How do I stop the sand from shifting?

bbrantley · 02/27/2006, 08:34 PM

Hey all,

I've had my 225G up and running for almost six months now. It has a healthy assortment of live rock, fully encrusted at this point, and about 100 crabs and snails keeping things tidy. It's totally ready for fish, inverts, and corals, but I'm not in a hurry.

Anyway, the biggest problem is that I have two Tunze 6100's in the tank to produce lots of flow. They work GREAT, and they're quiet, and I love 'em. The problem is that I cannot for the life of me figure out how to avoid them blowing my 200 pounds of Southdown sand around.

I've positioned them in a variety of different arrangements, and I've even tried tilting them at an angle so they blow "up" a little bit. I've come to the realization that the sand gets blown out of whatever wall they point at -- that is, the flow hits the opposite wall and goes up and down. The up part just makes ripples on the surface, but the down part slowly digs the sand down to the acrylic bottom of the tank.

I started out with 5 inches of evenly distributed sand. Now I have 7 inch mountains in the middle and bare acrylic on the corner. I'm hesitant to move it around too quickly since I know there is an anoxic layer that will be disrupted when I do, but I guess I'll have to at some point. More importantly, I have a giant 100-pound piece of live rock that depends on the sand bed to hold it upright, and its ability to stay standing is getting pretty sketchy!

Does anyone have any suggestions? Is it unusual to have this problem?

Thanks,

Ben

Qwiv · 02/27/2006, 09:04 PM

First: Do something with that live rock. Your sand should NEVER support your liverock for (2) reasons:
1- the rock can get undermined and fall BAD.
2- it creates a area of compaction in the sand. The critters in the sand cannot live in this part of the sand so it becomes a dead spot. The sand will most likely clot and form a dark black area in the sand. BAD.

Cut a piece of 2" or so PVC pipe and support the LR with that. The PVC rests on the bottom of the tank like a cup and holds up the LR. Sand settles all around the PVC.

To keep the sand bed steady at the end of the tank you can:
- Possition the Tunze so the turbulance is the greatest at the high part on the liverock at the opposite side of the tank. The corals will love this later.
- Put some rubble or crushed coral at the ends of your tank
- Turn the Tunzes down until you have more coral. The coral will restrict the flow much more later. You don't need 100% of the flow at the moment.

I do all three of these things in a 180 gal with (2) 6100 tunzes, and ampmaster 3000 on a closed loop and a T3 return pump. IT works pretty good. I also have a few burried pieces of base rock that act as breakwaters. I put them in there because I wanted to change the elevation of the sandbed in diff. parts of the tank. It worked really well. My engineer goby does mess it up a bit however.

jfloydr · 02/27/2006, 09:32 PM

Take out the sand. Southdown is hard to get to stay still with tunzes in there.

Alaskan Reefer · 02/28/2006, 05:22 AM

Southdown and Tunzes is a tough pair to match. I use "reef sand" and "pink flamingo" from Carib Sea just so I have large enough grain size to prevent my 6060s from blowing it all over my 125. Still, I have a couple of drifts (none bare, but close), which I combat with the pink flamigo (has some larger pink rocks in it) and carefully placed branches of live rock as breakwaters. I know it wouldn't work with Southdown, though -- too fine. Plus, I like to siphon my sand during water changes so Southdown definitely isn't for me...

NCreefwannabe · 02/28/2006, 01:23 PM

i have southdown sand in my 55, 4 inch deep. it has 1240 gph going through it.. Not sure what that is in comparison to your setup, but I have my powerheads on the sides pointing slightly up and at the front glass. It moves only the very top sand until it cant anymore. now it only moves other stuff that may be on top which is what you want anyways.

WaterKeeper · 02/28/2006, 01:40 PM

I would think by now that the sand would have enough biological growth to keep it in place. I'm making a guess here but I suspect the crabs. They do love to eat and without much in your tank may be subsisting on the biofilm that tends to cement the sand grains together. You can try seeding the play sand with some real LS or you might consider setting up a crab tank.

bbrantley · 02/28/2006, 03:01 PM

Thank you all for your helpful replies. A few responses:

1. I do have the Tunze's down to about 35%, and they still produce plenty of flow to pick up the sand (slowly, over the course of months). Yeesh!

2. The "breakwaters" and rubble sound like excellent ideas. I had not thought of those!

3. Tom, the crabs went in about a month ago, 5 months into the live of the tank. Alas, the sand was getting blown quite readily before they arrived. I did get the biofilm, at least at the top of the sand, after about a month and things settled considerably.

I will try moving the sand (slowly, over a course of several days) back into something reasonable, making another slight reposition of the Tunzes, and applying some live rock bits and/or coral rubble in the worst corner for erosion and see what happens.

I'll follow up here with the results, in a few months.

Thanks,

Ben

Qwiv · 02/28/2006, 05:28 PM

And get a fish or coral in there for gosh sake!

bbrantley · 02/28/2006, 06:19 PM

Ha ha, good point. I'm eager to get all the logistical stuff "fixed" before I start adding life that I have to take good care of. Fortunately, I'm down to some plumbing shenanigans, some hood issues, and this blowing sand thing. Once I get those ironed out, it's full speed head for the stocking!

Ben

Qwiv · 02/28/2006, 07:18 PM

Still stock slow. But your tank sounds ready for a fish while you work the other issues out.

NCreefwannabe · 02/28/2006, 10:26 PM

yea i didnt think about the crabs. I got rid of my crab for that very reason... 1 day after he was gone my cloudines stoped

02/27/2006, 08:34 PM	#1
bbrantley Premium Member Join Date: Jun 2005 Location: Boulder, CO Posts: 478	How do I stop the sand from shifting? Hey all, I've had my 225G up and running for almost six months now. It has a healthy assortment of live rock, fully encrusted at this point, and about 100 crabs and snails keeping things tidy. It's totally ready for fish, inverts, and corals, but I'm not in a hurry. Anyway, the biggest problem is that I have two Tunze 6100's in the tank to produce lots of flow. They work GREAT, and they're quiet, and I love 'em. The problem is that I cannot for the life of me figure out how to avoid them blowing my 200 pounds of Southdown sand around. I've positioned them in a variety of different arrangements, and I've even tried tilting them at an angle so they blow "up" a little bit. I've come to the realization that the sand gets blown out of whatever wall they point at -- that is, the flow hits the opposite wall and goes up and down. The up part just makes ripples on the surface, but the down part slowly digs the sand down to the acrylic bottom of the tank. I started out with 5 inches of evenly distributed sand. Now I have 7 inch mountains in the middle and bare acrylic on the corner. I'm hesitant to move it around too quickly since I know there is an anoxic layer that will be disrupted when I do, but I guess I'll have to at some point. More importantly, I have a giant 100-pound piece of live rock that depends on the sand bed to hold it upright, and its ability to stay standing is getting pretty sketchy! Does anyone have any suggestions? Is it unusual to have this problem? Thanks, Ben

02/27/2006, 09:04 PM	#2
Qwiv Persistant Perspective Join Date: Nov 2003 Location: Belmont, CA Posts: 2,168	First: Do something with that live rock. Your sand should NEVER support your liverock for (2) reasons: 1- the rock can get undermined and fall BAD. 2- it creates a area of compaction in the sand. The critters in the sand cannot live in this part of the sand so it becomes a dead spot. The sand will most likely clot and form a dark black area in the sand. BAD. Cut a piece of 2" or so PVC pipe and support the LR with that. The PVC rests on the bottom of the tank like a cup and holds up the LR. Sand settles all around the PVC. To keep the sand bed steady at the end of the tank you can: - Possition the Tunze so the turbulance is the greatest at the high part on the liverock at the opposite side of the tank. The corals will love this later. - Put some rubble or crushed coral at the ends of your tank - Turn the Tunzes down until you have more coral. The coral will restrict the flow much more later. You don't need 100% of the flow at the moment. I do all three of these things in a 180 gal with (2) 6100 tunzes, and ampmaster 3000 on a closed loop and a T3 return pump. IT works pretty good. I also have a few burried pieces of base rock that act as breakwaters. I put them in there because I wanted to change the elevation of the sandbed in diff. parts of the tank. It worked really well. My engineer goby does mess it up a bit however. __________________ If I knew keeping fish would be so hard, I would of had kids by now. Current Tank Info: 50Cube + 250DD + Nano

02/28/2006, 05:22 AM	#4
Alaskan Reefer Registered Member Join Date: Oct 2003 Location: Eagle River, Alaska Posts: 2,360	Southdown and Tunzes is a tough pair to match. I use "reef sand" and "pink flamingo" from Carib Sea just so I have large enough grain size to prevent my 6060s from blowing it all over my 125. Still, I have a couple of drifts (none bare, but close), which I combat with the pink flamigo (has some larger pink rocks in it) and carefully placed branches of live rock as breakwaters. I know it wouldn't work with Southdown, though -- too fine. Plus, I like to siphon my sand during water changes so Southdown definitely isn't for me... __________________ Unattended children will be given double shot espresso and a free puppy. Current Tank Info: 125g FOWLR -- Conversion Back To SPS In Progress

02/28/2006, 01:40 PM	#6
WaterKeeper Bogus Information Expert Join Date: Oct 2000 Location: SW Ohio Posts: 16,147	I would think by now that the sand would have enough biological growth to keep it in place. I'm making a guess here but I suspect the crabs. They do love to eat and without much in your tank may be subsisting on the biofilm that tends to cement the sand grains together. You can try seeding the play sand with some real LS or you might consider setting up a crab tank. __________________ "Leading the information hungry reefer down the road to starvation" Tom Current Tank Info: 130 Now out of service and a 29

02/28/2006, 05:28 PM	#8
Qwiv Persistant Perspective Join Date: Nov 2003 Location: Belmont, CA Posts: 2,168	And get a fish or coral in there for gosh sake! __________________ If I knew keeping fish would be so hard, I would of had kids by now. Current Tank Info: 50Cube + 250DD + Nano

02/27/2006, 09:32 PM	#3
jfloydr Registered Member Join Date: Jul 2003 Location: Salem, VA Posts: 1,427	Take out the sand. Southdown is hard to get to stay still with tunzes in there.

02/28/2006, 01:23 PM	#5
NCreefwannabe Registered Member Join Date: Jan 2006 Posts: 953	i have southdown sand in my 55, 4 inch deep. it has 1240 gph going through it.. Not sure what that is in comparison to your setup, but I have my powerheads on the sides pointing slightly up and at the front glass. It moves only the very top sand until it cant anymore. now it only moves other stuff that may be on top which is what you want anyways.

02/28/2006, 03:01 PM	#7
bbrantley Premium Member Join Date: Jun 2005 Location: Boulder, CO Posts: 478	Thank you all for your helpful replies. A few responses: 1. I do have the Tunze's down to about 35%, and they still produce plenty of flow to pick up the sand (slowly, over the course of months). Yeesh! 2. The "breakwaters" and rubble sound like excellent ideas. I had not thought of those! 3. Tom, the crabs went in about a month ago, 5 months into the live of the tank. Alas, the sand was getting blown quite readily before they arrived. I did get the biofilm, at least at the top of the sand, after about a month and things settled considerably. I will try moving the sand (slowly, over a course of several days) back into something reasonable, making another slight reposition of the Tunzes, and applying some live rock bits and/or coral rubble in the worst corner for erosion and see what happens. I'll follow up here with the results, in a few months. Thanks, Ben

02/28/2006, 06:19 PM	#9
bbrantley Premium Member Join Date: Jun 2005 Location: Boulder, CO Posts: 478	Ha ha, good point. I'm eager to get all the logistical stuff "fixed" before I start adding life that I have to take good care of. Fortunately, I'm down to some plumbing shenanigans, some hood issues, and this blowing sand thing. Once I get those ironed out, it's full speed head for the stocking! Ben

02/28/2006, 07:18 PM	#10
Qwiv Persistant Perspective Join Date: Nov 2003 Location: Belmont, CA Posts: 2,168	Still stock slow. But your tank sounds ready for a fish while you work the other issues out. __________________ If I knew keeping fish would be so hard, I would of had kids by now. Current Tank Info: 50Cube + 250DD + Nano

02/28/2006, 10:26 PM	#11
NCreefwannabe Registered Member Join Date: Jan 2006 Posts: 953	yea i didnt think about the crabs. I got rid of my crab for that very reason... 1 day after he was gone my cloudines stoped