Substrate replacement method

[CoralKing]

I’m thinking of changing the substrate of one of my tanks, and was wondering if anyone has ever done this with fish/live rock in the tank? Should I remove the LR and fish before I replace the sand? Is it possible to do this while the LR and fish remain in the tank? (I'm thinking of replacing with CaribSea arag sand)

Thanks

 

[Pandafish]

I have read you can do half or third at a time...remove substrate and pour the sand down to the bottom through a large PVC pipe.

I just did my tank... I removed everything. Fish and Clean up crew to the QT tank.
Drainded the tank to 5 gal buckets. Live rock into the buckets. Removed the CC and scraped the algea. added the "live" sand and set the rocks. Filled with water from the buckets. I used a mag 7 outlet hose on to a plastic plate to keep the "dust" down. Waited 24 hrs...tested chem. 10% water change and returned fish and clean up crew. All good.

Keep in mind if you are changing from CC that sand does not support the live rock. On my large rock I used a saw with a masonary blade a sawed the bottoms flat. Just placed the LR on a clean towel a zip less then a minute and into the tank.

Good Luck

 

[Cody Ray]

If you have a decent amount of liverock than you shouldn't have an issue just removing all of the sand and replacing it. It won't hurt to have a little of the old sand remaining. Just be ready to do a couple decent water changes just in case.

 

[CoralKing]

Thanks for the responses. The tank currently has crushed coral, but nitrates have been high for a while. I'm thinking of replacing it with sand to help with the nitrate control. Do you think placing a thin layer of sand over the CC would help with nitrate control (as opposed to removing the entire substrate)?

Thanks

 

[Cody Ray]

No. Detritus is still trapped in the cc. If you have cc than you could remove it all at once as it doesn't have any ability to process nitrate therefore it won't add to you nitrates. However I would recommend removing everything from the aquarium including the water so that when you remove the cc you don't release detritus into the water. I would liken this to removing a filter pad from a filter. It is full of detritus and lifting it out of the water will dump some of that detritus back into the water. As to how much sand you add it depends on the grain size. The sand you are talking about works well for a 1-3" bed. I have read recent articles that suggest that denitrification can occur in as little as a centimeter of sand (this refers to sugar sand). I would say that would will get good results from a depth of roughly 3". Anything more than this would be a waste of sand unless you plan on keeping a jawfish, seagrass, mangrove, etc. After the first 3" or so of substrate the denitrifying ability of the bacteria is greatly reduced as Nanaerobic bacteria can tollerate and even benefit from a small amount of oxygen. If you want you could go the full 4" and keep the first inch stirred in order to prevent detritus from slowly finding its way into the deeper regions of the sandbed. IMO this works best in high flow aquarium because the first inch or two experience an almost fluidized state (many call this a sand storm but in nature sand naturally moves around the reef from high flow to low flow regions. New sand is created in the high flow regions because of the wave action with replenishes the constantly moving sand).

 

[LFS_worker]

remove 90% of the water into rubbermaids the just remove the sand however you can ... do this as fast as possible and make sure there is no sponge on the rock ... replace the rock and fish test 48hrs later if all tests well add new sand...

at work we do about 2 of these a month with awesome results ... its really a 10% water change but the bottom 10. good luck and be ready to do some water changes in 48hrs.

B

 

[Pandafish]

<a href=showthread.php?s=&postid=7867178#post7867178 target=_blank>Originally posted</a> by LFS_worker
remove 90% of the water into rubbermaids the just remove the sand however you can ... do this as fast as possible and make sure there is no sponge on the rock ... replace the rock and fish test 48hrs later if all tests well add new sand...

at work we do about 2 of these a month with awesome results ... its really a 10% water change but the bottom 10. good luck and be ready to do some water changes in 48hrs.

B

I used a wet dry shop vac...last 10% water and CC less than ten Minutes!

 

[CoralKing]

After removing the existing substrate and the last bit of water, should I put the new sand into the tank? It sounds like I should replace the rock and fish, and add the sand at a later time?

 

[lakee911]

Sorry, don't mean to hijack, but I'm going to be doing the same. Replacing CC w/ Sand. I'm thinking I will remove half the rock to some totes and then suction 1/2 of the CC out of the tank. It'll take ditrius with it.

I'm at a loss on how to get the sand back in the tank. I will probably go with a silica sand, just because of the cost. If I rinse, I'll get any bad stuff out of the sand, but it'll take forever for like 250LBs and I'll losethe fines, and then it's all wet. How do I get back in the tank?

Maybe not rinse, and pour it dry down the PVC pipe? Will probably still be cloudy as all get out, right?

 

[Hobster]

Coralking,

You never mention what size tank or how much sand you are going to add.?

When I replaced sand in one of my tanks, I first rinsed it 3 times. I then let it sit in a Rubbermaid container filled with fresh saltwater mixed with several gals of tank water. Ran a small power head to keep it aerated. After a week or so the bacteria will help hold it together and you will not have a big sand storm in your tank.

Now drain your tank, take everything out, put the new sand in and cover it with a clear piece of plastic or large trash bag. (this will keep down the sand storm) pump about half your water in. Carefully remove the plastic. Add rocks, coral etc and then add the rest of your water.

Presto, chango, new tank

Good luck and have lots of buckets and towels.