# 90% weekly water changes



## Halley (11 Sep 2016)

Hi - I'm just throwing this out there but in my heavily planted tanks I do 90% weekly water changes.  The fish seem fine once the temperatures are similar and the plants love it!  I think you can do crazy water changes if you have lots of plants as they do the filtering rather than bacteria.  Anyone else with me?


Sent from my iPhone using Tapatalk


----------



## mort (11 Sep 2016)

Why do you feel you need such large changes? Do you really heavily dose or have a massive bioload?


----------



## Halley (11 Sep 2016)

I have loads of plants and quite a high bio load but the theory is based on the fact the fish are in fresh water the is constantly been renewed


Sent from my iPhone using Tapatalk


----------



## Aqua360 (12 Sep 2016)

Halley said:


> I have loads of plants and quite a high bio load but the theory is based on the fact the fish are in fresh water the is constantly been renewed
> 
> 
> Sent from my iPhone using Tapatalk



If you can match the parameters very closely, then have at it; but why take the risk? If you need to do 90% changes on a tank, that indicates overstocking to me...in my humble opinion


----------



## Easternlethal (12 Sep 2016)

I have to do large water changes too because of my high bioload from mistakenly purchasing a pregnant guppy few months ago. They breed like rabbits and faster than I can give them away. 

That said my water is soft and only very lightly chlorinated and my fish and inverts don't seem to mind. 

The only thing which stops me is I have critters and don't really like having all of them concentrated in only 10% of water with all my fish. 

With lots of plants, baby critters may not be fast enough to swim down to where the water is and risk getting eaten if they do. 

The better solution is,  of course, to do more frequent water changes.


----------



## roadmaster (12 Sep 2016)

I do 50 % water changes out of habit mostly.
Have lot's of plant's and fair bioload with ever breeding bristlenose.
Another heavily planted tank I have with fewer fish, could go a month or more without a water change for the plant's act as biofilter and quickly use ammonia and nitrates.
Hardest part with larger water changes, is source water that changes in chemistry at the whim of local water treatment plant.Thankfully it only happen's a couple times a year in spring /fall and I can store water for a few week's in large barrel.
Have never had need of changing more than 50 % which I might do twice a week with larger number's of fishes or young fishes being fed more than once a day.
Opinion's vary.


----------



## PARAGUAY (12 Sep 2016)

One of the experts Ceg I am sure I read in one of his posts will do 90% in his 6ft tank no issues.


----------



## foxfish (12 Sep 2016)

If you want to do a 90% water change then you do that. I don't think we a have a planted tank police force....
Personally I would never do that as part of a regular routine because I feel it would put far to much unnecessary stress on my fish!
Even a 50% water change is going to stress the fish during the actual procedure but just leaving the fish in a few inches of water seems totally unnecessary in my opinion.


----------



## ian_m (12 Sep 2016)

Easternlethal said:


> That said my water is soft and only very lightly chlorinated and my fish and inverts don't seem to mind.


How do you know, lightly chlorinated ??? If strong enough to keep the water sterile then stong enough to kill bacteria in your tank and burn fishes gills. Always dechlorinate.

Even more so if water company add emergency dosing chloramine. Many many people on this forum have wiped out all their £100's of fish in one water change after water company dose chloramine. Prime and sodium thiosuplhate cosy b*gger all per dose.


----------



## Easternlethal (12 Sep 2016)

sorry I don't believe the OPs question is about chlorination so I'm not going there.


----------



## roadmaster (12 Sep 2016)

Believe that large water changes are not stressful if they are the norm throughout the tank's life, and...the source water stay's consistent.
It is sudden changes that have negative affect, such as water changes far and few between,sudden increase in chlorine/chloramines .
Discus purist's routinely change large volumes of water daily, and fishes do not seem to mind.
Source water suddenly changing in chlorine/chloramine content would be only concern for me with larger water changes, along with possibly sudden temp change.
Is why many store water and preheat/pretreat before using. No?


----------



## Halley (12 Sep 2016)

I think the point is - whatever works for you - then do it. 


Sent from my iPhone using Tapatalk


----------



## Halley (12 Sep 2016)

Next time I'm going to do a 91% water change just to annoy people 


Sent from my iPhone using Tapatalk


----------



## kadoxu (12 Sep 2016)

Halley said:


> Next time I'm going to do a 91% water change just to annoy people


I would stick to 89.99%...


----------



## Halley (12 Sep 2016)

That's a dangerously low figure - how you done your research? 


Sent from my iPhone using Tapatalk


----------



## foxfish (12 Sep 2016)

roadmaster said:


> Believe that large water changes are not stressful if they are the norm throughout the tank's life, and...the source water stay's consistent.
> It is sudden changes that have negative affect, such as water changes far and few between,sudden increase in chlorine/chloramines .
> Discus purist's routinely change large volumes of water daily, and fishes do not seem to mind.
> Source water suddenly changing in chlorine/chloramine content would be only concern for me with larger water changes, along with possibly sudden temp change.
> Is why many store water and preheat/pretreat before using. No?




I think most of what you say is true but..... there is the issue of how the water change is done and how long it takes.
For instance - if Fred carried out  a 90% water change in his 300lt  tank, after around 80% of the water change, his discus would by lying on their side ..... & for how long?
My point is not about the how much water is changed but the fact that any fish will be left in very little water, in my opinion this will cause them stress!
If Fred had a system that allowed 300lt (or 100%) of treated water to trickle in every 24 hours without the tank level dropping, then that would be great....
I think the more standard 50% is set mainly for the benefit of the fish, if we were discussing a 'plant only tank' then I can see no reason to limit any size water change.


----------



## AverageWhiteBloke (12 Sep 2016)

Ultimately fish are sensitive to sudden changes in water chemistry and temp. In a half filled tank each jug of water added (if that's how you do your changes) will make a very small change to the make up of the water. In a tank with just 10% original water remaining each jug of water will make a significantly bigger change unless of course care is made to make the new water as close in make up as the existing water.

It's an either or situation I guess, with a 50% change you can add water not exactly like the existing water and do it a bit quicker or do a 90% change with water very similar to the existing and do it a bit slower. In the case of the Discus people I find that most will do the big water changes but with water they have took a lot of time matching in both make up and temp. Obviously lowering the water level to a point where the fish are laying on their sides or struggling to find water deep enough is not going to make them happy.


----------



## alto (12 Sep 2016)

I like doing large water changes too  - even when there are no fish in the tank 

I have tall tanks so even though I drop the water level slightly past the 2/3 mark on the glass height, given that substrate has a major volume contribution in that bottom 1/3 of the tank, it's likely my water change by volume is significantly greater than 70%

So why am I stressing my fish?
Because they respond so positively to the large water changes.

I use a Python system & the time lapse between 50% mark on the glass - then 70% - then return to 50% is NOT long (sorry don't have the actual time but I can complete the water change in under 30 min)
I don't move about in the tank or clean walls etc when the water level is below the 25% mark on the glass (ie only slightly lowered water level from full - less splashing this way)

Perhaps others do their tank maintenance at lowered water levels & that is why they find the water changes to be noticeably stressful to fish.

I also offer a favorite food shortly after water change - the wild caught S vaillanti I have in a too small Q tank (ie they already have cause for stress) constantly request food through the water change process, & immediately gather for their expected food after water change is complete.
I plan a 50% water change in this tank as it's only 30cm high (& I keep low substrate height in this tank as well) - when I accidentally drained more like 80% of the water & fish had disappeared into the back areas, as soon as water level returned to even 50%, fish were back out asking after food, water change complete & they didn't act as if I'd turned their water parameters upsidedown or even sideways  

In their natural life, fish experience stress as well, those stress hormones generally "activate", increasing metabolism/catabolites - momentary stress is not the same as continual stress (which strongly suppresses fish immune function among other factors) 

I do have some fish that display discomfort with water change, but they are already showing stress colors/behaviour before I've removed even 10% of the water ... and they quickly return to life as normal once the water change is completed.


Most freshwater fish kept in aquaria come from natural waters where there are seasonal changes, even significant temperature & pH swings through the course of 24hours (all this is documented in scientific journal articles), fish from these waters have metabolic mechanisms designed to stabilize their biochemistry against change - I'm much less concerned about matching exact water parameters with these species than those that are endemic to very stable waters. 

But anyone that is not comfortable doing more than a 25% water changes, is doing just fine too


----------



## Halley (12 Sep 2016)

Yes - I agree - i use a phython too and have small fish in a juwel vision who have plenty of space even in 10% of water. The water takes about 20 mins to fill back up and is kept at a similar temperature.  The benefits to the plants are huge I think.  Happy plants generally equal happy fish. There is also some water in the external filter as well.  I'd say I do 75% water changes (not really 90%).  My fish seem to love the fresh water - after a few minutes the Cardinals tetras are swimming all over the place.  Every tank is different and has different requirements. The fish get stressed when I have my hand cleaning but not when the water is filled.


Sent from my iPad using Tapatalk


----------



## Easternlethal (13 Sep 2016)

I used to syphon then refill. But I can tell everyone hates the syphon because as that happens the water level drops and everyone hides / goes very still. I think this stresses them. Then during the refill everyone comes out and plays, sometimes even trying to swim into my hose. 

So lately (ppl who disagree with large water changes close your eyes) I have been thinking of attempting a simultaneous syphon / refill with separate hoses. Just like a real life flowing river right?


----------



## rebel (13 Sep 2016)

Drip system FTW,


----------



## Halley (13 Sep 2016)

Would you get the same benefit of a drip system in a heavily planted tank?


Sent from my iPhone using Tapatalk


----------



## Aqua360 (13 Sep 2016)

Easternlethal said:


> I used to syphon then refill. But I can tell everyone hates the syphon because as that happens the water level drops and everyone hides / goes very still. I think this stresses them. Then during the refill everyone comes out and plays, sometimes even trying to swim into my hose.
> 
> So lately (ppl who disagree with large water changes close your eyes) I have been thinking of attempting a simultaneous syphon / refill with separate hoses. Just like a real life flowing river right?



good theory in practice, but i imagine you'd end up taking out some of the fresher water as well; not changing as much water as you would like.

I usually aim for water changes at just over 50%, to combat climbing nitrates etc. I don't do that in tanks with shrimp though, since those minor fluctuations mentioned above, can easily kill shrimp. An interesting notion on the python water changer (which i used up until recently), is that i only like to put in water from the cold tap; whenever hot water is pumped in it's cloudy and makes me suspicious of the hot water tank or whatever. That's obviously a reason individual to me, but food for thought if you have copper pipes etc and inverts


----------



## ian_m (13 Sep 2016)

Aqua360 said:


> but food for thought if you have copper pipes etc and inverts


Think about it, the copper pipes cannot dissolve in any significant quantity or else we would all be living in flooded houses where all the copper pipes have dissolved away !!! Yes some copper does dissolve but generally this is due to contamination settling in the pipes and reacting with the copper, especially true of water is allowed to stand in pipes for a long time (years usually). Any flowing water will remove contaminants and any water hardness (or phosphate dosing in soft water areas) will coat the pipes and prevent any chemical access to the copper.


----------



## dw1305 (13 Sep 2016)

Hi all,





Aqua360 said:


> whenever hot water is pumped in it's cloudy


This is likely to be due to the low solubility of gases in warm water, and is just a fine suspension of CaCO3 particles. 

Because carbonate solubility is dependent upon the concentration of CO2 in the water, and gases are less soluble at higher temperatures, warm hard water can hold less CO2, and this means that CaCO3 is precipitated. 





ian_m said:


> Any flowing water will remove contaminants and any water hardness (or phosphate dosing in soft water areas) will coat the pipes and prevent any chemical access to the copper


 Ian is right, because the limits on <"EU lead (Pb) are so low">,  the water companies use techniques (<"PIMS">, NaOH addition) that eliminate the chance of lead getting into the water supply, and these techniques also reduce the levels of zinc (Zn) and copper (Cu)

cheers Darrel


----------



## Aqua360 (13 Sep 2016)

dw1305 said:


> Hi all,This is likely to be due to the low solubility of gases in warm water, and is just a fine suspension of CaCO3 particles.
> 
> Because carbonate solubility is dependent upon the concentration of CO2 in the water, and gases are less soluble at higher temperatures, warm hard water can hold less CO2, and this means that CaCO3 is precipitated.  Ian is right, because the limits on <"EU lead (Pb) are so low">,  the water companies use techniques (<"PIMS">, NaOH addition) that eliminate the chance of lead getting into the water supply, and these techniques also reduce the levels of zinc (Zn) and copper (Cu)
> 
> cheers Darrel



this is good information


----------



## roadmaster (13 Sep 2016)

foxfish said:


> I think most of what you say is true but..... there is the issue of how the water change is done and how long it takes.
> For instance - if Fred carried out  a 90% water change in his 300lt  tank, after around 80% of the water change, his discus would by lying on their side ..... & for how long?
> My point is not about the how much water is changed but the fact that any fish will be left in very little water, in my opinion this will cause them stress!
> If Fred had a system that allowed 300lt (or 100%) of treated water to trickle in every 24 hours without the tank level dropping, then that would be great....
> I think the more standard 50% is set mainly for the benefit of the fish, if we were discussing a 'plant only tank' then I can see no reason to limit any size water change.



Agree,Can think of no instance where 90 % water change was needed in any of the tank's I have run for year's now.
Maybe accidental spill of fish food container or medication might make me consider it.


----------

