# water changes on a overstocked tank with out hurting my ph



## tiran (Apr 27, 2007)

i have a overstocked tank its a 135g with 8 pygos in it anywhere between 5'' to 6'' to 9'' my nitrates where really high like 50ppm how much water should i take out with out hurting or altering my ph whats the most i should be taking out of a 135g tank weekely and how often tell me in gallons. I was doing 50% somtimes 60% every two days somtimes every 3 to 4 days before i was told i was doing to many even on a overstocked tank, tell me how much i should be taking out i know its based on your nitrates but give me a good guess and i also feed every day


----------



## Nick G (Jul 15, 2007)

how long has the tank been established?


----------



## tiran (Apr 27, 2007)

Nick g said:


> how long has the tank been established?


for about 11 months 12 in febuary


----------



## Nick G (Jul 15, 2007)

i think feeding every day may be too much. when you change water do you use the gravel vac as well?
cus leftover food will raise nitrate levels. 
so far as PH, i am not sure, Shanker and Bullsnake and a few other guys are good with these kinda questions.


----------



## Dr. Giggles (Oct 18, 2003)

Tiran, don't worry about how many water changes you do. Too many water changes is never a bad thing. The answer you want is how much of a percentage water change to do and how many weekly to maintain a steady pH and to keep your nitrates down to a healthy level. You need to post up your pH and kH from tap and tank for me to get a handle of what you're dealing with. I have well water with a pH of 7.0 (pure water) with a kH of around 70 ppm. When I had 10 4-5"ers in a 125G I needed to do a water change of 30% every 2-3 days just to keep the nitrates in check and the pH stable. If i did a water change once a week my pH would drop to about 6.2. Every 3 days worked out pretty good. Anyways that tank had sand in it so it did not alter my kH or pH. I have other tanks that have crushed coral as a substrate and the pH in those tanks are a constant 7.6. If you need to add kH to your water crushed coral, limestone, or baking soda work wonderfully. The coral and limestone are preferred because once added your kH will start to rise and in turn your pH will rise a bit and stay stable with your bio load. All you'll need to worry about then is keeping nitrates down without the worry of altering your pH.

50-60% water change is only safe if the pH out of tap is equal to the pH in the tank. If your pH is much higher out of tap stick with no more than 33% water changes. If you can feed every other day for now and change 33% water every 3 days, test your water and see if that works for you. I've known some people on this board with overstocked tanks much more than yours and they were doing daily water changes basically. I hope I made sense of this to you.


----------



## tiran (Apr 27, 2007)

Dr. Giggles said:


> Tiran, don't worry about how many water changes you do. Too many water changes is never a bad thing. The answer you want is how much of a percentage water change to do and how many weekly to maintain a steady pH and to keep your nitrates down to a healthy level. You need to post up your pH and kH from tap and tank for me to get a handle of what you're dealing with. I have well water with a pH of 7.0 (pure water) with a kH of around 70 ppm. When I had 10 4-5"ers in a 125G I needed to do a water change of 30% every 2-3 days just to keep the nitrates in check and the pH stable. If i did a water change once a week my pH would drop to about 6.2. Every 3 days worked out pretty good. Anyways that tank had sand in it so it did not alter my kH or pH. I have other tanks that have crushed coral as a substrate and the pH in those tanks are a constant 7.6. If you need to add kH to your water crushed coral, limestone, or baking soda work wonderfully. The coral and limestone are preferred because once added your kH will start to rise and in turn your pH will rise a bit and stay stable with your bio load. All you'll need to worry about then is keeping nitrates down without the worry of altering your pH.
> 
> 50-60% water change is only safe if the pH out of tap is equal to the pH in the tank. If your pH is much higher out of tap stick with no more than 33% water changes. If you can feed every other day for now and change 33% water every 3 days, test your water and see if that works for you. I've known some people on this board with overstocked tanks much more than yours and they were doing daily water changes basically. I hope I made sense of this to you.


well i know i dont have a kh tester but i know my tap waters ph is around 7.6 to 7.0 and thats what i been reading in my tank so i guess im good on that. So doctor giggles let me make sure i understand you, if my tap water ph is the same as my tank ph and my nitrates are at about 20 to 30 even 40ppm every other day somtimes every two days aslong as i keep changing my water according to my nitrate levels ill never have to worry about my ph droping because im adding the tap water back in with the ph of about 7.6 to 7.0 to quickley,because i have noticed in the past that if i didnt do a water change for a week the ph would be at 6.0 so basically keep up with routine water changes as needed and i wont have to worry. One more question you know my tap water is at about 7.6 by the time its time for me to do a water change my ph in my tank has droped allitle to about 7.2 or 7.0 but my nitrates are 30ppm to 40ppm and i have to do atleast 40% to 60% to get my nitrates back to 5.0ppm to 10ppm will that little drop in ph at 7.2 then rise back up to 7.6 be bad for my fish or this really shouldnt be happening. Thanks for your help by the way.


----------



## Dr. Giggles (Oct 18, 2003)

tiran said:


> Tiran, don't worry about how many water changes you do. Too many water changes is never a bad thing. The answer you want is how much of a percentage water change to do and how many weekly to maintain a steady pH and to keep your nitrates down to a healthy level. You need to post up your pH and kH from tap and tank for me to get a handle of what you're dealing with. I have well water with a pH of 7.0 (pure water) with a kH of around 70 ppm. When I had 10 4-5"ers in a 125G I needed to do a water change of 30% every 2-3 days just to keep the nitrates in check and the pH stable. If i did a water change once a week my pH would drop to about 6.2. Every 3 days worked out pretty good. Anyways that tank had sand in it so it did not alter my kH or pH. I have other tanks that have crushed coral as a substrate and the pH in those tanks are a constant 7.6. If you need to add kH to your water crushed coral, limestone, or baking soda work wonderfully. The coral and limestone are preferred because once added your kH will start to rise and in turn your pH will rise a bit and stay stable with your bio load. All you'll need to worry about then is keeping nitrates down without the worry of altering your pH.
> 
> 50-60% water change is only safe if the pH out of tap is equal to the pH in the tank. If your pH is much higher out of tap stick with no more than 33% water changes. If you can feed every other day for now and change 33% water every 3 days, test your water and see if that works for you. I've known some people on this board with overstocked tanks much more than yours and they were doing daily water changes basically. I hope I made sense of this to you.


well i know i dont have a kh tester but i know my tap waters ph is around 7.6 to 7.0 and thats what i been reading in my tank so i guess im good on that. So doctor giggles let me make sure i understand you, if my tap water ph is the same as my tank ph and my nitrates are at about 20 to 30 even 40ppm every other day somtimes every two days aslong as i keep changing my water according to my nitrate levels ill never have to worry about my ph droping because im adding the tap water back in with the ph of about 7.6 to 7.0 to quickley,because i have noticed in the past that if i didnt do a water change for a week the ph would be at 6.0 so basically keep up with routine water changes as needed and i wont have to worry. One more question you know my tap water is at about 7.6 by the time its time for me to do a water change my ph in my tank has droped allitle to about 7.2 or 7.0 but my nitrates are 30ppm to 40ppm and i have to do atleast 40% to 60% to get my nitrates back to 5.0ppm to 10ppm will that little drop in ph at 7.2 then rise back up to 7.6 be bad for my fish or this really shouldnt be happening. Thanks for your help by the way.
[/quote]
You understand correctly. The 7.6 to 7.2 drop can be expected with your bioload. Its not the best, but I don't think its that bad either in that case. The one thing you may notice though is your fish flashing against the gravel. That is a tell tale sign your pH has adjusted and is starting to irritate the fish. What you can do to fix that is place a piece of limestone in the tank and your pH should never fluctuate after wards.


----------



## Dezboy (Apr 2, 2006)

I Do the same as giggles as reguards to water changing.............normally the ph in my tank is around 6.5 as a result of the water in my area, but the tap water is around 7.... yeah this isnt a drastic change but might be aenough to upset the fish a little, so i normally do 30% every 2 days............this alows a nice amount of fresh water and also it keeps my parameters in check................

135G with 8 fish in isnt too overstocked IMO, just as long as you have good filtration, good water circulation and are doing 30% water changes every 2-3 days then you should be fine..................


----------



## NegativeSpin (Aug 1, 2007)

I'm just beginning to understand the bicarbonate / carbonate buffering system quantitatively but this is what I have for tap water with 10 PPM bicarbonate and no carbonic acid being used to dilute aquarium water that has the equilibrium concentration of carbonic acid with atmospheric CO2 at 10PPM or 10^-5 Molar.
View attachment 160578


I'm sure everyones tap water is different so this only applies to the case 10 PPM bicarbonate from the tap and no dissolved C02 in the tap.

You can take an experimental black box approach to your tap water and after a week start with a 20% water change and test your pH before and after. You can zero in on the maximum amount you can change each time you adjust the percentage water change for a pH difference around 0.2.


----------



## pirayaman (Nov 3, 2007)

wo shanker your quite the genius arnt you if i even new what you had on that piece of paper id be smarter hahahaa im sure its very smart nice work


----------



## NegativeSpin (Aug 1, 2007)

bump


----------

