how to change substrate

I decided to modify my tank to be able to handle SPS corals and clams, ive upgraded lighting, added a refugium. There is one thing left that i cant find much information on and what i find is contradictory. Changing substrates in a existing aquarium.

right now I have between 2-3 inches of Crushed coral(I didnt know any better when i set tank up), and I want to ditch it if possible, and replace it with some sort of sand which is still TBD. (suggestions welcome)

1) is it safe to change substrate from crushed coral to sand?, or am I going to have to completly re-cycle my tank?

2) Do I replace it all at once?, or use plastic dividers to do it in sections? how many sections for a 55g tank?

3) is it worth the effort? or am I just looking for more things to do?


my tank is about 20 months old if that matters, and i have about 60 lbs live rock

 

Well a sand suggestion would be sugar sized aragonite. I think you will cause your nitrates to spike if you remove the CC. I would try siphoning the CC before I changed the sand.
I think if you treat the change like an upgrade and pull everything out into buckets with the tank water put in the buckets down to the level of your rock before you move anything and adding water from the tank as you are about to expose rock or coral and have 10 or 15 gallons new water prepared ahead of time you could do it with minimal interruption to the system.

 

What I would do is change about 1/4 of the tank at a time, You can try to siphon it out, but it that doesn't work, I would just remove it by using a cup or net to scoop it out. IMO, it is worth the effort and you will be much happier with the results.

 

+1 on changing in smaller sections

 

It is doable, plan it out and give yourself a 1 -2 week timeframe. start by vacuming the CC bed to remove as much excess detritus as possible. then leave it alone for a day and check your water parameters to make sure everything is ok. You can then procede to scoop out the CC in sections over a few days.
At this point your ready to pull your rock out and redo the aquascape if you want to, plan a whole afternoon so you have time to finish.
put all the rock in a tub with a powerhead and heater, clean out the last of the CC and then vacum any crap off the bare bottom of the tank. set the base course of rock on the bottom then add your sand all the way around the rocks to help set them firmly in place. let the cloudiness settle a bit then finish adding the rest of your rock back in.

The radical alternative is to simply do it all in a single day.

My recomended sand

 

i did this im my tank much smaller tank but i started to replace the cc bit by bit but there was way to much mess so i pulled evry thing out i saved about 75% of the water the rest i saved to rince out the tank once all the cc was out and i dident have much of a cycle

 

Hey, rdarris! Yes it's safe. As others have mentioned, it's all in how you do it. No, you don't have to completely re-cycle the tank. Some have mentioned vacuuming first, some doing it in sections. Both good ideas. I've done this before, and here's how. A warning beforehand, if you're in any kind of rush, stop reading here.

The first task was to move all LR to one side of the tank. I worked slowly, and when I was done, the single pile took up about 1/3 of the tank's left side, and came about 2/3 up to the top. I stacked very carefully so avalanches were avoided.

I used the clear, thick walled aquarium tubing such as what you'd use to attach your return pump. I used the 5/8" diameter stuff. When it was time for a water change, I simply siphoned the crushed coral right off the bottom in small sections. I worked slowly and carefully making sure that any sediment that became liberated during the "sweeping" was quickly sucked out by lifting the tubing off the bottom to catch the whisps of waterborne dust. These were kept to a minimum, though.

I probably took out less than a cubic foot per session, so it took maybe 5 or so "water changes" before I was done. When the right side of the tank was clean, I stacked the LR on the glass bottom C A R E F U L L Y, and worked on the left side. Long story short, in this fashion I didn't experience any change in any parameter. Each session had a bit more substrate out, replaced by clean, newly mixed water. It took awhile, but the ordeal was pretty light for my livestock--which was important. When I was finished removing the CC, the water was clear and the livestock was happy.

When it came time to replace the CC with sand, I worked equally slow, adding no more than a few handfulls at a time. Despite my best efforts, this DID create some dust, but it wasn't too bad, and my livestock didn't seem to mind.

Just go slow and you'll be ok. As mentioned above, it's a good idea to keep checking your ammonia, nitrites and nitrates as you go along, but if you go slowly, you should be golden.

Good luck!!

 

great information, and more importantly consistent information. one other interesting thing I was told at the LFS today was when putting the sand in, use a ziplock sandwich bag to move it to the bottom of tank and then you can put the sand down with less dust storming.

I've also got a small display fuge that only has some sand and cheato in it atm, where my more sensitive corals and BTA will live during the process, luckly for once, i thought ahead and I plumped it so that i can turn valves on DT overflow and fuge drain and completely seperate the fuge from the DT (using a 10 gallon rubermaid as a temp sump. yay old spare pumps and skimmers)

 

That is a fantastic idea with the plastic bags!!