overdoing filtration?

[pinantanjohn]

Looking at the research material and reading the posts here I'm curious as to whether, by using a large fractionator (4" dia 36" high) as well as a fuge with good macros and other plants, plants in the tank as well as a 4 to 5 inch sand bed, if i can get away with less than 1.5 lb/gal of live rock? I understand that amount would be better, but I'm planning a fairly light fish load (8 or 10 chromies and a goby) in a 75 gal tank with about 25 gallons in the sump/fractionator. I expect that I could without problems. Most of the stuff I've been reading is very subjective as to the "way" things are done. I guess my real question would be if the rock would be actually benificial in a small quantity, like 20 or 30 pounds total? Would the "good stuff" spread and grow on other rock over time, and roughly how fast would the bac spread? (that sounds like a really stupid question)

Also, would it be possible to use only a small quantity of live sand to seed a good sized sandbed? If all that is needed to get the bac to spread is substrate and food I don't see why that woulden't work. I have much more time than money and I'm not objective to spending a year getting the tank ready. Is that a reasonable tradeoff?


The thing is i have little money for a while yet ( a year or so) but I have the tank and pumps, (believe it or not I found them at the dump, A complete system for fresh basically brand new) and access to materials to build the rest of the stuff. The price of LR and LS up here is prohibitive and i have to transport it about 4.5 hours from Burnaby, BC. That's the closest real salt LFS around. The local places are only petsmart and petland. They have some salt stuff, chems, fish and such but no rock or sand.

Does this sound like a stupid question? Its 2:00 am and i'm not thinking that clearly..

[jnohs]

n o matter what it will take it will take a year to get any tank running smothly. regardless of the method of setup. trhere is a constant war between all the microfauna in well established tank. and those wars take time and there are many of them. for instance star fish have seemef to really take hold of my substrate lately but i figure something will soon take over them then somthing else.....

[Octoman]

Pinantanjohn, all of the "rules" we follow are really just subjective guidelines. It's a good idea to have more rock, but each system is different. Any amount of rock provides more beneficial surface area for biological filtration. But having less rock limits the bioload you can put on the tank and limits the "safety factor" that protects you from a crash when something dies/decays in the tank.

It would be impossible to say if you have "enough" rock. There are too many other factors to consider like quality of the rock, how often you change water, bioload, other filtration methods, etc... More porous rock has greater surface area, you can do more frequent water changes to export more dissolved waste/nutrients. The most important thing with any system is to test frequently, always know what your water parameters are.

As far as the nitrifying bacteria go, they will be able to colonize rather quickly (~month). However, like Jnohs was saying, it can take up to a year before things (much more than just ammonia and nitrite) stabilize, and even then changes such as new rock, rearranging old rock, adding new fish/corals, etc... will upset the whole system again. Also, denitrifying bacteria (the ones that get rid of nitrate) can take much longer than a month to colonize.

IMO, the biggest advantage of true live sand is the meiofauna that comes with it. These are the worms, pods, and other tiny critters that are extremely important to a healthy sandbed. These don't come in the "live sand" that sits on the shelf at the LFS, but you could get some from a local reefer to seed your sand bed. The stuff on the shelf (such as aragalive) only has bacteria spores in it and IMO is not worth the $ because these spores and bacteria will be plentiful on your live rock and can seed the sand bed from there.

[pinantanjohn]

That's about what I figured.. Thanks. I do expect it to take a long time for the system to stabilize. I'll have to find somone close to Kamloops sometime in the fall.

Peace...
John

[Woodstock]

Yes, you can safely substitute a sand bed for rock. You do not need 1.5-2# of live rock per gallon of water if you have a sand bed.
The sand grains provide an enormous amount of surface area for the nitrifying bacteria to live on and if deep enough (2-3" fine sand), it will also provide denitrifying capabilities.
In my 120 gal reef (w/30 gal sump) I probably only have 100# or less of rock but my sand bed is 2-3". It is a very stable system.
Just add your bioload slowly and don't forget to QUARANTINE everything 'wet' for at least 4 weeks before placing it in your display!

[pinantanjohn]

Thanks Woodstock... (that used to be my nick... The bird not the event)

I do intend to have no less than 4 inches of sand, but i didn't want just sand. I also don't have a very wide tank. it measures 12X48X22 high so having the recommended amount of rock dosen't leave much sand area left. There's a photo on the site of a tank that is decorated like a roman ruin and that's been my inspiration.

With roughly 80% of the bottom in sand, 10% rock and 10% eyecandy along with plants, a REALLY big fractionator (4X36) and a bio filter sump/fuge I'm not expecting too much trouble as far as stability. I've had fresh for years and have not lost many fish. I have a goldfish I've had from the last tank I've cycled (I bought a feeder to get things started) and he's now about 6 inches long. Just getting to the point where I'm going to have to get him out of the 25 gal tank before he has too many problems. He's just too big and he trashes anything I put in there. Haven't had plants for a year and he's eaten about 40 livebearers and all my snails. Lil' bugger, but I can't bring myself to actually make him go away...

Call me sentimental...

If you have some idea, with the 4" sand bed and, if I can find some, a couple of cups of good old live sand from an established tank, what would you say would be a general timeframe for reasonable population in the sandbed? 9 months? I know it's going to depend on many things not the least of which is feeding it, but would that be reasonable or am I too optomistic?

Thanks again...

Peace...
John