crushed coral replacement question

[Wael El-Dasher]

When I set up my DT, the LFS sold me crushed coral substrate and only put down about 2" worth. I asked him several times about using crushed coral and he pointed out that he's been using it for years and years in his tanks and never had a problem. When I mentioned that most websites recommend 4" of substrate he gave the same justification.

Yesterday, I found a new LFS next to my house! They import aragonite live sand from California. I was delighted to see the buckets and buckets of this stuff in his store and planned on slowly replacing the crushed coral substrate in my DT.

But before I rush out and spend my hard earned money on very expensive sand, I wanted to check in with you folks.

Do you recommend I change the substrate from crushed coral to aragonite, or should I add 2" of aragonite on top of my crushed coral? Lastly, should I leave things alone?

I have a sump, I have no NO2, NO3 or NH4+ issues. My pH seems to be always steady at 8.3 (I use Aqua Medic Coral Salt) and everything is OK, except I always need to supplement Mg, while my Ca is always around 460-500mg.

I wasn't planning on removing the LR, whatever crushed coral under it will stay. It's just all the CC around the LR that will be replaced.

cheers

Wael

 

[Wael El-Dasher]

I've read a bit already about making such a swap, but wanted to hear from others of it's worth making the change based on what I wrote earlier.

 

[thominil]

Have you looked into just bagged plain dry aragonite sand? Much cheaper than any live stuff. Either way, replace the CC, since it may cause problems with trapped detritus which will lead to nitrate problems down the road.

 

[Wael El-Dasher]

That would be nice but the only one I can find locally is the live sand aragonite. It's sold in large buckets.

If I clean up the CC, would be ok to add the aragonite above it? Or is it not worth it? I thought it might be one way to bring up the substrate to 4" by adding 2" worth of the new substrate.

 

[thominil]

The CC would eventually make it's way to the surface and in turn, defeating the point of the aragonite. A 4" sand bed is not needed, 2" will do you just fine. You could have a bare bottomed tank if you wanted to. Aragonite is worth the switch IMO. Hope this helps a bit.

 

[Gregcoyote]

If it ain't broke, why fix it? Sounds like your tank is operating well and a big change like this could just as well backfire. What is your goal?

 

[Wael El-Dasher]

Well, I replaced the front half of the DT substrate. I bought 4 buckets of live sand and aragonite, each bucket has 2 bags which are 10lbs each.

I think the plan is to stop there. I don't want to upset the balance I've worked so hard to achieve. While the idea was to help avoid the issues many mentioned here regarding detritus trapped in the CC over time, I did feel the this new sand was not much smaller than the CC I've taken out. However its grains are a bit rounder. They seem like the same grain size to me.

On the plus side I did get rid of the red slime I had, and I built up the substrate upfront to about 3".

Here are a few pics after the swap.

Cheers

Wael