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View Full Version : big tank = less water changes?



dexxl
Fri Jan 09, 2009, 12:54 PM
Hi all,

i'm new to the forum and in comparison with most of you, i'm still green at fish keeping. I've read up and learnt from alot of the post in this forum and also on the internet. in my ignorance, i still don't see how it's sooo difficult to keep fish, so i went out and bought myself some discus :)

the biggest grip i see with discus keeping is the strict cleaniness regime that has to be kept in terms of water quality. My question is that, is that in relation to the actual size of the tank?

as in, if lets say i have a 200 litre tank and i need to do water changes once every 3 days. if i had a 1Kl tank, could i do the water changes once every fortnight? since ammonia and nitrogen/nitrites are non biological. shouldn't the density of contamination of residue be diluted with the a larger volume of water with the same population?

yes, i'm asking cos i'm lazy and will only do it if i haaavvveeeee to :?

once the discus i purchase start gaining some size and maybe pair off, i'm thinking of building a huuge tank. out of plywood with some kind of olefin lining. I'll assemble suction and discharge manifolds so water changes would be extremely simple. when i do get to that stage, hopefully i'll remember to post as well. (if it works of course) :lol:

stormhenge
Fri Jan 09, 2009, 03:31 PM
most people go for the bigger tank in order to keep more fish, because a 90 gallon tank with the population of a 50 gallon tank would look rather barren.

but if you were to keep a smaller population, but use the filtration required for the larger volume of water i would have to guess that you would have almost no troubles with your water quality.

however, it is also suggested that you do regular water changes in order to replaced the mineral content in the water, which is what i do because my tank never has a reading higher than 0 of ammonia, nitrite, or nitrate, but thats because i have the filtration of a 50 gallon tank on my 30 gallon tank.

hope that helped.

ILLUSN
Fri Jan 09, 2009, 09:21 PM
if you feel like being lazy why dont you concider angels instead of discus? with 9 adults in a 6x2x2 planted i had problems when i stepped back my water changes from 50% twice a week to 30% twice a week, the fish looked lethargic but always picked up after a water change. ammonia was 0 nitrite was 0 nitrate was below 10 always. filtration was an eheim 2080, 2217 and a fluid bed filter.

water quality is paramount with discus it keeps them well and its not just the nitrogenous waste you have to worry about, disolved organics and other wastes also play their part.

1fish2fish3fish
Mon Jan 12, 2009, 03:03 AM
yes, i'm asking cos i'm lazy and will only do it if i haaavvveeeee to

If this is how you feel now, maybe discus is not the fish for you..

dexxl
Mon Jan 12, 2009, 03:47 AM
why would i want to work harder then i have to for the same result? why would anyone?
I do understand that water changes are necessary for dilution/removal of ammonia when it reaches saturation point. but i don't understand the act of continuous frequent water changes having any positive impact on the health of the fish. my theory is that if you do have a big tank with a much larger volumetric capacity of water, it should take much longer for ammonia to reach saturation for the same population then it would in a small tank.

so,.. if my theory is wrong, someone please tell me why. but telling me that 'it's just something i have to do' or to get new fish, isn't really convincing me of anything. also i doubt that i'll be able to get my hands on any barrier that would be able to filter out ammonia. and i really don't want to invest in filtrations in the micro or ultra levels at this time...

hhmmm,.. can ammonia be biologically filtered?

dexxl
Mon Jan 12, 2009, 03:56 AM
ehh actually, i don't want to invest in micro or ultra filtration at all... it'd just be waaayyyy too expensive. and since i don't have the license to build a pressure vessel i guess it's not an option..

anyone ever tried to control ammonia chemically? i'm thinking with citric or ferric acid. it should help with a small level of disinfection at the same time,.. no?

ILLUSN
Mon Jan 12, 2009, 04:11 AM
Sorry but your thinking is wrong.
water changes are not done to dilute ammonia, biological filtration converts ammonia into nitrite then nitrate, ammonia MUST always be 0, Nitrites MUST always be 0, nitrates are ok but my fish always do better when they are low, in rivers nitrates are ALWAYS 0 so its best to try and keep it that way in an aquarium. fish produce other waste then just ammonia they also produce solid waste that breaks down into other substances that cant be tested for. The igest vale of water changes it that it removes nitrate and all these other "organics". you can filter chemicly with bio chem zob, chemi pure purigen zeolite, carbon etc, but again you have the same problem as you never really know whats being removed (trace elemants as well as waste) and what isn't.

BigDaddyAdo
Mon Jan 12, 2009, 07:34 AM
If you have yet to understand the reasons behind running a filter then i would recommend that you do a whole lot more research before you even consider buying a discus.

Just google cycling your aquarium.


Ado

dexxl
Mon Jan 12, 2009, 12:04 PM
did you actually read the thread before replying?


If you have yet to understand the reasons behind running a filter then i would recommend that you do a whole lot more research before you even consider buying a discus.

Just google cycling your aquarium.


Ado

dexxl
Mon Jan 12, 2009, 12:14 PM
in your experience, how long does it take from 'fish produced waste' to dangerous levels of toxins in the water from a fresh source? for the sake of estimation, lets assume all controlled factors and with adequate amounts of filtration.


Sorry but your thinking is wrong.
water changes are not done to dilute ammonia, biological filtration converts ammonia into nitrite then nitrate, ammonia MUST always be 0, Nitrites MUST always be 0, nitrates are ok but my fish always do better when they are low, in rivers nitrates are ALWAYS 0 so its best to try and keep it that way in an aquarium. fish produce other waste then just ammonia they also produce solid waste that breaks down into other substances that cant be tested for. The igest vale of water changes it that it removes nitrate and all these other "organics". you can filter chemicly with bio chem zob, chemi pure purigen zeolite, carbon etc, but again you have the same problem as you never really know whats being removed (trace elemants as well as waste) and what isn't.

Hollowman
Mon Jan 12, 2009, 06:59 PM
Like the other guys, I would say that you need to do some considerable reading up on the Nitrogen Cycle. You obviously do not understand this or the need for discus or any fish to live in optimum condition for them to thrive.
Yes, discus will live in poor conditions, and if thats what you are going to think of doing by not changing water, it seems that they are destined for a shorter and unhappy life. But that is just lazyness.

As has been described by ILLUSN, or did you just ignore his post, he has explained about what we call DOC's or Dissolved Organic Compounds. He said that the fish produce waste, not just poo, but organics that cannot be tested for easily. These include toxic phenols and hormones and a number of other things. These will build up in a stocked tank from the momnet after you have changed the water.
Ask a breeder how often he/she changes water on his tanks, the answer you will get will be between 100 and 300% A DAY. Why is this?? He/she wants to keep the water free from organics as well as the build up of ammonia and nitrIte.
A hobbyiest will generally change 33% of their water in a stocked tank 3 times a week. If this is too much, maybe re-think keeping discus.

You must remember that many of the members here have been keeping discus and other fish for many years. The wealth of experience here is freely given to those who want to listen. Do you think that if there was an easy way to raise discus we would not tell you? It is what it is, to keep these fish in good health, you need to learn about good water, no more, no less.

Hollowman

rex82
Mon Jan 12, 2009, 09:22 PM
I think dexxl isn't trying to say that he aint going to do water changes at all. he's trying to say that he wants to understock a fish tank to the point where water quality will stay better for longer. he will still need to do them though how much and how often will be determined by his stocking levels, feeding regime, etc.
Mate if you are that lazy...... just put your tank on a constant drip system if you have plenty of water and parameters allow

Hollowman
Mon Jan 12, 2009, 09:29 PM
Rex, I understand what you say. But on the flipside, without enough of a bioload, your filter will crash, there has to be enough waste to keep it going.
Why have a huge tank and understock? seems like a waste of time to me. :?

ILLUSN
Mon Jan 12, 2009, 11:44 PM
in your experience, how long does it take from 'fish produced waste' to dangerous levels of toxins in the water from a fresh source? for the sake of estimation, lets assume all controlled factors and with adequate amounts of filtration.

I'll be honest and tell you it depends on bioload, dad's old tank was a 160L 4x14x18 this tank wasn't big, he used 2 eheim 2217's on this tank one with bio chemzorb the other with bio media, he did water changes weekly of about 50%, between changes his NO3 would peak at about 50-60ppm, in this tank he housed 8 discus between 3 inches and 6.5 inches, fish lived long enough (6+ years) but always had some fin rot and the fish were always smaller than in mine.

my tank 4x2x2 430L housed 8 fish filtered by an eheim 2028 (bio media only) and a fluid bed filter bare bottom these fish got 40-50% changes every 2 days, in 6 moths 2 inch fish were bushing 5.5 inched after 2 years i have some 7.5 inch monster fish (minus tail :) )

generally as holloman has has described the moment you add fish water quality declines, as for how long it takes, my advice is to get yourself a good no3 test kit and measure that once it hits about 20ppm you know your over due for a change, so do a big change, my guess is with a nice 1000L bare bottom tank with say 10 adult discus you'll be changing 30% of your water every 3-4 days to keep your NO3 in check and cleaning your filters every 1-2 months.

pink66
Tue Jan 13, 2009, 12:31 AM
mmm.. I understand this all way too well.. When I first started out in Discus, I decided on a 5x2x2 tank and was only going to have 5 fish.. This way I could maintain everything well and in balance - good water quality and minimal WC's.. as my work keeps me very busy indeed. I did not want to always be changing water.. my how the reality of the situation bites you on the bum :shock:

Firstly, I now have 10 (damn, they are so hard to say no to :oops: .. soo cute - i have to stop adopting them - tanks full but dont worry, i am setting up a new one in the office :roll: )

Secondly, Jothy you mention that it is not just levels of ph,no2,no3, etc, but infact is the amount of WC changes that make the fish really happy.. I now see that to be true.

I was trying to stretch out the WC to assist with water restrictions until I can get an alternative source sorted.. The parameters were holding fine, but waiting longer was causing the fishies to be much more lethagic and disinterested in their environment.. so I am just going to have to be smelly and cut down on showers :wink: as my fish need more frequent changes.. they are happy with a 50% change every 3-4 days, swimming around madly eating their own body weights in food each day :), growing really fast and investigating their surrounds all day long.. (and i continually monitor parameters)

Even after keeping fish for 25 years, I thought I had it all pretty organised. it is only since I have taken on Discus that I truely understand that it is not in the fish's or your best interest to "stretch" the friendship with minimal care.. they may seem fine for a while but one day you will wake up to a major disaster in your tank..(I know this from earlier experience pre discus) Discus can live upto 10ish years and I really love them and want them to be with me as long as possible so.. you "must" do the right thing by them..

NB: my waterchanges have gone from 3ish hours each to about 35-40 mins thanks to changes in how I go about it.. So it really is not much time at all.. and when I get my water holding containers online I expect it to be even quicker.. yeah 8-)

OK I will get off my soap box now :roll:

BigDaddyAdo
Tue Jan 13, 2009, 04:48 AM
did you actually read the thread before replying?


If you have yet to understand the reasons behind running a filter then i would recommend that you do a whole lot more research before you even consider buying a discus.

Just google cycling your aquarium.


Ado

Yes i did. It clearly shows that you dont understand and have missed the point completely.

BTW there is no need to be so rude.




Ado

1fish2fish3fish
Tue Jan 13, 2009, 06:39 AM
As Im sure this will be the end of the thread.. I will post anyway.. :D

Im knew "H" would be around sooner or later.. and said what he would tell anyone who wants to listen..

Poster seems you have missed the point alltogther on " Basic fish keeping" never mind the Discus keeping...theres no real short cuts to keeping Discus..
As was told to me when I thought Id set up a diccus tank, These fish come from one of the cleanest waters in the world..just that alone kept me reading and I learnt alot..
myself and Many other here starting a discus tank are in it for the long term, of keeping them.
I too have been keeping fish for over 25 yrs, just never Discus so I turned here for some info and help.. and I got it..
Tell yah what I did when my alarm rang a 6:00 am..today.. went to the kitchen made the coffee, as that was running I was checking my tank.. before I even poured my coffee I had everything ready for the water change.. cause doing it later would not do.. it was now..
thats the commitment I am taking for my fish..cause I want a healthy tank and the fish to thrive.. so In the evening I can sit back and enjoy..
I care for 4 tanks and 5 is in the works..
then I go to twork and care for 50+ tanks.. and I love it..
proud to say I am one of the few ppl in the fish business that can offer proper info and care to my customers for I knoe its hard to come by in some LFS.. :D
later..

1fish2fish3fish
Tue Jan 13, 2009, 06:42 AM
hmm, how did that happen.. maybe its time for bed..lol
someone can take one out..hehe

1fish2fish3fish
Tue Jan 13, 2009, 07:13 AM
but i don't understand the act of continuous frequent water changes having any positive impact on the health of the fish.


WOW! "Water quality" is everything to every fish!!!! not just Discus..

TW
Tue Jan 13, 2009, 09:29 AM
Hi dexxl

I have a 74G tank, so on the assumption that it is 10G per adult discus, I am understocked. The tank has 4 adult discus (they are doing their QT time in the tank - later I do intend stocking it up to 7 adults).

Anyway, it is filtered by 2 x eheim pro II 2026. Therefore, it is over filtered.

Tank is bare bottom. This is a picture of the waste I vac'd up today. It's just their poop, as they have eaten all their food. It is only one (1) day's waste - actually a bit less, as it hasn't been 24 hrs yet since the last clean.

Discus are big meaty fish. They can do a lot of poops in 1 day.

1fish2fish3fish
Tue Jan 13, 2009, 05:53 PM
Great post TW..
and as Im sure you feed your fish a number of times a day.., young, juvs,or adults, its not rocket science, more they eat the more they poo.. :lol:
I still did a water change later that evening, after feeding them twice within a 3 hr period..only 20% ..I see it as when the readings show 0 ammonia, its there on the rise shortly after..
I think hes forgotten the "3" in filtration.. Biological, mechanical, and Chemical..wonder if he knows where he fits into that..
btw, great filtration you have there.. Im looking at the same Ehiem, to bad I cant get it through my business ( it would be a little cheaper).. but Im not settling for less cause I get a better price.. will pay full elsewhere..

Dexxl, everyone understands your original post and your question at hand..reread back through to see what was said, "IT" realy does have an impact on your fish health long term..
you have a wonderful size tank there and would have a great set-up for keeping Discus..

BigDaddyAdo
Tue Jan 13, 2009, 07:49 PM
It will also have a negative effect in the short term imo.



Ado

Proteus
Wed Jan 14, 2009, 02:55 AM
Big Tank = Less Water Changes...

I think in some cases this would work, but as has been mentioned there are a lot of factors you need to look at. Water chemistry is a funny thing...

I have always been of the belief that the bigger the tank, the more stability you should have if a regular maintenance regime is adhered to.

At the same time, if something does go wrong, you have to scratch your head that little bit longer, and have a bigger job to get things back under control.

Regular water changes along with good filtration will generally keep you out of trouble.

Greggy
Wed Jan 14, 2009, 08:18 AM
I think having a larger tank provides many benefits, and are some not always easy to identify and/or measure. There is no doubt that if the stocking levels are low and the tank volume is high then the amount of time it takes for wastes like NO3 and TDS etc to build up will take longer to reach problematic levels, so that may translate into more time between servicing = less water changes.

But I think what many of the others are trying to say is that this sort of thinking (to minimise tank maintenance) should not apply to the keeping of Discus.

However I will not go as far to say that you should not even think about such an idea if keeping Discus and having low maintenance is your goal. A large tank (something like a 4x2x2 or bigger) with a good filter (like one of the big Eheims such as a Pro III 2080 or a 2260 Classic) with a very low stocking level of fish (such as 3 Discus, a couple of SAEs, a BN and maybe a small school of a dozen Cardinals) would probably work ok if you could manage to change 50% of the water every two weeks. I would think it would work out just fine, and if such a tank was heavily planted I'd say you might even stretch the water changes out to every three weeks and still be ok. But if you wanted to only change the water once a month to me that would begin to be getting into territory where instead of Discus you should consider keeping other types of hardy fish such as Angel Fish or perhaps African Cichlids. In fact if your tap water is hard African Cichlids could make a real case for themselves!

Anyway, remember that for fish their entire Universe is their tank, so at the very least the larger the tank you can get the better... and no one will argue with that.

Regards,

Greggy

dexxl
Thu Jan 15, 2009, 11:54 AM
Thank you Greggy and Thank you Proteus. that's all i wanted to know. and greggy,.. i'm sure i can find someone to argue with that, or at least think it's a waste of time....

another benefit i'm thinking (tho i'm not sure if it applies to discus) is that larger body of water, generally means faster growth for the fish.



I think having a larger tank provides many benefits, and are some not always easy to identify and/or measure. There is no doubt that if the stocking levels are low and the tank volume is high then the amount of time it takes for wastes like NO3 and TDS etc to build up will take longer to reach problematic levels, so that may translate into more time between servicing = less water changes.

But I think what many of the others are trying to say is that this sort of thinking (to minimise tank maintenance) should not apply to the keeping of Discus.

However I will not go as far to say that you should not even think about such an idea if keeping Discus and having low maintenance is your goal. A large tank (something like a 4x2x2 or bigger) with a good filter (like one of the big Eheims such as a Pro III 2080 or a 2260 Classic) with a very low stocking level of fish (such as 3 Discus, a couple of SAEs, a BN and maybe a small school of a dozen Cardinals) would probably work ok if you could manage to change 50% of the water every two weeks. I would think it would work out just fine, and if such a tank was heavily planted I'd say you might even stretch the water changes out to every three weeks and still be ok. But if you wanted to only change the water once a month to me that would begin to be getting into territory where instead of Discus you should consider keeping other types of hardy fish such as Angel Fish or perhaps African Cichlids. In fact if your tap water is hard African Cichlids could make a real case for themselves!

Anyway, remember that for fish their entire Universe is their tank, so at the very least the larger the tank you can get the better... and no one will argue with that.

Regards,

Greggy

TW
Thu Jan 15, 2009, 12:15 PM
What is the minimum size group usually recommended for keeping discus (unless they are a confirmed pair). Knowing they are a schooling fish, I'd thought it was a tad higher than 3 & that with 3, one is likely to picked on by the other pair. I haven't experienced this myself & it may not be correct, but I feel sure it's what I've read here. So maybe 4?
Regular water changes along with good filtration will generally keep you out of trouble.
But I think what many of the others are trying to say is that this sort of thinking (to minimise tank maintenance) should not apply to the keeping of Discus.

1fish2fish3fish
Thu Jan 15, 2009, 03:55 PM
that's all i wanted to know. and greggy,.. i'm sure i can find someone to argue with that, or at least think it's a waste of time....


I would most definatly argue with that as most have been in this thread.., but someone feels it might work, from thier own experiences..good luck then! it simply depends how you are looking at this hobby for you.. short term or long term..


another benefit i'm thinking (tho i'm not sure if it applies to discus) is that larger body of water, generally means faster growth for the fish.
that would apply to every fish!!! :roll: unless your talking of a Betta!..thats commmon sence!

I believe you are only reading what you want to hear...

Hollowman
Thu Jan 15, 2009, 06:25 PM
Dexxl,

I tend not to agree with Greggy. It is the build up of DOC's that is the other reason to change water. There is also a school of thought that say that the dominant fish also release a hormone into the water which inhibits growth. Leave that in the water for 2 weeks, a month, longer, you'll end up with a bunch of stunts. If that is what you want....go for it.

You say: i'm sure i can find someone to argue with

I think you must have far more experience than me, I use personal experience and that of my piers, whome I respect, however experienced they be. I try to help, but it seems you like to argue, we are not here for that.

H