Do I have enough filtration?

[azreefer]

Hi all!,

I recently purchased a 240 gallon acrylic tank ( 96" x 24" x 24" ) and want to set it up as a fish only tank since I don't have the funds to support another reef tank. The tank is drilled on the bottom and has 4 intake bulkheads and two returns. The intakes and returns are evenly spaced across the bottom of the tank. The intakes have grates and screen over them and the returns have flexible tubing on them so they stick out above a 4"-5" layer of crushed coral. There are two Little Giant 4MDQ-SC pumps running this system for a total flow rate of 1620 gph. Each of these pumps has a PEP canister filter in line that has a filter membrane in it. I am going to add a large skimmer to the tank also.

Do you think this large undergravel filter will support the tank if there is a fairly light bio load. I was thinking of getting a single banded cat shark and a spotted ray. I realize that most people are setting up these types of tanks with a wet-dry but I'm trying to save a few bucks. Anyone have any suggestions?

 

[caecosystems]

You will need a sump to run a protien skimmer on the tank. Undergravel is not very exciting but if that is all you put in it, should not be a big deal. Good luck.

 

[esmithiii]

undergravel filters are a timebomb waiting to happen. Do some research before you have to tear everything down to set it up right.

Ernie

 

[caecosystems]

Not a time bomb if you gravel vac it regularly. ie twice a month.

 

[esmithiii]

caecosystems-How do you clean the detritus under the filter? Also, how do you gravel vac under liverock?

There are many very good reasons why almost no knowledgeable reefkeeper uses undergravel filters anymore. DSBs and liverock as primary filtration eliminate so many problems. My recommendation is to start right from the beginning. I had an undergravel filter when I bought my first SW tank (bought it used) and six months later I couldn't keep the algae in check even when I was cleaning the gravel weekly! That and I had a relatively low bio load.

IMO there is no reason to do an Undergravel filter. A 6" sand bed alone provides more bio filtration, IMO.

Just my opinion.

 

[Anonymous]

Even in a FO tank they collect and store too much crap. Plus, why would you want to do more work?(cleaning twice a month and syphoning the gravel). It would be better to add a DSB and some good skimming. More practical IMO.

 

[ChrisRD]

Do you think this large undergravel filter will support the tank if there is a fairly light bio load.

IMO it would work, but I'm with Ernie on this one - no way would I ever setup another undergravel filter. IME of all the filtration options you have, a traditional-flow (as opposed to reverse-flow) undergravel filter is the worst choice. JMO.

 

[Reef Guy11]

I am diffently with Erine and everyone else Undergravel is not the way to go using a sump and a good protein Skimmer is the best way to go. It takes out the majority of clean the tank and you also have the time to enjoy your tank instead of working on it and being inside it all the time. Also use a Close Loop for Circulation better than Power heads.

 

[azreefer]

Thanks for the advice. I would have never considered it but the tank was set up like this already. I don't have any experience with an undergravel filter so I wasn't sure how much work it would be to clean. I just figured that 250lbs of crushed coral would provide plenty of bio material. I think I'll just build a sump and set up a closed loop system. That's how my 40 gal reef is set up and it's doing awesome. I've had 18 coral frags in it for almost a year now and every piece is growing like crazy. I have to frag them quite a bit to keep everything under control.

Thanks!

 

[esmithiii]

AZ- the thing about crushed coral is that it is a detritus trap. The detritus falls in between the pieces of crushed corals and rots. In a sand bed, there is the proper kind of life to process all the waste. Lower layers process wastes anerobically and convert nitrates into hydrogen sulfide gas which escapes into the air. Keep in mind also that the surface area of sand is much higher than crished coral.

Can you post a photo of the tank and its plumbing? Maybe the existing plumbing could be leveraged when incorporating a closed loop.

Ernie

 

[Garry thomas]

hello again not to push to finer point! But when nitrates are converted and bubbled off into a harmless gas it is nitrogen not hydrogen! there is a differance..GT s.wales

 

[caecosystems]

Anoxic bacteria (bacteria that utilize oxygen but live in a low or no oxygen environment) Take the oxygen off of the nitrate (NO3) leaving Nitrogen gas. Clear bubbles in your sand bed (against the glass) is Nitrogen as oppossed to black bubbles....being hydrogen sulfide.