Filtration in a fish only tank

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piratesattack

Aquarium Advice Newbie
Joined
Nov 2, 2003
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Seattle
At some point in the future I will be setting up a large fish-only tank (between 100-150 gal). I know that I can either use a wet/dry system or live rock w/ a skimmer to filter the tank. Which set-up will insure the healtiest fish? This tank is going to be used in a controlled experiment and maintaining healthy livestock is paramount. I understand that there may be strong personal opinions as to which one is "better" and accordingly I would prefer advice based on experience with both systems or other evidence-based reasoning rather than hearsay.

Thanks in advance.
 
Either will give you efficient biological filtration. The wet/dry system has no means to control nitrate though. Your nitrates will rise with that system unless you have another way to export them such as frequent water changes. LR, on the other hand, will give you some nitrate reduction due to the anoxic areas inside the rock. Of course it won't have the effect of a DSB, and since you didn't mention that, I'm assuming it's not an option. The LR will also give you a greater biodiversity in the tank which I think makes for a better environment...depending I suppose on what grows on your LR. Most of us like the large populations of pods, worms, ect... but might hesitate at a nice big patch of aiptasia. I would suggest a skimmer either way as it will remove stuff that would otherwise decompose and be converted to nitrates. Lower nitrates = healthier fish. IMO & IME, the closer you can mimic nature, the better off you and your fish are.
 
I agree with above. Just because you are going with a FO tank doesn't really change the rules. A 100-150 lbs of LR plus a good skimmer will make life a lot easier on your fish and render a wet/dry moot unless you intend on seriously over-stocking. I'd also advise some type of sump on a 150gal simply because it makes maintenence and skimming a lot more efficient and centralized. The biggest problem I've encountered with large tanks is not enough circulation, but efficient circulation. Plan your plumbing and filtration using common sense. Such as, water being removed form the tank on one end, and being returned on the other, and top-down water circulation vs horizontal firing power-heads. On a 20, 30, or even 55gal, this isn't as big a problem. When you start getting up to 150gal you need to think things through.

On the other hand, if you don't have the option of using a lot of LR (cost, size, short term set-up, politics, etc) you'll need some help with the nitrogen cycle. In that case, I still say 'bah-humbug' to wet/drys because those good old Emperor filters with the bio-wheels do the same darn thing in a lot smaller package with less screwin' around. You can then pull the wheels off at a later date if you decide to add LR to the tank.

If the tank is going to be heavily stocked, a large cannister filter with AC would certainly help since without the typical assortment of filter feeders and invertebrates running around you'll have more suspended organics in the water too big for the skimmer and too small for the fish tp grab.
 
Thanks for the advice!

I had in mind that there would be a sand bed, but I don't think we could have one of sufficient depth to truly get the proper effects.

It was interesting that politics was mentioned in regards to the live rock. Ideally, we would like to avoid wild rock, but I was under the impression that was the only feasible option. Is there an easy way to to acquire cultivated live rock?
 
You can order aquacultured LR from Florida. I believe one of our sponsors here offers it. www.liverocks.com You can make your own rock using aragonite gravel and white portland cement. See www.garf.org for directions on making "aragocrete".
In order to get nitrate control, you'll need a sandbed at least 4" deep. You can go up to 6", but you need at least 4" and the sand needs to be sugar sized aragonite if possible.
 
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