-ending obsession with raw wattage.

The 90/10 Method was never designed to find every possible way to build a reef tank. The goal is simpler and harder: create one repeatable path that gives a brand-new reefer the highest chance of success.

Flow changes as coral colonies grow. Aquascapes create flow shadows, dead spots, and weird turbulence. A setup that worked six months ago might not work now. And the frustrating part is that there is no simple little meter that tells us, “Yep, nailed it.”

Every reef lighting app seems to have one now: that little spectrum chart that moves when we slide channels up and down. It looks useful. It feels scientific. It gives us confidence that we’re building a better light profile than just eyeballing the tank. But the real question is simple. How accurate is it?

We put kalkwasser to the test because there were a few things we had been assuming for a very long time, and some of them turned out to be wrong. Not a little wrong either. In some cases, grossly wrong.

The big question was simple: can we actually make full strength kalkwasser at home, and if so, what does it really take?

This isn’t about some futuristic idea of AI someday helping reef tanks. This is happening right now with real tanks, real problems, and real results

For a lot of us, the barrier to making a custom sump is not the concept. It is the execution. We can plan chambers. We can picture where the skimmer goes, where the return goes, and where the refugium lives. But getting acrylic cut cleanly, making sure dimensions are right, and ending up with something that does not look like a garage experiment gone wrong is where the project can fall apart.

AI in reefing is one of those topics that gets people fired up fast.

It touches everything: experience, expertise, community, even ego. Some reefers don’t like the idea that a machine can answer tank questions. Others have seen AI get things wrong and written it off completely.

Most people start reef tank shopping with the wrong question: What brand should I buy?
A better question is: What features actually matter for how I reef?

That shift changes everything. It moves us away from polished marketing and toward performance, maintenance, and long-term satisfaction. Get this right, and we save money now while avoiding years of “why didn’t I think of that?”

Hydrogen peroxide dips are one of those reefing tools that can be incredibly useful, but also far more aggressive than standard coral dips. That is exactly why we tested them on five soft corals and mushrooms to see what actually happens.

The goal was simple: compare duration versus concentration, identify which corals tolerate peroxide, and determine if it is a practical way to remove algae, worms, and other pests before adding frags to a tank.

At serious reefs, the goal has always been simple: deliver real, useful information that helps reefers succeed. This latest update is all about making that experience better with a more consistent schedule, clearer content focus, and structured giveaways that reward the community.

Salinity seems simple… until you realize how easy it is to get wrong. Between refractometers, calibration solutions, temperature, and technique, it is surprisingly easy to feel confident in numbers that are not actually accurate. In this SR Labs test, we put three popular refractometers and multiple “reference” solutions to the test to answer one question: What can reefers actually trust?