Dosing vs H2O changes for alk & cal

[Aurortpa]

So I did another test in order to get my dosing for alk and cal in order. My mag seems to be maintaining within range.

 

I calculated I am losing about .5 dkh a day and about 15 mg/l of cal.  That’s 3.5 dkh a week and  105 cal.  

 

I have been testing for weeks before water changes...I even tested my calculations by checking my dhk after a water change.

 

For instance, my dkh before water change was 8, my water change is ~25% volume with new water at 11 dkh so with respective ratios that effectively should only raises my dkh to 8.75, then adding my alk dose prior to my new adjustment would push it to 9.5.  I confirmed it at 9.5 the day after.

 

So I calculated the dose for a twice a week schedule based on dividing my tank’s weekly consumption rate in two, so that’s 1.75 dkh and 52.5 cal I need to replenish then on my two dosing days.

 

With that said, how would it be possible for me  to rely on solely water changes, no dosing, like I’ve read some do successfully? Is their consumption rates significantly lower?  Do they do larger +50% water changes?  Just curious how does that actually brings you to target alk & cal targets?

 

[Aurortpa]

Nobody? Lol

[seabass]

Water changes are an inefficient way to replenish consumed elements.  People that don't have to dose usually only keep soft corals (which have a much lower consumption of calcium/alkalinity than stony corals) or only have a few smaller LPS corals and/or little or no coralline algae.

 

However, it's true that by changing enough water, you can stabilize levels (although somewhat lower than levels of a newly mixed batch of saltwater).

http://reefkeeping.com/issues/2005-10/rhf/index.php

 

[mitten_reef]

Answer is, it depends on your personal tolerance on the fluctuation, AS WELL AS your corals tolerance of fluctuations.  Some ppl prefer rock steady parameters, some don't care as much.  The general consensus is that the steadier the parameters are, the better growth and coloration you'll likely get.  

 

These two threads had been quite active the last week or so....about water change and dosing.

why not just browse through there and asking a bit more specific questions to the ppl in those two conversation?  

Edited June 15, 2018 by micoastreefing
changed in italics

[Aurortpa]

Excellent!  Thanks @seabass & @micoastreefing!  That info is very interesting!!!  As usual, seems like it just really depends on the many variables surrounding the diversity of each of our tanks: livestock, equipment, and intended maintenance schedules.  Still, very valuable information.  Curious how I see some claim their tanks look better after reducing water changes.  I've been told at least once a week but now with me dosing, perhaps I should let it go longer?

[seabass]

1 hour ago, Aurortpa said:

Curious how I see some claim their tanks look better after reducing water changes.  I've been told at least once a week but now with me dosing, perhaps I should let it go longer?

I've read where reducing water changes typically benefits a tank short term.  However, unless you have excellent nutrient export and methods to remove organics, trouble usually soon follows.  Sometimes you read about these problems, other times you don't.

 

Frequency depends on the volume of changes, bio-load, feeding, alternate nutrient export mechanisms, etc.  Again, if you don't have other ways to export nutrients and organics, reducing water changes can lead to a buildup and eventual problems.

[Aurortpa]

3 hours ago, seabass said:

I've read where reducing water changes typically benefits a tank short term.  However, unless you have excellent nutrient export and methods to remove organics, trouble usually soon follows.  Sometimes you read about these problems, other times you don't.

 

Frequency depends on the volume of changes, bio-load, feeding, alternate nutrient export mechanisms, etc.  Again, if you don't have other ways to export nutrients and organics, reducing water changes can lead to a buildup and eventual problems.

Well I definitely don’t have excellent nutrient exports yet lol. Yeah, it seems logical that overtime some parameter could creep in the wrong direction—makes sense to me!  Best to probably test over time to see when my nitrates would start to rise to see when I could do a water change but until my tank stabilizes, I’ll stick to once a week.