Question about FO (fish only) tank

warrenmichaels · 01/09/2019, 12:44 AM

I just read that it's possible to have a FO tank without live rock. Is all that is needed in this setup just a powerhead to circulate water, a heater, and water changes?

If so, what really needs to be done concerning water parameters? Is it really so simple that you just have to mix up salt, without having to worry about Alk, Mg, pH, and Ca levels if sufficient water changes are done?

mcgyvr · 01/09/2019, 05:39 AM

I "think" you mean that you can just use dry rock vs buying the more expensive dry rock? Is that true? If so absolutely yes..
If you mean no rock at all...well.. that answer is likely no long term without some other way to increase the surface area in an aquarium..

Rock in a tank provides extensive surface area for bacteria as well as low oxygen areas deeper in the rock for other different bacteria.. The bacteria is what does most of the work in a tank as far as the nitrogen cycle is concerned (toxic ammonia converted to lesser toxic forms)
Without some other method to drastically increase surface area a tank alone lacks sufficient surface area to sustain a sufficient bacterial population long term..

One can setup a temporary tank (for qt or other purposes) and constantly maintain the water quality via water changes but thats not really sustainable long term or with a large/normal tank bioload.

"live rock" simply means that there is bacteria living on it.. Dry rock quickly becomes "live" rock once placed into water.

marzvt · 01/09/2019, 08:19 AM

there is a problem with an empty tank. There is an old adage, "the more places you give your fish to hide the more you see them". Fish need places to hide to feel comfortable, if not they remain stressed and are prone to sickness. It will also make it impossible to manage aggression as well if you don't give the weaker fish an out.

Just for the theory sake. So you want s cube of glass with no rock visible? You would be amazed at how quickly the parameters go off if the tank isn't cycled with rock. I struggle with it on my hospital tank and I end up doing a 50% a day water change to keep up. With that being said the rock or media doesn't need to be visible. Many of us have extra rock or marine pure in our sumps to augment what is in the tank. I would just load up your sump with marine pure if that is what you are interested in. But this doesn't solve the problem I stated above, these are living animals with needs and fears, not art.

ChronicReefH2o · 01/09/2019, 12:00 PM

Can you keep fish without live rocks? Yes.
Would I do this? No.

Reason is because the live rocks help with cultivating beneficial bacteria in turns help with nutritions and phosphate break down. The rocks provide the breeding ground for the bacterial, hiding places for the fish, and areas where fish can sleep at night.

warrenmichaels · 01/09/2019, 05:42 PM

The post was initially made in regards to a fish only tank, but issues related to QT tanks were also mentioned. I'd always have some sort of cover for a fish. The question was in relation to chemical parameters of the water.

So, if appropriate rock (or Matrix, or whatever) is used, what parameters need to be addressed, all the usual that would be checked for a reef tank, or just salinity, and temperature?

Regarding the QT, when you had to do 50% daily changes, was this with a sponge? How did you know you had to change the water, did an ammonia badge go off?

tjm9331 · 01/09/2019, 07:54 PM

Temp, salinity, ph (more or less, there are some environmental factors that can affect ph) and nitrates is all I’d be concerned about when it comes to a fish only tank.

That said I agree with everyone here about surface area but live rock or rock in general is not the only way to get surface area.

If you run a sump you can use “bio-balls” for surface area although not recommended as they tend to be nitrate factories. If I was going to go FO and wanted some other decorations in the display tank other than rock then I’d setup a sump and use marine pure blocks/balls for surface area.

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OldReefGuy · 01/09/2019, 09:03 PM

OP, IMO, yes. You can do this. Keep up with water changes (only to keep Nitrates and fish poop in check). However, that will become bothersome after several weeks, and you will end up with a wet&dry/HOB or Canister filter. So I would invest in a good wet/dry system or a good canister now. My fav is the Hydor Pro, however, lots around, even some good chinese ebay. heck, if you lived in LA, I would even just give you one. Also, check criagslist.....

Bring on the Nitrate Factory flamers!!!!

warrenmichaels · 01/09/2019, 11:02 PM

Good info, thanks to everyone!

warrenmichaels · 01/10/2019, 12:03 AM

Quote:

Originally Posted by OldReefGuy

OP, IMO, yes. You can do this. Keep up with water changes (only to keep Nitrates and fish poop in check). However, that will become bothersome after several weeks, and you will end up with a wet&dry/HOB or Canister filter. So I would invest in a good wet/dry system or a good canister now. My fav is the Hydor Pro, however, lots around, even some good chinese ebay. heck, if you lived in LA, I would even just give you one. Also, check criagslist.....

Bring on the Nitrate Factory flamers!!!!

Good info from everyone, thanks.

I have a fluval internal canister filter that I was thinking of using for a QT, but I'd rather not ruin it in salt. Think it would be OK?

OldReefGuy · 01/10/2019, 12:26 AM

what do you mean ruin it in salt? That Fluval is a good unit. You should have zero issues.

OldReefGuy · 01/10/2019, 12:30 AM

How big off a tank is this? Cause the internal ones are usually for smaller tanks.

warrenmichaels · 01/10/2019, 10:10 AM

Quote:

Originally Posted by OldReefGuy

How big off a tank is this? Cause the internal ones are usually for smaller tanks.

20 Gal QT. This has nothing to do with setting up a FO tank.

tjm9331 · 01/10/2019, 10:33 AM

Quote:

Originally Posted by warrenmichaels

20 Gal QT. This has nothing to do with setting up a FO tank.

You can absolutely get away with the internal filter on the 20 gal. The old guy was under the impression you were asking if the internal filter would be ok to use on the display tank, as was I

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OldReefGuy · 01/10/2019, 11:06 AM

^+1

warrenmichaels · 01/10/2019, 12:07 PM

OK, thanks.

warrenmichaels · 01/10/2019, 02:01 PM

One more thing, would dosing to keep Ca and Alk up in either a fish only tank or a QT be necessary?

tjm9331 · 01/10/2019, 03:14 PM

Quote:

Originally Posted by warrenmichaels

One more thing, would dosing to keep Ca and Alk up in either a fish only tank or a QT be necessary?

absolutely not, Ca and Alk are for corals, no need to worry about them in a FO display tank and definitely not a QT

warrenmichaels · 01/10/2019, 03:23 PM

Quote:

Originally Posted by tjm9331

absolutely not, Ca and Alk are for corals, no need to worry about them in a FO display tank and definitely not a QT

good to hear, thanks. Out of curiosity, before the days of adding kalkwasser to ATOs, how did people regulate Ca and Alk in a reef tank? Was a little bit of supplement added once per day?

tjm9331 · 01/10/2019, 09:36 PM

Quote:

Originally Posted by warrenmichaels

good to hear, thanks. Out of curiosity, before the days of adding kalkwasser to ATOs, how did people regulate Ca and Alk in a reef tank? Was a little bit of supplement added once per day?

Honestly I have no idea, I’m new to dosing myself.

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OldReefGuy · 01/10/2019, 09:41 PM

Yes...a little a day

warrenmichaels · 01/11/2019, 11:35 AM

I think that does it. Thanks for all the replies.

01/09/2019, 12:44 AM	#1
warrenmichaels Registered Member Join Date: Nov 2014 Posts: 63	Question about FO (fish only) tank I just read that it's possible to have a FO tank without live rock. Is all that is needed in this setup just a powerhead to circulate water, a heater, and water changes? If so, what really needs to be done concerning water parameters? Is it really so simple that you just have to mix up salt, without having to worry about Alk, Mg, pH, and Ca levels if sufficient water changes are done?

01/09/2019, 05:39 AM	#2
mcgyvr Registered Member Join Date: Sep 2003 Location: North Carolina Posts: 20,050	I "think" you mean that you can just use dry rock vs buying the more expensive dry rock? Is that true? If so absolutely yes.. If you mean no rock at all...well.. that answer is likely no long term without some other way to increase the surface area in an aquarium.. Rock in a tank provides extensive surface area for bacteria as well as low oxygen areas deeper in the rock for other different bacteria.. The bacteria is what does most of the work in a tank as far as the nitrogen cycle is concerned (toxic ammonia converted to lesser toxic forms) Without some other method to drastically increase surface area a tank alone lacks sufficient surface area to sustain a sufficient bacterial population long term.. One can setup a temporary tank (for qt or other purposes) and constantly maintain the water quality via water changes but thats not really sustainable long term or with a large/normal tank bioload. "live rock" simply means that there is bacteria living on it.. Dry rock quickly becomes "live" rock once placed into water. __________________ Who me?

01/10/2019, 02:01 PM	#16
warrenmichaels Registered Member Join Date: Nov 2014 Posts: 63	One more thing, would dosing to keep Ca and Alk up in either a fish only tank or a QT be necessary? Last edited by warrenmichaels; 01/10/2019 at 02:07 PM.

01/09/2019, 08:19 AM	#3
marzvt Registered Member Join Date: Nov 2017 Location: Vermont Posts: 52	there is a problem with an empty tank. There is an old adage, "the more places you give your fish to hide the more you see them". Fish need places to hide to feel comfortable, if not they remain stressed and are prone to sickness. It will also make it impossible to manage aggression as well if you don't give the weaker fish an out. Just for the theory sake. So you want s cube of glass with no rock visible? You would be amazed at how quickly the parameters go off if the tank isn't cycled with rock. I struggle with it on my hospital tank and I end up doing a 50% a day water change to keep up. With that being said the rock or media doesn't need to be visible. Many of us have extra rock or marine pure in our sumps to augment what is in the tank. I would just load up your sump with marine pure if that is what you are interested in. But this doesn't solve the problem I stated above, these are living animals with needs and fears, not art.

01/09/2019, 12:00 PM	#4
ChronicReefH2o Registered Member Join Date: Jan 2019 Location: South SoCal Posts: 61	Can you keep fish without live rocks? Yes. Would I do this? No. Reason is because the live rocks help with cultivating beneficial bacteria in turns help with nutritions and phosphate break down. The rocks provide the breeding ground for the bacterial, hiding places for the fish, and areas where fish can sleep at night.

01/09/2019, 05:42 PM	#5
warrenmichaels Registered Member Join Date: Nov 2014 Posts: 63	The post was initially made in regards to a fish only tank, but issues related to QT tanks were also mentioned. I'd always have some sort of cover for a fish. The question was in relation to chemical parameters of the water. So, if appropriate rock (or Matrix, or whatever) is used, what parameters need to be addressed, all the usual that would be checked for a reef tank, or just salinity, and temperature? Regarding the QT, when you had to do 50% daily changes, was this with a sponge? How did you know you had to change the water, did an ammonia badge go off?

01/09/2019, 07:54 PM	#6
tjm9331 Registered Member Join Date: Jun 2016 Location: Massachusetts Posts: 340	Temp, salinity, ph (more or less, there are some environmental factors that can affect ph) and nitrates is all I’d be concerned about when it comes to a fish only tank. That said I agree with everyone here about surface area but live rock or rock in general is not the only way to get surface area. If you run a sump you can use “bio-balls” for surface area although not recommended as they tend to be nitrate factories. If I was going to go FO and wanted some other decorations in the display tank other than rock then I’d setup a sump and use marine pure blocks/balls for surface area. Sent from my iPhone using Tapatalk

01/09/2019, 09:03 PM	#7
OldReefGuy Registered Member Join Date: Dec 2004 Location: Granada Hills Posts: 542	OP, IMO, yes. You can do this. Keep up with water changes (only to keep Nitrates and fish poop in check). However, that will become bothersome after several weeks, and you will end up with a wet&dry/HOB or Canister filter. So I would invest in a good wet/dry system or a good canister now. My fav is the Hydor Pro, however, lots around, even some good chinese ebay. heck, if you lived in LA, I would even just give you one. Also, check criagslist..... Bring on the Nitrate Factory flamers!!!!

01/09/2019, 11:02 PM	#8
warrenmichaels Registered Member Join Date: Nov 2014 Posts: 63	Good info, thanks to everyone!

01/10/2019, 12:26 AM	#10
OldReefGuy Registered Member Join Date: Dec 2004 Location: Granada Hills Posts: 542	what do you mean ruin it in salt? That Fluval is a good unit. You should have zero issues.

01/10/2019, 12:30 AM	#11
OldReefGuy Registered Member Join Date: Dec 2004 Location: Granada Hills Posts: 542	How big off a tank is this? Cause the internal ones are usually for smaller tanks.

01/10/2019, 11:06 AM	#14
OldReefGuy Registered Member Join Date: Dec 2004 Location: Granada Hills Posts: 542	^+1

01/10/2019, 12:07 PM	#15
warrenmichaels Registered Member Join Date: Nov 2014 Posts: 63	OK, thanks.

01/10/2019, 09:41 PM	#20
OldReefGuy Registered Member Join Date: Dec 2004 Location: Granada Hills Posts: 542	Yes...a little a day

01/11/2019, 11:35 AM	#21
warrenmichaels Registered Member Join Date: Nov 2014 Posts: 63	I think that does it. Thanks for all the replies.