Question for those who use AFR Powder

Yates273 · Jan 5, 2026

I recently purchased more All for Reef for my Tank. I just mixed a batch at the ratio called for , 160g to 900 ML‘s of RODI water. I noticed after 10 minutes of mixing the AFR does not dissolve like it used to. This is the second batch I’ve noticed this happen to me. It almost like there’s too much AFR preventing it from dissolving with the 900 ml of water. I never had this issue with my previous containers just this new one.Is anybody else experiencing this?

D.WhiteShark · Jan 5, 2026

I got some about a month ago and do not have this issue

Yates273 · Jan 5, 2026

I emailed Tropic Maron and see what they have to say. I’ve never had this issue.

Yates273 · Jan 5, 2026

Upon further review and research, I’ve noticed my scale is off and that’s why, I’ve been putting too much in. That makes sense because I’ve never had an issue with AFR. OOPS!!

FUNGI · Jan 5, 2026

did you try warm water ? also, after mixing, you are supposed to add more water to make it 1liter.
Mine get like that also sometimes...never given it a thought......

Yates273 · Jan 5, 2026

Once I changed the scale to the proper measurement, it mixed up fine. I’m an idiot. Kind of thought I was putting too much, but I was going by what the scale said.
I usually put 900 mL of water to 160 g of AFR and never have an issue and like I said with the proper measurement, it mixed up fine. Stupid on my part.

KrisReef · Jan 5, 2026

Yates273 said:
Once I changed the scale to the proper measurement, it mixed up fine. I’m an idiot. Kind of thought I was putting too much, but I was going by what the scale said.
I usually put 900 mL of water to 160 g of AFR and never have an issue and like I said with the proper measurement, it mixed up fine. Stupid on my part.

Mistakes are easy, but admitting and publishing these kinds of pitfalls may actually help someone else down the road when this happens to them. Thanks on behalf of the unknown future "out of balance" reefer

To err is human.

LOZReefer · Jan 12, 2026

Good catch. FYI - I believe (going off of memory here), you mix it in 900ml water and then top it off to 1000ml (1L). IMO, it doesn't really matter how you mix it (in 1000ml or 900ml then add the last 100ml) but your solution is a slightly higher concentration if you do 900ml and don't top it off to 1000ml.

I find the best results when I can heat up the RO/DI water prior to/during mixing.

Randy Holmes-Farley · Jan 12, 2026

LOZReefer said:
Good catch. FYI - I believe (going off of memory here), you mix it in 900ml water and then top it off to 1000ml (1L). IMO, it doesn't really matter how you mix it (in 1000ml or 900ml then add the last 100ml) but your solution is a slightly higher concentration if you do 900ml and don't top it off to 1000ml.

I find the best results when I can heat up the RO/DI water prior to/during mixing.

The directions that I have and follow do not say to add anything more than the 160 g and 900 mL. It says that combining those will already make about 1 L.

To prepare the liquid mineral mixture, dissolve 6 level scoops (approx. 160 g) of Tropic Marin® All-For-Reef Powder in approx. 900 ml of reverse osmosis water, resulting in a total of 1 l of dosing solution.

LOZReefer · Jan 12, 2026

Randy Holmes-Farley said:
The directions that I have and follow do not say to add anything more than the 160 g and 900 mL. It says that combining those will already make about 1 L.

To prepare the liquid mineral mixture, dissolve 6 level scoops (approx. 160 g) of Tropic Marin® All-For-Reef Powder in approx. 900 ml of reverse osmosis water, resulting in a total of 1 l of dosing solution.

This is from Tropic Marin CEO in a post. Albeit, a couple years ago.

At the end of they day it's a pretty marginal difference but worth noting if you're super OCD about dosing accuracy.

Randy Holmes-Farley · Jan 12, 2026

Thanks for posting that. :)

I think TM needs to alter/clarify the way their web site is written (or perhaps translated).

In any case, I agree with what I forgot saying in the past about it not mattering much, since everyone doses to a target level (alk or calcium) rather than fixing on a specific amount.

In fact, I make mine up without the extra 50 mL, but do not literally even know how much I'm dosing, just how long the nominal 1.1 mL peer min doser runs each day. I adjust the time to ensure I meet my alk target, and have never calibrated if the 1.1 is accurate or not. lol'

areefer01 · Jan 12, 2026

Using a scale vs the scoop is important. In my opinion. Just makes it a lot easier vs human inconsistency of using the scoop. Can pack it in there vs normal weight and leveling off. Sort of like baking a cake from scratch and flour.

Just my experience using the product.

KrisReef · Jan 12, 2026

This is what I hate about chemistry. I thought that if the salt completely dissolved that the 900 ml would still be 900 ml, and no measurable volume change would occur?

I'll have another umbrella drink to help me think about this one.

KrisReef · Jan 12, 2026

Yeah, I am completely wrong
AI=
Why it Happens

Ion-Dipole Interactions: Salt (NaCl) breaks into positive sodium ions (

Na+cap N a raised to the positive power
) and negative chloride ions (

Cl−cap C l raised to the negative power
). These charged ions strongly attract the polar water molecules (dipoles).
Water Molecule Reorientation: Water molecules align themselves around the ions, disrupting their usual hydrogen bonding and packing more tightly near the ions.
Space Filling: The ions and tightly packed water molecules occupy the spaces that were previously between individual water molecules, leading to a net decrease in total volume.

Analogy
Think of filling a jar of marbles (water molecules) with sand (salt). The sand grains fill the gaps between the marbles, so the total volume of the mixture is less than the sum of the marble volume and the sand volume.

Key Points

Contraction: For table salt (NaCl), the volume usually contracts (decreases).
Not Always: Some salts, like magnesium sulfate (

MgSO4cap M g cap S cap O sub 4
), can cause the solution volume to be even less than the original water volume.
Small Effect: The volume change for table salt is small (around 2% for saturation) and often unnoticeable in everyday amounts, but measurable in chemistry labs.

ChrisfromBrick · Jan 12, 2026

this happens to me. I admittedly do not weigh it out of pure laziness and just do 6 sort of level scoops. The result is some sediment AFR at the bottom even after 20 min of spinning. Alk hasnt been affected as a result that I can see. Of note, I am also dosing Kalk all day and night.

Randy Holmes-Farley · Jan 12, 2026

KrisReef said:
This is what I hate about chemistry. I thought that if the salt completely dissolved that the 900 ml would still be 900 ml, and no measurable volume change would occur?

Depends on the salt and the amount. Volume can rise (sodium chloride), or even fall (magnesium sulfate) when dissolving different salts into water. Most of the time, the final volume is less than the combined volume of the two before dissolution.

A discussion of why is very complicated with several competing effects, but ions can attract water molecules, pulling them closer together, but ions also can take up space and may also disrupt hydrogen bonding, impacting total volume.