Flow in a BB system?

[Maxx]

How I love those with the center overflow ... why didn't they make them like that before?

This an old school Oceanic tank (Made before Oceanic was bought by All Glass). It wasnt a RR tank, (this one was made before they were selling them) so I had it drilled and had IAP make me an overflow. Its actually a little offset, more on the right side of the tank as you face it, than the left. But I can see how you mean the overflow is the issue. Usually after I use the Maxijet to blow detritus out of the rockwork, I try and siphon it up and back through a filter sock to remove as much crap as possible. I dont intend to keep the filter sock on the drain once the tank matures and the rock quits shedding as much. All of my rock was in a 55 gallon tank in the basement for about 6 months cooking. The 55 had an Aqua-C Remora skimmer hanging on it and a couple of powerheads to keep moving the water around. I never did a water change on the rock tank, nor did I really blow it off when it was in there. I probably should have, it might have reduced the amount of crap that comes out of some of the rock now.

I have designed everything that goes into this tank with flexibility and stability (not two things usually in the same sentence, but I swear its true) in mind. Flexibility in regards to being able to adjust things for the better, and stability in terms parameters. I want this tank to be rock solid with its parameters. I want to be able to go on a two week vacation with my fiance and be able to tell whoever house sits our dogs to feed the fish tank "X amount daily." I want to know that barring a natural disaster of Tsunami proportions, things will be fineeven if I'm not there to monitor the tank every day.

I'll be thinking Maxx ... just wish we could visit each other's tanks and learn so much more that way. Though we'd probably end up talking about corals and drinking too much beer

I'm not seeing a problem with this. When can ya come over? I'll even buy the first round.

Nick

 

[BCT182]

Hey Nick, In my 20g long I have one weak powerhead 20 gph in the bottom corner of the tank directed strait forward. It swirls junk all the way around three side of the tank and to a corner where I can siphon out. Then I have two 1200 gph powerheads in each corner facing the sides of the tank to roll of the side and bounce down into the rocks. For me, that has worked well.
Brett

 

[Maxx]

Very cool. Do you have any pics?
Nick

 

[BCT182]

I can post a pic tonight. Ill be back around 6:30.

 

[Maxx]

Hmmm......not really happy with this info.....

I just hooked up the new sump return plumbing which will run through my chiller....
Running my Iwaki 40 RLT pressure pump which is rated at 750 gph at 4 feet of head is running at 375 gph in this configuration. Just to be on the safe side I hooked up the Mag 950 that the previous owner of the chiller threw in for free when I bought it from him. He supplied receipts showing he'd purchased them both at Premium Aquatics in May of 2004. The Mag 950's performance was even more dissapointing coming at 250 gph, roughly 1.5 times less than the Iwaki. I was pretty sure the Iwaki would push more water than the Mag 950, but I just wanted confirmation.

It doesnt look like I'll be getting enough flow to push out the area directly in front of the overflow box. But I can actually hit that easier with the siphon than the areas on either side of the overflow behind the rockwork.

Hmm......might be looking at using some of those extra Maxi jets I have lying around to flush those corners out right.

Nick

 

[Jim_D]

In my BB 240g I found that the biggest dertritus makers are my snails and urchins, I have my two Tunze 6100's in both back corners aimed towards the front pane, my two low flow areas are roughly underneath the Tunzes and I siphon these areas each week.

 

[VickiG]

... I've been noticing some nuisance hair algae beginning to crop up along my cuttingboard and on my rock work.

Hey, sorry to hitchike on your thread, but Maxx - can I jump in and ask where you got your cuttingboard material? Mike is helping us plan new tank plumbing for our 150 - CL is going to be awesome! We were going with thin substrate, but Mike has given excellent advice and we've decided "bare bottom is where it's at baby"! Not crazy about the see-thru acrylic bottom look, so Mike told me about the cutting board idea and sounds great...now, where to find enough for 5X2 tank? Where did you find yours and how hard was it to cut to fit around OF box etc if you don't mind filling me in. Again, sorry for the hitchike - great thread - I am learning lots about flow! Thanks guys!

 

[Maxx]

www.thecuttingboardcompany.com

Not hard to cut at all. I just used a Jig saw with a normal blade. It was REALLY easy.Get the 1/2" diameter...3/4' will begin to curl at the ends according to some folks.

Nick

 

[tankgirl]

Hi Nick, Mike, Mark,...

My tank's barebottom & I get a fair amount of grit/sand sized detritus, in addition to the usual silt-sized detritus. The tank's 3 years old, and consistently produces about the same amount between siphoning. I assume it's mulm (is that the word?) - bacterial pressure on the rocks causing them to shed.

I just can't figure out how grit or sand size detritus could be removed by circulation alone. I certainly can't get it out that way. Because it forms inside the rock, in all the holes.

I have to use a small powerhead to blow it out of all the holes inside the rocks - then the finer stuff gets circulated in the water column and caught in a micron filter, but the big, coarse stuff I have to blow to one side and then siphon out.

It takes me about a half a day every week to do this - and the time drain (week after week) really gets old. I have all my rocks up on points, so it's fairly easy to blow detritus thru the bottom, once it settles. What takes time is blowing out all the holes inside the rocks, because there's about 400 lbs of it. Then I wait for that to settle or filter out and blow what's left off to one side of the tank, where I can get at it to siphon it out. And, I figure I'm lucky because I have a walk-around tank, so can blow out all the sides of the rock. It seems like it would be almost impossible in a regular tank, to be able to reach the holes in the rocks.

Mike, you've mentioned before that you're able to get the detritus out with current, but I've got around 4000gal/hr circulation and it doesn't even touch the larger and heavier size detritus in my tank, because it can't blow out inside the rocks, where most of it is.

IMO, if you're not getting sand and grit sized stuff out, you're not getting it all out.

Here's a pic of a typical week's worth of siphoning, you can see the size of the stuff;

 

[mojoreef]

TG I get the same stuff. It comes from rock boring critters and sponges working through the rock its self. With the sand/grit thier is not as much of a hurry to get it out, larger chunks of detritus usually get scavenged or broken up, some goes back into the water column some doesnt. I only do my tank once every 3 to 4 weeks for the syphoning. On the rocks I very rarely blow them, instead I use the same syphon and it gets the vast majority.
What i did was to have a hook up that slides over my retur pump (3000 gph). Basically it turn the suction end in the sump into a 3/4 hose with an inline filter (jacuzzi) I just go in suck the stuff off the bottom and then go over the tops of the rocks. The whole proces takes about an hour, three towels and 1 T shirt, lol.


Mike

 

[VickiG]

www.thecuttingboardcompany.com

Not hard to cut at all. I just used a Jig saw with a normal blade. It was REALLY easy.Get the 1/2" diameter...3/4' will begin to curl at the ends according to some folks.

Nick

Thanks Nick! I checked it out...looks like a great way to go. A couple more questions - did you order just the width X length of your tank, or do you recommend getting it a bit bigger and cutting it down? Did you order the sharp or rounded over corners that they offer as a free option? Do you seal it around the edges with silicone to keep detritis from working its way under or ??? Any other likes/dislikes/ideas etc are welcome - this is a brand new concept that Mike just told me about yesterday, so trying to learn all I can. Thanks again!
Vicki

 

[Maxx]

Vicki,
I actually ordered it 1/4 of an inch smaller in width and length than my tank's inner dimensions and i got the rounded edges. I'm almost wishing I had ordered it 1/8 of an inch smaller instead, but that would have been difficult to fit in properly. I did not silicone it in place for a couple of reasons...
I dont like things that are permanantly set in place if I can avoid it, and silicone doesnt stick to HDPP (High Density Poly-Propolene (sp?), basically the cutting board) real well.
I'm always surprised at how people get concerned about the detritus that can collect in the crevice between the glass and the cutting board, when they thought nothing of the same detritus collecting in their substrate...
I just siphon my tank about once a week...blow what ever crap off the rocks I can with a powerhead before hand....this will kick up a bunch of stuff into my water column, so I put a filter sock in my sump to catch as much as possible...let the bigger stuff settle, and then siphon it up. I'm noticing alot less stuff being kicked up by the powerhead as time goes on....in fact, I'm seeing very little these days.....

TG,
I know what you mean about the big stuff not getting picked by the current and taken to the overflow. I just siphon it up....my tank is however, MUCH smaller than yours....
What I saw in the bucket didnt look too bad at all...mostly chunky stuff, little detritus that needed to be siphoned out....

Nick

 

[VickiG]

Vicki,
I did not silicone it in place for a couple of reasons...I dont like things that are permanantly set in place if I can avoid it, and silicone doesnt stick to HDPP (High Density Poly-Propolene (sp?), basically the cutting board) real well....I'm always surprised at how people get concerned about the detritus that can collect in the crevice between the glass and the cutting board, when they thought nothing of the same detritus collecting in their substrate...
Nick

Thanks Nick! Yeah, we felt getting too tight of a fit would be worse than having a small gap. Agree about the 'not wanting permanent' idea too actually. And didn't know silicone doesn't stick to HDPP - thanks for that info! LOL - good point about detritus in crevice vs substrate! One reason to go BB to avoid dirty sand look, constant siphoning (and associated problems with all that of course) but guess you can blow detritus out of crevices or whatever gets stuck, won't be much, so just leave and let coralline cover it up eventually? Am also hoping going BB/cutting board will cut way down on possibility of scratching acrylic by picking up sand in mag cleaner. Still have to be careful of course, but seems like it would be a big help in that respect. So, I take it you are happy with the cutting board concept overall then? I am really doing a 180 from when we decided to get a reef tank after Christmas and I read you must have DSB all the way to BB in 6 weeks of research prior to getting our tank actually planned! But glad I am learning before doing (as much as we can at least) and listening to experience of others! Thanks again! VickiG

P.S. - the cutting board website you gave me mentions using the material for reefs, but I noticed there are no reef links in their link section - how would one suggest having RF staff add a link there? Maybe get some sponsorship ideas going w/the cutting board people if this concept is gaining popularity? Just thinking....always thinking....

 

[tankgirl]

Hi Nick! Good to see you! I'm pretty obsessive about getting that stuff out every week, so I figure that's about what the tank produces in one week. Sigh, yeah, I need a smaller tank that's easier to maintain. That's the best of both worlds.

Hi Mike,
I thought the grit sized stuff was loaded with live and dead bacteria (and hence loaded with phosphates), or at least I read that somewhere? Because of the higher surface area to volume 'thang' - same as with sand? In fact, I thought it was bacterial pressure that caused the grit sized stuff to slough off the rocks.

It just drives me nuts trying to get that stuff out every week and takes me about 3 hours just for that part alone. I keep thinking about downsizing to a nice 90Gal tank because (between daily stuff and weekly stuff) I spend about 14 hrs/week up on a ladder, taking care of the tank. It gets old, even though I love my tank, I'd be a lot happier spending about 4 hrs/week on maint. instead.

Since all that stuff comes mainly out of the insides of the rocks, I haven't been able to figure out a way to get it out that isn't labor/time intensive. Are you sure about it; that the grit sized stuff isn't important to get out? I know you just said so, but I need to know that you're sure about it. Also, a lot of silt sized stuff comes outta the insides of the rocks, too. Confused.

Cute avatar, btw!

 

[mojoreef]

I thought the grit sized stuff was loaded with live and dead bacteria (and hence loaded with phosphates), or at least I read that somewhere? Because of the higher surface area to volume 'thang' - same as with sand? In fact, I thought it was bacterial pressure that caused the grit sized stuff to slough off the rocks.

The rock fragments or snd/grit stuff I am sure has bacteria on and in it, but I dot see that as being a problem or anything to worry about so quickly. If thier is food/waste/detritus tat is a different thing, I suck mine up every 3 to 4 weeks. I believe the sand/rock frags come from boring critters in the rock. The rocks will shed detritus also but it is an organic material and not the sandlike stuff you pictured.

It just drives me nuts trying to get that stuff out every week and takes me about 3 hours just for that part alone.

TG again I wait longer between syphons then you and dont see any negative effects, To confess thier have been times where I left it for a month or so . In my tank I see that most of the material that ends up on the bottom is this sand/rock fragments. I would say 80% of it. the balance is organics that bind to it or get trapped with it.
TG next time you do it put the stuff you have just syphoned out onto a plate and examine it . Get a screw drive and start crushing it, this should give you an idea of how much is hard (which would be rock frags) and how much is soft (organics). The hard stuff does not pose any immediate risk, if the piles of it are allowed to build up then it can start trapping the organics/waste/detritus and will cause a problem. I have a couple rogue rock boring urchins and they ake up more sand/grit in one day then you have in your dish thier.

Mike

 

[tankgirl]

Thanks, Mike!!
I think I'll give it a try; blowing out the rocks less often. And, I'll take a look at the siphon stuff, like you recommended, too. Hah, all my urchin eats is coralline (sigh).

Mike, do you have any pics of your tank, since the re-aquascape? Last pics I saw you were placing the rocks, but I'd love to see it with all the corals back in.

Thanks, again!

 

[Maxx]

Vicki,
I'm liking the cuttingboard. Keep in mind you can do dsb in reef tank...they are not maintenance free like they were advertised, and I dont like how they hamper cleaning or flow rates, but it can be done....

BB lets you jack up the flow, which helps you get the crap outta the tank. Using the cuttingboard is really just to avoid potentially damaging the bottom of a glass tank in the event of a rockslide....for a plexiglass tank, its not going to be an issue. The other unintended benefit to using white cuttingboard is light reflection back up at the corals.....until the corralline algae covers the cuttingboard.

Nick

 

[VickiG]

Thanks for additional info, Nick. Well, I was all over that cutting board idea - - hubby came home and just doesn't like it the way I did. We are getting an acrylic tank, so he says just put something light colored underneath the tank, so you don't look through the bottom and see the stand, and no need for the cutting board since our rocks will be somehow fastened. He thinks it is not necessary and also just will add maitenance issues rather than improve on the BB we are already planning...so...maybe we won't be going that way after all...but I sure did like the idea and sounds like it is working for you. Thanks again for the info.
Vicki