Adding a DSB to an established reef?

[fishy929]

I really want to add a DSB to my reef. I am considering removing my gravel substrate and replacing it with 4-5" of southdown mixed with some live sand. What type of negative impact, if any, will this have on my reef inhabitants? Will it kick off another cycle?

[fishfreek]

Removing the existing substrate could cause an ammonia increase for the short term if to much of the existing substrate is removed to quickly. I avocate doing this kind of change by doing only 1/2 of the substrate at a time.

Depending on your inhabatants you might want to move them to a quarinteen enviorement while your working in the tank.

What are your inhabitants?

[fishy929]

FF,

My inhabitants are:

2 Percula Clowns
Humu Trigger
Yellow Tang

Bubble tip anenome
2 Skunk cleaner shrimp
dozens of snails and crabs

I don't understand why removing the substrate would cause an ammonia spike. Please help me understand Would I be better off just adding southdown on top of what I have (corse white sand)?

[fishfreek]

What kind if filter are you running.

75% if not more of the ammonia consuming bacterea live in your substrate and on your decorations. Thus removing all of the substrate will put a significant hit on your bactera population.

Adding sand on top of existing substrate can be dangerious in that if you bury the existing bactera to quickly it can be deprived of oxygen and die thus again providing you a low oxygen enviorment.

[Gauge]

How do all those things live with your trigger? I've known triggers to kill just about everything that can't kill them.

[fishy929]

I'm not running any mechanical filtration aside from carbon periodically to polish the water. I used to run my Emporer 400 but I removed the media and biowheels at least a month ago. It is running now primarily as a source of water movement. I have 75lbs of LR in my 55g reef for bio-filtration and I run an Aqua C Remora skimmer. Does that help?

[fishfreek]

The bulk of your ammonia and nitrite consuming bactera will be in the LR and on your substrate. Thus removing all the substrate at once would be like taking out all your live rock in one day but keeping your bioload and not adding any more filtration.

Doing only 1/2 of your tank at a time will allow the bactera to recover with only a minimal if even noticable jump in ammonia.

After two weeks you can then safely remove the rest of the substrate and complete the transition to a DSB.

[HoopsGuru]

One other method I have used with success is to place the old substrate into filter bags and keep them in the tank to seed the new substrate.

[fishy929]

Wow! Thanks for the great suggestions! I must admit that I already removed a good portion (10-20%) last week as I am fighting cyano like the dickens. I've lost alot through manual removal of large patches.

So, is it not recommended to mix some live sand with the southdown in this situation? I'm not sure how "live" the LFS version is, however. Maybe seed with some sand from an established reef?

How do all those things live with your trigger? I've known triggers to kill just about everything that can't kill them.

Well, I got him as a youngster and keep him very well fed. So far, he looks at the cleaners as beneficial (he's always in line for a cleaning) and he did taste test all my corals in the begining, but not since. I keep a close eye on him. I may seperate him out and start a new FOWLR after he gets a little bigger. For now, my Yellow Tang does a good job of keeping him in line