Reducing water changes: methods, benefits, challenges & discussion

[NanoRox]

I have been cutting back on my water changes for the past maybe two months to mitigate some of the water parameter fluctuations I was seeing with every change and to see if I would detect any water quality degradation as a result.  

 

This is certainly not a scientific test with a control etc. but just through my own casual observation my corals are doing much better now that I have actually cut back on my changes.  Please note I still make water changes but not every week as I was when I first started the tank.

 

i have been interested is seeing when my tank actually required a water change and I am finding that once a month is the sweet spot for my tank.  The only limiting factors that seem to necessitate the addition of “new” sea water is  my calcium and magnesium.  I use kalk that is also fortified with calcium and magnesium in my ATO but the calcium and mg uptake  of the tank seems to out pace it in about a month.  I suppose I could switch to two part but don’t have dosing pumps etc.  I do however dose Red Sea trace colors ABCD in my ato once a week.  My ATO has turned into a magic elixir these past few months.  

 

I am attaching my Ca and Mg graph that shows the gradual decline that then requires a small water change (about 4 gallons in my 14g nano). The Ca and Mg spikes show the result of the last water change.  They appear to spike at a different time because for what ever reason I tested those on different days.   

 

Anyway, just thought I would share. 

[empresto]

I've been trying something similar with my tank (inspired by some of BRS's videos) and have found that 2-part seems to do pretty well at keeping all those major elements.  The other thing I've tested for is Iodide, which seems to be used up pretty quickly as well.  I've started dosing Kent's Lugols Iodide as directed on the bottle and have managed to stabilize that number too.  However, I do wonder what other trace elements I'm depleting but I am not quite ready to spend the money on the Triton ICP testing.  So far, all seems health...

 

What are you using for nutrient export?  I've found my fuge with cheato seems to use Nitrates and Phosphates really quickly to the point that I've had to dose KNO3 with my ATO water to avoid corals bleaching out.  I don't run a skimmer.

[empresto]

I've also been running carbon and replacing that every month or so.  My theory is that it should removes some of the contaminants that would otherwise build up in the system without water changes.

[FISHnChix]

Yep I started doing the same thing and corals seem to be doing better.. but I am also using brs 2 part.. for now I am just dosing by hand every couple days and seems to be working.  I am setting up a doser this weekend to hopefully make it more stable.. i have been running cheato in my intank basket for months now and haven't had a nitrate reading since (So low I might start dosing for nitrates) I am only 3 weeks into my limited w.c. experiment and so far nitrates are still zero so I will see what happens..

[NanoRox]

I am currently running carbon and filter floss changed out every three days or so.  Also running a chaeto reactor for export.  I am also dosing 1.5 ml of nitrate per week in the ato because my nitrates disappeared once I started up the reactor.  Nitrates are running around 1 ppm.   I harvest the chaeto every two weeks.  I am waiting for API water tests to come back in about a week.  I chose API because they read nitrates in addition to everything else.  I will post results when I get them back. 

[FISHnChix]

19 minutes ago, Duane Clark said:

I am currently running carbon and filter floss changed out every three days or so.  Also running a chaeto reactor for export.  I am also dosing 1.5 ml of nitrate per week in the ato because my nitrates disappeared once I started up the reactor.  Nitrates are running around 1 ppm.   I harvest the chaeto every two weeks.  I am waiting for API water tests to come back in about a week.  I chose API because they read nitrates in addition to everything else.  I will post results when I get them back. 

What are you using for nitrate???

[NanoRox]

https://premiumaquatics.com/products/coral-nitrate-32-oz.html

 

simple to use!  

[Subsea]

With large systems, cutting back on water change volumes makes sense with both pocket book and labor.   When I operated 10K gallon system in greenhouse, I evaporated 100 gal/day which is the equivalent of 850,000 BTU’s of cooling.

[NanoRox]

3 minutes ago, Subsea said:

With large systems, cutting back on water change volumes makes sense with both pocket book and labor.   When I operated 10K gallon system in greenhouse, I evaporated 100 gal/day which is the equivalent of 850,000 BTU’s of cooling.

Omg...that’s insane 

[FISHnChix]

44 minutes ago, Subsea said:

With large systems, cutting back on water change volumes makes sense with both pocket book and labor.   When I operated 10K gallon system in greenhouse, I evaporated 100 gal/day which is the equivalent of 850,000 BTU’s of cooling.

Whoa.. makws me wonder how much water a day I evap from my pool at 26k gallon and summer temps that stay over 100 degrees ..

 

 

[Clown79]

I was in a situation a few mnths ago where I missed a weekly waterchange on my 10g.

 

And then another one was missed.

 

The tank never looked better so I am now doing a waterchange every 2 weeks on the 10g. 

I still need to dose daily esv bionic to prevent fluctuations.

[markalot]

I have not done a significant water change to either of my tanks for over a year.    Well, in my 40 it started to stink, probably the leather coral, so I changed 10% and added carbon, but that's it.   

 

My corals do fine, including Acros in my large tank, but I'm not positive it's healthy for the fish.  In Freshwater you can measure TDS and try and keep it in a decent range, for a reef that doesn't work.  ICP testing should be a decent answer, but there's a lot of toxins that won't be on the test.   

 

And, the disclaimer for the no water change threads ... try this in a newer tank and you are doomed.  :)

[NanoRox]

44 minutes ago, Weikel said:

Whoa.. makws me wonder how much water a day I evap from my pool at 26k gallon and summer temps that stay over 100 degrees ..

 

 

Same here.  Completely insane thought but wouldn’t it be cool to convert a saltwater pool to a huge back yard reef? Remove the salt cell and apply some of the same husbandry principles in large scale and why not?  

[NanoRox]

3 minutes ago, markalot said:

I have not done a significant water change to either of my tanks for over a year.    Well, in my 40 it started to stink, probably the leather coral, so I changed 10% and added carbon, but that's it.   

 

My corals do fine, including Acros in my large tank, but I'm not positive it's healthy for the fish.  In Freshwater you can measure TDS and try and keep it in a decent range, for a reef that doesn't work.  IPS testing should be a decent answer, but there's a lot of toxins that won't be on the test.   

 

And, the disclaimer for the no water change threads ... try this in a newer tank and you are doomed.  🙂

Doomed is right.  My tank is just now 7 months old so technically a new tank so not recommended.    As to the fish they are very healthy so far.  Then again I have a very light Bioload.  I hope to upgrade to a much larger system one day and would love to see if I can get to at least a 6 month range. 

[Subsea]

16 minutes ago, markalot said:

I have not done a significant water change to either of my tanks for over a year.    Well, in my 40 it started to stink, probably the leather coral, so I changed 10% and added carbon, but that's it.   

 

My corals do fine, including Acros in my large tank, but I'm not positive it's healthy for the fish.  In Freshwater you can measure TDS and try and keep it in a decent range, for a reef that doesn't work.  ICP testing should be a decent answer, but there's a lot of toxins that won't be on the test.   

 

And, the disclaimer for the no water change threads ... try this in a newer tank and you are doomed.  🙂

There is some very complex biochemistry and coral bacteria symbiotic interactions that help explain why this happens.

 

https://www.advancedaquarist.com/2017/9/aafeature

 

In this Advanced Aquaria article “The Carbon Continuum”, Kenneth Wingertef starts out where Ken Feldman and Dana Riddle left off.  Research shows that coral selectively harvest specific bacteria and cultivate the growth of that bacteria with growth harmones.  

So, when we change out water, we alter the chemistry of coral cultivating bacteria.   Sounds like a Master Gardner cultivating his garden.   In further reading the article, the fact that 60% of the food energy of the reef is tied up in this microbial loop.  This is how corals feed themselves.  Combine the “microbial loop” with the “carbon pump”. and your tank will feed itself.

[NanoRox]

2 minutes ago, Subsea said:

There is some very complex biochemistry and coral bacteria symbiotic interactions that help explain why this happens.

 

https://www.advancedaquarist.com/2017/9/aafeature

 

In this Advanced Aquaria article “The Carbon Continuum”, Kenneth Wingertef starts out where Ken Feldman and Dana Riddle left off.  Research shows that coral selectively harvest specific bacteria and cultivate the growth of that bacteria with growth harmones.  

So, when we change out water, we alter the chemistry of coral cultivating bacteria.   Sounds like a Master Gardner cultivating his garden.   In further reading the article, the fact that 60% of the food energy of the reef is tied up in this microbial loop.  This is how corals feed themselves.  Combine the “microbial loop” with the “carbon pump”. and your tank will feed itself.

Seems we are seeing that play out even in our own little microsomes.  This is why our hobby is so fascinating.  

[Subsea]

1 hour ago, Weikel said:

Whoa.. makws me wonder how much water a day I evap from my pool at 26k gallon and summer temps that stay over 100 degrees ..

 

 

Depends on how cool you want your water to be.  Because I intended to grow  coral in the Big Tank, I wanted temperature of the water < 82 degrees.  To push the system, I maintained 10K gal of water below 80 degrees when outside temperatures was 105 degrees.  Dew point allows evaporative cooling to lower water temperature 20 degrees below hot dry air.

[NanoRox]

UPDATE:  Just received my ATI water test results.  I scored an 85 overall quality.  Items that should be corrected:

 

1. Nitrate is .01.  Even with dosing I need to increase that.  The chaeto is so efficient at exporting it.

2. Zinc is too high.  My RODI was also tested and was all 0's so I am not sure where the source is.  the reference value was 1.84ug/l.  my result was 10.07 ug/l.  Could it be from my food?

3, I need to supplement potassium, bromine and iodine.  

 

All of these things are manageable so I am pretty happy with the results. 

 

Would love some idea on possible zinc sources if you guys have any ideas. 

 

EDIT- I may have just answered my own question regarding the zinc.  Copper is zero so I am confident I don’t have any exposed electrical components BUT aluminum is slightly elevated but still within normal ranges so I am thinking my aluminum frame to my tank cover is the culprit because it does get wet.  Not sure how I am supposed to stop that. 

 

Also, while I am thinking about it, I am not sure how bad 10 ug/l is.  I read a study just recently that found levels did not negatively impact corals and their symbiotic chlorophyll until 100ug/l.  Anyway, perhaps I can now justify getting one of those nifty custom acrylic lids.  🙂 

[seabass]

1 hour ago, Duane Clark said:

Would love some idea on possible zinc sources if you guys have any ideas. 

Do you have any metal in or above the tank which could be corroding?

 

Edit: Just saw your edit. 

[NanoReeferNY]

I know a few people who have great results with this, theory is your replenishing very little elements back into tank with a water change, and if you have a good skimmer, plus dosing habits you can pretty much get away with it these days - 

 

I've yet to do one myself since my system went up 5 mos ago and my tank is looking better than ever these days! 

[NanoRox]

19 minutes ago, seabass said:

Do you have any metal in or above the tank which could be corroding?

 

Edit: Just saw your edit. 

Ha yeah...I thought of that shortly after posting.  May not be anything worth chasing BUT like I said, now I can justify getting a fancy acrylic cover. 😉 

[NanoRox]

6 minutes ago, NanoReeferNY said:

I know a few people who have great results with this, theory is your replenishing very little elements back into tank with a water change, and if you have a good skimmer, plus dosing habits you can pretty much get away with it these days - 

 

I've yet to do one myself since my system went up 5 mos ago and my tank is looking better than ever these days! 

Wait, am I reading that correctly?  You have set up a tank and no water changes yet? If that is the case I need to sit down with you and learn everything you know.  That’s impressive.  

[seabass]

19 hours ago, Duane Clark said:

I have been cutting back on my water changes for the past maybe two months to mitigate some of the water parameter fluctuations I was seeing with every change

I've been advocating that we should be dosing our tanks to target levels equivalent to a freshly mixed batch of saltwater.  That way, water changes do not cause wild parameter fluctuations.

 

13 hours ago, Subsea said:

There is some very complex biochemistry and coral bacteria symbiotic interactions that help explain why this happens.

https://www.advancedaquarist.com/2017/9/aafeature

Articles like that make me question just how much I really know about reefing, but a good article nonetheless.

 

@Subsea, how long do you think that it takes, for a tank to mature, before we see these interactions in our tanks?  I feel that many of us get too obsessed with killing algae with peroxide, using dry rock to prevent pests, and maintaining the sterile environment of a new reef tank, that we never see the benefits described in the article.  I've been making more of an effort to let my tanks mature, to increase biodiversity, and enhance the natural food chains.

 

 

 

[NanoRox]

7 minutes ago, seabass said:

I've been advocating that we should be dosing our tanks to target levels equivalent to a freshly mixed batch of saltwater.  That way, water changes do not cause wild parameter fluctuations.

This makes complete sense but I found it very difficult for me to match the numbers coming from my salt (Fritz Pro).   The fluctuations I kept seeing were a result of my trying I think.  For me, it seemed more feasible to start there as a base and then achieve my desired numbers and then maintain as long as I can based on my corals nutrient uptake.

 

And to think when I started i thought the chemistry of tank water would be intimidating.  Turns out this is really fun stuff.  

[Clown79]

50 minutes ago, Duane Clark said:

This makes complete sense but I found it very difficult for me to match the numbers coming from my salt (Fritz Pro).   The fluctuations I kept seeing were a result of my trying I think.  For me, it seemed more feasible to start there as a base and then achieve my desired numbers and then maintain as long as I can based on my corals nutrient uptake.

 

And to think when I started i thought the chemistry of tank water would be intimidating.  Turns out this is really fun stuff.  

The one important factor is, when not doing waterchanges, it's very important to dose alk and ca as the more lps and sps you have, the more they will drop.

 

Test your tank after a waterchange for alk and ca. That would be your target numbers.

 

Test tank every day

 

Dose according to the drop from your target number.

 

So if your alk is 7.8 after waterchange, that's what you want to maintain daily.

 

Be careful with online calculators for dosing.

 

To date they have given me inaccurate quantities to dose.

 

 

 

If you are trying to keep alk at per say 9 but your salt isn't mixing at 9 and your tank after a waterchange isn't 9- trying to get it to 9 and maintain it is much more work and comes with fluctuations.

You'd need to dose your mixed water before the water change then dose to maintain.