Under gravel filter?

piranhaking · 01/26/2006, 09:37 PM

What are some of the advantages/disadvantages to using ugf's and are they really as bad to cause nitrate issues as many people say?

Fast Fred · 01/26/2006, 09:47 PM

Old technology! Nitrate factory! Not a good idea.

Petstorejunkie · 01/26/2006, 09:51 PM

under gravel filters are great if you use them in reverse. i like to route the return water through them so i never have to vaccum the gravel, it ensures that all yuckies get picked up by the filter.
If under gravel filters are used as origionally intended they can cause huge nitrate issues. i always give people the analogy of a child cleaning their room. you ask a teenager to clean their room, and what do they do, shove it all into the closet. essentially, did the mess really go away, or is it now hidden and harder to get to? this is what an under gravel filter does to all of the fish waste, it puts it in the hardest place to reach in the entire tank!

tntechworker · 01/26/2006, 09:55 PM

wouldnt an rfugf be rather unefficient with a very small grain size of sand? and wouldnt it also prevent the sand from being able to remove nitrate?

Fast Fred · 01/26/2006, 10:05 PM

Sand won't work with a RFUGF unless your use window screen between the two. You sand won't remove nitrate unless it is a Deep Sand Bed of at least 4". It which case any UGF will not allow denitrification, no matter how deep the sand is. Denitrification occurs from Non-aerobic bactreria, meaning no oxygenated water passing through it.

piranhaking · 01/26/2006, 10:08 PM

id like input on this from as many people as i can get even if you agree with what has already been said

Toddrtrex · 01/26/2006, 10:38 PM

Take a look at this thread to see that RFUGF can work quite well.

HTH

Paul B · 01/29/2006, 03:49 PM

That link in the last post is about my tank. UGFs get a bad rap because people try to use them the way we did on fresh water 40 years ago, in salt water you should not use them like that. Mine has been running for 35 years with only one cleaning after 25 years. The difference is that I run it in reverse very slow (150 gal/hr down each tube) and you must put a sponge filter on the intake of the powerheads. There is very little maintenance except that you should stir up the gravel (you can't use sand) a few times a year and suck out the detritus with a canister or diatom filter. You should "powerwash" the rocks in any reef anyway so while you are doing that you can stir the gravel.
If you run it slow you will eventually also have no nitrates.
Good luck.
Paul

01/26/2006, 09:37 PM	#1
piranhaking Registered Member Join Date: Sep 2005 Posts: 321	Under gravel filter? What are some of the advantages/disadvantages to using ugf's and are they really as bad to cause nitrate issues as many people say?

01/26/2006, 09:47 PM	#2
Fast Fred Registered Member Join Date: May 2004 Location: Northfield, NJ 08225 Posts: 1,170	Old technology! Nitrate factory! Not a good idea. __________________ Ya know, for a clown fish, you're not very funny! Member of the New Jersey Reefers Club Current Tank Info: 125g Reef Ready AGA /55g Top Fin Tank for a sump/refugium/ LifeReef Skimmer/ Changing over to SPS only

01/26/2006, 10:05 PM	#5
Fast Fred Registered Member Join Date: May 2004 Location: Northfield, NJ 08225 Posts: 1,170	Sand won't work with a RFUGF unless your use window screen between the two. You sand won't remove nitrate unless it is a Deep Sand Bed of at least 4". It which case any UGF will not allow denitrification, no matter how deep the sand is. Denitrification occurs from Non-aerobic bactreria, meaning no oxygenated water passing through it. __________________ Ya know, for a clown fish, you're not very funny! Member of the New Jersey Reefers Club Current Tank Info: 125g Reef Ready AGA /55g Top Fin Tank for a sump/refugium/ LifeReef Skimmer/ Changing over to SPS only

01/26/2006, 10:38 PM	#7
Toddrtrex Registered Member Join Date: Feb 2004 Location: Carol Stream, IL Posts: 23,162	Take a look at this thread to see that RFUGF can work quite well. HTH __________________ Click my name and then "visit toddrtrex's homepage" for tank pictures Current Tank Info: 210g reef and 65g reef

01/29/2006, 03:49 PM	#8
Paul B Premium Member Join Date: Jun 2002 Location: Long Island NY Posts: 15,549	That link in the last post is about my tank. UGFs get a bad rap because people try to use them the way we did on fresh water 40 years ago, in salt water you should not use them like that. Mine has been running for 35 years with only one cleaning after 25 years. The difference is that I run it in reverse very slow (150 gal/hr down each tube) and you must put a sponge filter on the intake of the powerheads. There is very little maintenance except that you should stir up the gravel (you can't use sand) a few times a year and suck out the detritus with a canister or diatom filter. You should "powerwash" the rocks in any reef anyway so while you are doing that you can stir the gravel. If you run it slow you will eventually also have no nitrates. Good luck. Paul __________________ I used to get shocked when I put my hand in my tank. Then the electric eel went dead. Current Tank Info: 100 gal reef set up in 1971

01/26/2006, 09:51 PM	#3
Petstorejunkie Registered Member Join Date: Dec 2005 Location: Atlanta, GA Posts: 350	under gravel filters are great if you use them in reverse. i like to route the return water through them so i never have to vaccum the gravel, it ensures that all yuckies get picked up by the filter. If under gravel filters are used as origionally intended they can cause huge nitrate issues. i always give people the analogy of a child cleaning their room. you ask a teenager to clean their room, and what do they do, shove it all into the closet. essentially, did the mess really go away, or is it now hidden and harder to get to? this is what an under gravel filter does to all of the fish waste, it puts it in the hardest place to reach in the entire tank!

01/26/2006, 09:55 PM	#4
tntechworker Registered Member Join Date: Jan 2006 Posts: 8	wouldnt an rfugf be rather unefficient with a very small grain size of sand? and wouldnt it also prevent the sand from being able to remove nitrate?

01/26/2006, 10:08 PM	#6
piranhaking Registered Member Join Date: Sep 2005 Posts: 321	id like input on this from as many people as i can get even if you agree with what has already been said