Makeup water & water changes

[birddogs]

Reading another thread it seems a discussion about
make up water & water changes  that offers a lil more information than a basic reef keeping book is in order.
Anyone who has been around the block feel free to throw in Your 2C


as we all know the basic book suggests we match all parameters as closely as possible so the system doesn't
get up set  I also saw some mention of the continuous water change method in the afore mentioned thread

first Ill discuss water changes & present the math that applies to volume of change in a basic format Note :
this in no way reflects how much water You need to change  but compares equal volumes at different intervals

for this equation we are going to
start at
 50ppm total impurity's, with a rate of gain in impurity's
of 5 ppm per week just for the sake of illustration

10% change  once a week =    50 ppmX.9=45ppm+5ppm gain   or 50 ppm at the end of the week

5%  2x a week   = 50ppm. x .95= 47.5PPM +2.5 ppm. mid week gain 0r 50 ppm mid week -- repeat late week
for  50 ppm end of week

all the same  ??  not when You compare the water quality  during the first 1/2 of the week by amortising the rate of gain over 7 days  or .714 ppm Per day( rounded to the nearest thousandth)
10% change
day 1         day 2        day 3        day 4
45PPM     45.714      46.428       47.142

5%
day one        d2             d3                 D3.5                d4
47.5          48.214     48.928       49.285/47.85    48.564

the net result is the larger change provides a sweet spot early week  vs stable poorer quality across the board pick your poison

on to make up water  it is possible some people just starting out get the impression   that make up water has to match the tank as close as possible & that's a fair place
to start as You enter the hobby & should be suggested in every book on the market  . no doubt there are those out there who will just dump a bucket in there tank so
reference material needs to address those people too

however there can be many reasons a reef keeper may need to adjust the parameters of the water or there make up water may be a lil off

example: old systems tend to be organically rich causing
lower  PH   so if ph in the system were lower than
the make up water a person is best advised  not to adjust the make up water  but to add it slowly enough
to  ACCLIMATE  the system to the adjustment as the system needs adjustment  & make up water can be a fine way to add & adjust as necessary the key here is everyone needs to learn there systems well enough to offer
acceptable rates of introduction of water & chemicals
so from that perspective it is not allways the goal to match  tank parameters & make up water. But it should more so be the goal to match the rate of introduction to the similarity of water Parameters & make up water

just a few points to ponder
Kevin

[reeftanknewbie]

Man,
thanks so much for posting this.  Gives me a lot to think about (and try to remember....haha) when thinking about water changes and make up water. so if i understand this correctly the outcome at the end of the week is still at 50ppm in your example regardless of doing a 10% water change at one time or splitting it up over the week.  Would it be better if you wanted to do small changes to due them at a greater value of lets say 15% so that the end of the week ppm may be lower then 50?  Hope I am understanding this correctly and making sense here.

 

[birddogs]

as applied to the example above 3-- 5% changes per week will result in net waist removal of 2.39 ppm or 2.5ppm with 15% one shot  the first week  however each week the net waist removal
will decrease as 5% of nothing is still nothing
   the key is to be aware of the average net gain of waist  & stay
even or a lil ahead of it  to maintain a reasonable environment & prevent the necessity of doing massive changes    also note the advantages of each ,amortising
your changes improves available trace during the week
one shot improves water quality a lil better  its a matter
of picking your poison.  for most people there ideals evolve over time as there need to mother there system
diminishes

[jonbry]

Over the years I've been in the hobby I've found what works best for me may not for someone else.  There are a number of factors that have to be considered and each system will be unique:
 
1) The bio load.
2) The quality of equipment used such as types of 
    filters used-mechanical, biological, chemical or a
    combination of all three.
3)  Quality of skimmer being used.  This type of
     filter can remove huge amounts of organic
     matter if of good quality.
4)  Is it a reef system with primarily soft coral or
     SPS or LPSs or a combination of all three or a
     FOWLR system.  Different animals will utilize
     more or less of some components so a balance
     of those elements for success needs to be test
     ed individually for best results.
 5) The quality of salt being used.  There are so
     many different brands yet they all show after
     tests to have significant variance in their claims
     to mimic natural sea water in what they
     contain.
 
With so many variables involved we truly cannot duplicate an environment that is so complex but can only hope to come as close as possible for the long term care and health of our animals.  I do a 20% water change every two weeks.  During that time in between I constantly monitor Ph and salinity levels and use both mechanical and chemical filtration methods for organic waste removal.  I currently have a mixed reef set up and have found over the years this method has worked best for me.

[reeftanknewbie]

Over the years I've been in the hobby I've found what works best for me may not for someone else.  There are a number of factors that have to be considered and each system will be unique:
 
1) The bio load.
2) The quality of equipment used such as types of 
    filters used-mechanical, biological, chemical or a
    combination of all three.
3)  Quality of skimmer being used.  This type of
     filter can remove huge amounts of organic
     matter if of good quality.
4)  Is it a reef system with primarily soft coral or
     SPS or LPSs or a combination of all three or a
     FOWLR system.  Different animals will utilize
     more or less of some components so a balance
     of those elements for success needs to be test
     ed individually for best results.
 5) The quality of salt being used.  There are so
     many different brands yet they all show after
     tests to have significant variance in their claims
     to mimic natural sea water in what they
     contain.
 
With so many variables involved we truly cannot duplicate an environment that is so complex but can only hope to come as close as possible for the long term care and health of our animals.  I do a 20% water change every two weeks.  During that time in between I constantly monitor Ph and salinity levels and use both mechanical and chemical filtration methods for organic waste removal.  I currently have a mixed reef set up and have found over the years this method has worked best for me.

I would agree that everything you put in your tank adds a degree of planning and care when it comes to maintaining it's environment as closely as possible to nature.  I use very similar methods (except I do weekly 5 gallon water changes) of maintenance on my tank as you do and so far am having some good results although I have limited livestock so far.