[Clay12340]

I am a little foggy on the ups and downs of the various particle sizes of available aragonite sand.

From what I've been able to gather there are three main factors that influence the choice: Surface area, ease of disturbance, and livestock needs. Smaller particle size means more surface area, but it is more likely to be disturbed by high flow. Larger particle size is just the opposite. Would a base of small particle sand with a thin layer of larger grain sand not be the best of both worlds?


I'm currently using a larger particle size and am planning to add another inch and a half or so to the sand bed, but would like to use a smaller particle size for small burrowing fish(shrimp gobies) and looks. Is there any downside that I'm missing?

I was planning on just adding the smaller grain sized sand and as the larger particles rise to the top removing them gradually. Does this pose any dangers or downsides that I should be aware of?

[kevinpo]

I prefer .2 - 1.2 mm size. If the particle size gets too large then they will trap detris, waste, and uneaten food particles around them. Then you have to use a gravel vacuum to keep it clean or live with higher nitrate levels. A small amount of larger size will not be a problem.

HTH,
Kevin

[Reefland]

I agree with Kevin, and would go with the smallest particle size available. too much larger sized particles on top (more than just scattered, causing a complete layer) will trap detritus and therefore I would not recommend it.

[Clay12340]

I guess I hadn't considered the detritus trapping issue. That might explain why my sandbed has such a massive bristleworm population.

[weez1959]

I'm kind of butting in but is it possible to add an inch or 2 of sand on top of CC in an already established tank that's been running for 9 months with fish and coral? Should this be done all at once or slowly?
Clay12340: Are you using CC right now?

[dibenni]

i am no expert - but i don't think that is a good idea. a lot of waste gets trapped in crushed coral and can cause a nitrate spike.

[kevinpo]

The larger particles will quickly (within 6 months or so) rise to the surface and you will have the same problem with trapped detritus.

Regards,
Kevin

[weez1959]

ah, ok got it, so the only way would be to tear down the tank and change it huh?

[Ninong]

Originally Posted by Clay12340

I am a little foggy on the ups and downs of the various particle sizes of available aragonite sand.

Dr. Rob Toonen has investigated this question. You can read the abstract here.

He discussed his experiment here and here.

[kevinpo]

ah, ok got it, so the only way would be to tear down the tank and change it huh?

No, not at all. I have done several changeovers. I used a 3/4" hose and siphoned out the gravel a section at a time. On a 6' tank I did 25% at a time and replaced it with the smaller substrate. When adding the new substrate I filled a couple pound container and held it just under the waters surface until it stopped bubbling (was completely wet). Then set it on the bottom and slowly tipped it over and let the substrate run out. There is only a slight clouding which clears in 4-5 hours.

HTH,
Kevin

[Clay12340]

Weez my substrate is already aragonite sand, but I believe the particle size is 1-2mm. I am wanting to change, because I like the look of the finer sand, and because I am planning to add a small shrimp goby to the tank which is a burrower and I've seen recommendations for smaller smoother sand.

Ninong thanks for the link. Very informative and told me exactly what I needed to know. I suppose now I've got more reasons to want to move to smaller particle size than just aesthetics and fish preference.