Sandbed Swap Article

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Hi, in response to a discussion on another thread, I thought I'd give this its own space. I'm not sure if this is floating around here, so I thought I'd just refresh it:


You have a crushed coral sandbed, or perhaps a mixed substrate that has too many large particles to be as efficient at nitrate export as a sandbed of smaller grain size. Whatever the case, you want to swap to a DSB, using the much talked about HD (Home Depot) playsand from Southdown. Or perhaps you’re a maverick using silica sand. Lot’s of folks have, but we’re not here to debate silica/non-silica sand. There are many types of playsand, and the most important thing is that you don’t put anything BAD into your tank. I’m talking about sands with limestone, or any type of concrete sand. Don’t roll your eyes; some folks have done it.

So now you have your small particle sand and are wondering, what the heck do I do NOW??? There are so many ways, and you can drag the process out for longer than necessary. We won’t be going over the long-haul approach to mixing in/swapping out sand. We’ll be going over the one-day swap. If suspicious caution tips the scale over proven practice, STOP READING. There are plenty of folks who will cater to a one-month dragging out process. We’re ready to go to work and make this as easy as possible, without killing any inhabitants, and immediately transporting your beneficial bacteria/life while maintaining sufficient amounts during the transfer!

Again, there are many variations and you might make a few yourselves. Why not consider these basic guidelines:

· Make sure you have plenty of materials on hand. You’d be best off having another hobbyist on hand to help you out and make sure at least one of you has your head screwed on at all times! Things can get hectic, and you can work yourself into a corner if you don’t THINK. You’ll want to have plenty of fresh saltwater made up. Plan on at least 30% of your total tank’s volume. Have one pair of nylons (that’s right, panty-hose!) They’re not part of a kinky half-time show, just make sure you have some! Rubbermaid makes some excellent 20G trashcans, called Roughnecks. Those are perfect to have your fresh water mixed in the night before. You will also want enough of them to store your live rock. Yes, get over the thought of leaving your rock in and somehow changing enough sand/substrate out. This process is going for the total swap! No matter how big your tank size, remember that 30% fresh water makeup. Don’t skimp, you may or may not need it, but you’ll kick yourself if you have foul water you have to add back. We’ll cover that later! Make things really easy and have a strong pump to return water into your pump, and have plenty of hose to do it. The 20G Roughnecks are perfect, because you can mix the water up in the kitchen/garage, yet two people can still move one full of water to the tank when you need it. Worried about netting your fish? Don’t. This particular process doesn’t do that. We think it more stressful on the fish to yank them than to just leave them behind. We’ve never floated a fish yet by changing their environment. Still, have that net/hospital box on hand. You might have a fish that really starts looking bad, or so stressed it won’t even swim away from your hand. We’ve never had this happen, but you still want to BE PREPARED. If a fish won’t swim away from your hand, I’d scoop him up in a clear hospital box and transfer him to one of your freshly made batches of saltwater. I can’t go over every little bit of common sense; I’m hoping you’ll have more than I do! Have a couple of cheap heaters set to maintain 80F. You’ll need these in your live rock tubs later. Make sure you set them at 80F so they are ready to go when you need them. If you have a heater in the made up water, great. If not, you can always add boiling water and bring it to the right temperature when you need it. The most important thing is that the salt is dissolved. If you have powerheads to keep circulation, that's great. If not, you can keep it agitated every half an hour or so with really vigorous stirring using a long stick/spoon. Be creative! Have plenty of towels on hand. Not paper towels, but plenty of old bath towels. Have at least one floating glass hydrometer. This will allow you to quickly take temperatures and measure salinity. If you are not using heaters in your makeup water, mix a bit more salt than necessary, because you’ll be adding hot water later to bring it to temperature. Okay, ready to start!!

· The hardest part is the preparation. Trust me. Now everything goes quickly. You already have plenty of fresh makeup water to put back in the tank, and you have a lineup of empty Roughnecks at your disposal. Enough buckets are critical. You know how big your tank is, and you’ll want sufficient buckets to dump your old substrate in.

· Start by powering down your system. Don’t worry about the heater being in the sump. It is safer down there while you’re moving your rock, and this won’t take too long.

· Next, remove any corals and keep them in a separate small tub with your pre-calibrated heater and a powerhead. You don’t want to be piling your live rock on your prize corals. Next, take out your live rock and put it in one of the garbage cans. Fill it ¾ full, and have another garbage can if you need one. Once you’ve reached ¾, siphon enough water out to cover all the rock. Move the garbage can out of the way. Remember the heater you set for 80F? Make sure that’s in the can. If you have a powerhead, that’s great too. Not necessary, but certainly a proper thing to do!

· Now would be a great time to either put one of your extra heaters in the main tank, or put the one from your sump in the tank.

· Once you have removed all your live rock, and the tubs are not crowded in your work area (aren’t you glad you had plenty of towels on hand??) you can scoop the old substrate out. You’re the creative genius of your household, so you figure out what you have to use to scoop it with. Remember the nylons? For every 50G of tank, make about 6 nylon balls of substrate. Make them the size of softball, and you’ll be fine.

· Hey, now your tank is empty of substrate and rock! It probably looks pretty foul down near the bottom, right? Grab that brush and go to work. By now your fish know you’re up to no good, and this shouldn’t alarm them any more. Besides, they’re really familiar with this practice because you faithfully clean your tank, right? Your water might be real cloudy. You have 30% fresh made up, right? So do the math and figure out how much you have taken out to fill your live rock tubs. If you have only used 10% of your volume, take another 15% out. You want to try and gauge this so you have some extra just in case. Remember, your rock had some water displaced, so keep that in mind when figuring out how much more to siphon out.

· Now it’s time to add the new sand. There are a lot of variations of doing this, so choose your weapon! You might pour it down a PVC pipe, or you might pour it over an upside down bowl. Don’t be totally inconsiderate of your fish and just go dump it in. You may have rinsed your sand, or you may not have. Some say rinsing it removes sedimentary particles necessary. There’s no doubt that they are indeed beneficial, but we’ve done it both ways. Either way, if your using a light aragonite sand your water will be cloudy. The silica sands will settle faster. Now would be a great time to add a few pieces of large lace/bowl rock. You can usually find them dry in a bin at your local fish store. Rinse them very well with a high-pressure garden hose nozzle. You can make some awesome caves, which will support your live rock on top.

· Now that your sand is in, you’re ready to go! Aren’t you real glad you have all those towels? Your water might be so cloudy that you can’t see 1 into the tank. If you are planning a real technical sculpting job, you might want to wait till the water clears up. This could be the next day, if you really want total clarity. If you have a built up scum from the new sand, scoop it off the tank surface with your net. You can line the net with shredded cotton balls to make it more efficient. If your rock is piled towards the back, or in the middle, you can usually add it back in just fine despite the poor visibility. The bottom pieces are the last pieces you took out, and are on the top of your live rock bin. If you used two or more, work logically (the last pieces out are the first pieces back in). Now is a great time to shake the rocks gently in the water as you pull them out. This will remove any built up sediment. Don’t worry about the water, as you won’t be adding it back to the tank. That’s why you have plenty of makeup. You may want to keep your corals separate for now, in their heated bin with a powerhead. Now that your rocks are back in, you can add the water. The 20G Roughnecks are perfect, as you can move them full of water (requires some muscle, which is why you have a friend to help). That pump and hose make this real easy. Now’s a good time to go with a flashlight and inspect your bins which were previously storing your live rock. Look for any shells that might have crabs. If you see a shell, add it to your tank. Don’t try to figure out if there is crab in there. There probably is, or it wouldn’t have fallen off the rock. See any prize worms? Toss those back in, too!

· Remember your softballs of substrate? Bury those about halfway into the new sandbed, spaced apart in the new sandbed. I’d leave them in for about two weeks, moving them around a bit every other day. This will maintain your bacterium while seeding the new sandbed. During this two weeks, gently stir the new sandbed with a long wooden dowel to help evenly form the biofilm. When you’re ready to pull the softballs, do so gently. You may have developed some small holes by escapees or curious fish. By virtue of design, the nylons will hold together well.

· Well, this is just a first edition, and I may have left something out. If it’s just another variation, that’s not a problem. Remember, there are a lot of different methods. But I think we’ve covered the basics. You know how to fill in the blanks, such as putting your heater back in the sump, turning your system back on, etc. Don’t forget your corals, in their separate bin, either. You do want to get those back in your system as soon as possible.
· As the system clears, you may want to rearrange some rock. Since you’re new to this whole sandbed thing you might be confused as to the constant dusting you’ll be seeing on your live rock. Not to worry, it will all eventually settle. Have a turkey baster on hand and baste from the top, working your way down to clear it every now and then.

Hey, this is just one of many ways to go about it. I’m sure there are a hundred variations, which many of you have been successful with. That’s great! This is for the person who has never done it yet, and wants to do it in a day if possible. It is possible, and we’ve just outlined how! Good luck, and I hope this is a good guideline of some important steps along the way to replacing your old cc substrate!

Monty C.,
Fish Whisperer


Good luck with the swap, hope this helps a bit!!