Water change question

[darth tang]

I perform water changes. My question is this, why do we do water changes on fish only tanks. If the parameters are good, why is this done. I am not going to stop doing this no matter what is said. I just want the scientific reason we do this for fish only tanks. Is there something in the water the fish remove that we can't test for?

 

[nereef]

If a water change isn't done for a while in a fish-only tank, you'll know it. Things get nasty. Cyano, smelly water, etc. Fish remove trace elements and use them up(marine fish constantly drink water to maintain osmoregulation). Also, water changes keep nitrates lower and more stable by phsysically removing them and replacing with "new water." You're probably looking for more, but that's all I can tell you.

 

[doodle1800]

Originally Posted by Darth Tang
I If the parameters are good, why is this done.
My guess is that you (I) cannot test for every parameter involved with quality water. Plus, while testing "good" one day, paramters might change more quickly with older water.
humble opinion...

 

[nereef]

Doodle, that would make sense. the more "trace elements" that are used up would mean less resistance to change in pH, etc.

 

[darth tang]

That is what I figure...but I am looking for the scientific explanation.

 

[doodle1800]

First of all "we" don't do water changes just for fish only tanks. Water changes are important and necessary for all types of tanks.
Second, stating that parameters are "good" is a vague statement. You can't possibly test all the elements involved in saltwater, especially trace elements. You, like all aquarists, test parameters like salinity, calcium, nitrates, nitrites, hardness, oxygen, iodine, ph, ammonia, copper...etc... I'm almost sure you don't test oxygen and carbon dioxide levels for instance.
Here's a list of the top 14 of the 70 trace elements considered to be essential for sea water.
Chromium (Cr) 0.00005
Cobalt (Co) 0.0005
Copper (Cu) 0.003
Fluorine/Fluoride (F) 1.3
Iodine/Iodide (I) 0.05
Iron (Fe) 0.01
Manganese (Mn) 0.002
Molybdenum (Mo) 0.01
Nickel (Ni) 0.0005
Phosphorus/Phosphate (P) 0.07
Selenium (Se) 0.0002
Tin (Sn) 0.003
Vanadium (V) 0.002
Zinc (Zn) 0.01
These trace elements are absorbed naturally and by organisms in your tank, they should be replenished by doing water changes.
So - when you say your parameters are good, its not enough of a test to state that....

 

[doodle1800]

From a friend >>>>>>>>>>>>>
Consider:
1) something in changing at 1ppm each day
2) water changes are conducted at 1%/day or multiples. (1%/day, 10%/day, 30%/30 days etc)
3) consider only the effects of the water changes.
4) the system runs long enough so that the parameter just before the water change is essentually the same. Like within .000001% or so.
Question:
What is the value of that thing just just before any water change?
answer
100ppm +the amount in the replacement water.
In other words the water changes result in 100 times the daily change.
Consider nitrates increasing at 1ppm/day and 0 nitrates in the replacement water
100%/100days. In a 100 days, the parameter builds up to 100ppm then drops to 0 then 100 days later is 100ppm again
50%/50 days. In 50 days it is 50. then drops to 25. then up yo 75. at 100ppm it drops to 50 then up to 100 then down to 50. So that is the point where it tends to.
other values:
30%/30 days 100->70->100
20%/20 days 100->80->100
10%/10 days 100->90->100
1%/1 day 100->99->100
continuous flow 1%/day 100ppm
And that applies to everything in the water. So 105/week or 30%/month type water changes result in a build up of around 100 times the daily change.
What is important is to limit the daily change. that is why dosing calcium and alk are require even with water changes. And why nitrates and phosphate rise after several month even with water changes. And people get algae problems and lose fish and corals.
But it is possible and easy to balance out the system to where the daily changes are so small the tank runs for years without water changes. But that requires people to look for other methods and not rely on water changes as a primary means of controlling things.

 

[peter1215]

i just started a fowlr 120g tank. so what is the rule of thumbs for water changes with a reasonalbe fish load. is a monthly 10% water change enough ?

 

[bailey52]

Peter... re-read his post...
where in Nj are you

 

[segsig]

Bailey52-where in South jersey are you? I'm in Toms River...if you're near me, which LFS do you trust?

 

[bailey52]

Your more south than me... Im in the moorestown area and cherry hill... There are 2 good places in medford and a spectacular one in blackwood...

 

[peter1215]

Originally Posted by Bailey52
Peter... re-read his post...
where in Nj are you
i'm in Oldbridge nj. I just came back from a place in ocean NJ. its awesome but fish are pricey. there tanks and stands are at cost so noone beats their prices. email me if you their name and directions.
pistolpete1215@yahoo.com

 

[roadrunner]

i live in medford and i dont know of any LFS here...i think you meant the 2 in marlton right down the street from one another...
Bailey52 and segsig i probably live inbetween the 2 of you...haha!
were is the LFS in blackwood and what is the name...my gf lives near blackwood and i've been looking for another LFS...

 

[roadrunner]

i live in medford and i dont know of any LFS here...i think you meant the 2 in marlton right down the street from one another...
Bailey52 and segsig i probably live inbetween the 2 of you...haha!
were is the LFS in blackwood and what is the name...my gf lives near blackwood and i've been looking for another LFS...
...Darth Tang just to put into perspective for you...i have a 26 gal tank and i perform a 10% or 3 gal water change every week!

 

[bailey52]

yes just went to the one on 73 in marlton today... fish... ehhh had nothing.. their stock wasnt exactly looking healthy either... anyway the one in blackwood is spectacular... off 42, exit 8 make right at end of ramp one mile up on left behind friendlys. called aquarium center they have prob 200 saltwater tanks.. a little pricey but the fish are fantastic

 

[roadrunner]

what about corals...for the LFS in blackwood? also...do you know about the NEW LFS going up?

 

[bailey52]

corals there are wonderful... no what new one?

 

[roadrunner]

You know were Aquarium Authority use to be...next to party warehouse on rt. 70? That place left and now there is a new LFS going into it...i pass it when i go to school (ROWAN)...not open yet, but under construction...a friend of mine is going to be working there and suposidly the designer of the baltimore aquarium helped in designing this place...i'm excited to see the place when it opens!!!!

 

[bailey52]

oh i heard about it.. there is on... not on 73 right off it tho.. down near the GMC dealership.. i went into it once.. it was weird.. like there were stairs and hallways.. felt creepy like you were in someones house... and they didnt have anything

 

[roadrunner]

yea thats the place but there is a new LFS going in ther called Living In Color and they redid everything...it's not open yet but from the road i can see some things...and they put alot...and i mean alot...of tank upstairs...i'm excited to see it when it opens!